From eeba62c2f1bddf8187ef5275a57d019283896465 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Mon, 6 Jul 2026 17:22:31 +0200
Subject: [PATCH 01/13] chore: trigger CI pipeline check


From 10d4f98c1f8d7c9dfdb72d1d81525d98ee2d66d2 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Thu, 9 Jul 2026 17:12:17 +0200
Subject: [PATCH 02/13] Add streamlined contribution workflows

---
 .github/CODEOWNERS                         |   3 +
 .github/ISSUE_TEMPLATE/bug_report.yml      |  34 +++++++
 .github/ISSUE_TEMPLATE/config.yml          |   8 ++
 .github/ISSUE_TEMPLATE/feature_request.yml |  20 ++++
 .github/PULL_REQUEST_TEMPLATE.md           |  36 +++++++
 .github/labeler.yml                        |  54 +++++++++++
 .github/workflows/assign-codeowners.yml    | 101 ++++++++++++++++++++
 .github/workflows/clang-format.yml         |  27 ++++++
 .github/workflows/codex-pr-review.yml      |  67 +++++++++++++
 .github/workflows/labeler.yml              |  47 +++++++++
 .github/workflows/mark-integrate.yml       |  76 +++++++++++++++
 .github/workflows/mtr-smoke.yml            |  89 +++++++++++++++++
 .github/workflows/pr-build.yml             |  99 +++++++++++++++++++
 .github/workflows/pr-template-check.yml    |  59 ++++++++++++
 .github/workflows/stale.yml                |  20 ++++
 CONTRIBUTING.md                            | 106 +++++++++++++++++++++
 Docs/development/BUILD-FROM-SOURCE.md      |  48 ++++++++++
 Docs/development/open-development-model.md |  83 ++++++++++++++++
 Docs/rfcs/0000-template.md                 |  32 +++++++
 Docs/rfcs/README.md                        |  18 ++++
 mysql-test/collections/smoke.list          |  10 ++
 scripts/dev/bootstrap.sh                   |  15 +++
 scripts/dev/build.sh                       |  29 ++++++
 scripts/dev/demo-labeler.sh                |  63 ++++++++++++
 scripts/dev/format.sh                      |  14 +++
 scripts/dev/mtr.sh                         |  24 +++++
 26 files changed, 1182 insertions(+)
 create mode 100644 .github/CODEOWNERS
 create mode 100644 .github/ISSUE_TEMPLATE/bug_report.yml
 create mode 100644 .github/ISSUE_TEMPLATE/config.yml
 create mode 100644 .github/ISSUE_TEMPLATE/feature_request.yml
 create mode 100644 .github/PULL_REQUEST_TEMPLATE.md
 create mode 100644 .github/labeler.yml
 create mode 100644 .github/workflows/assign-codeowners.yml
 create mode 100644 .github/workflows/clang-format.yml
 create mode 100644 .github/workflows/codex-pr-review.yml
 create mode 100644 .github/workflows/labeler.yml
 create mode 100644 .github/workflows/mark-integrate.yml
 create mode 100644 .github/workflows/mtr-smoke.yml
 create mode 100644 .github/workflows/pr-build.yml
 create mode 100644 .github/workflows/pr-template-check.yml
 create mode 100644 .github/workflows/stale.yml
 create mode 100644 CONTRIBUTING.md
 create mode 100644 Docs/development/BUILD-FROM-SOURCE.md
 create mode 100644 Docs/development/open-development-model.md
 create mode 100644 Docs/rfcs/0000-template.md
 create mode 100644 Docs/rfcs/README.md
 create mode 100644 mysql-test/collections/smoke.list
 create mode 100755 scripts/dev/bootstrap.sh
 create mode 100755 scripts/dev/build.sh
 create mode 100755 scripts/dev/demo-labeler.sh
 create mode 100755 scripts/dev/format.sh
 create mode 100755 scripts/dev/mtr.sh

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 0000000000..cd1db4ba36
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1,3 @@
+# Temporary default owners for every path. Replace this wildcard with
+# path-specific teams as the external committer model rolls out.
+* @seemasundara @gopshank
diff --git a/.github/ISSUE_TEMPLATE/bug_report.yml b/.github/ISSUE_TEMPLATE/bug_report.yml
new file mode 100644
index 0000000000..44f3858789
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -0,0 +1,34 @@
+name: Bug report
+description: Report incorrect or unexpected server behavior
+labels: ["bug", "needs-triage"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Security vulnerabilities must **not** be filed here. Report them through
+        <https://www.oracle.com/corporate/security-practices/assurance/vulnerability/>.
+  - type: input
+    id: version
+    attributes:
+      label: MySQL version / commit
+      placeholder: "9.x trunk @ <sha>, or 8.4.x"
+    validations: { required: true }
+  - type: textarea
+    id: repro
+    attributes:
+      label: Steps to reproduce
+      description: Minimal SQL or MTR case if possible.
+      placeholder: |
+        CREATE TABLE t (...);
+        ...
+    validations: { required: true }
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected vs actual result
+    validations: { required: true }
+  - type: input
+    id: platform
+    attributes:
+      label: Platform / compiler
+      placeholder: "Ubuntu 24.04, gcc 13"
diff --git a/.github/ISSUE_TEMPLATE/config.yml b/.github/ISSUE_TEMPLATE/config.yml
new file mode 100644
index 0000000000..76609cfcf8
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/config.yml
@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Security vulnerability
+    url: https://www.oracle.com/corporate/security-practices/assurance/vulnerability/
+    about: Report security issues privately through Oracle's process — never as a public issue.
+  - name: Usage questions / general help
+    url: https://forums.mysql.com/
+    about: For "how do I…" questions, please use the community forums.
diff --git a/.github/ISSUE_TEMPLATE/feature_request.yml b/.github/ISSUE_TEMPLATE/feature_request.yml
new file mode 100644
index 0000000000..7fc4a1105f
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/feature_request.yml
@@ -0,0 +1,20 @@
+name: Feature request
+description: Propose an enhancement
+labels: ["feature-request", "needs-triage"]
+body:
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem / use case
+    validations: { required: true }
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposed behavior
+    validations: { required: true }
+  - type: checkboxes
+    id: scope
+    attributes:
+      label: Scope
+      options:
+        - label: This changes SQL syntax, on-disk format, or public behavior (an RFC will be needed)
diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
new file mode 100644
index 0000000000..06a418cea3
--- /dev/null
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -0,0 +1,36 @@
+<!-- Thanks for contributing to MySQL Server! The prompts below are the few
+     things reviewers always need. Delete any that don't apply. -->
+
+### What does this change do?
+
+<!-- One or two sentences. Link the issue/bug it fixes: "Fixes #1234" or
+     "BUG#XXXXXXXX". -->
+
+### Why is it needed?
+
+### How was it tested?
+
+- [ ] Added/updated MTR tests under `mysql-test/`
+- [ ] `scripts/dev/mtr.sh smoke` passes locally
+- [ ] Ran the relevant full suite (name it): ______
+
+### Contributor checklist
+
+- [ ] I have signed the [OCA](https://oca.opensource.oracle.com) with the email on these commits
+- [ ] Code is formatted (`scripts/dev/format.sh`)
+- [ ] Commits are focused with descriptive messages
+- [ ] For a behavior/format/syntax change, an RFC was opened or linked: ______
+
+### AI assistance
+
+- [ ] I did not use AI assistance for this contribution
+- [ ] I used AI assistance for this contribution
+
+If AI assistance was used, describe the tool(s) and extent of use:
+
+<!-- e.g. brainstorming, code generation, test generation, refactoring, review.
+     Also mention which parts were human-reviewed or manually verified. -->
+
+### Areas touched
+
+<!-- e.g. innodb, optimizer, replication, client, build. Helps auto-routing. -->
diff --git a/.github/labeler.yml b/.github/labeler.yml
new file mode 100644
index 0000000000..1fd4c198b3
--- /dev/null
+++ b/.github/labeler.yml
@@ -0,0 +1,54 @@
+# Area auto-labels, driven by the paths a PR touches. Keeps triage cheap and
+# routes reviews to the right owners (see CODEOWNERS).
+#
+# Format note: actions/labeler@v5 requires the `changed-files` /
+# `any-glob-to-any-file` structure below. The older flat "label: [globs]"
+# layout (v4) is NOT compatible with v5 and fails to parse.
+
+"innodb":
+  - changed-files:
+      - any-glob-to-any-file: ["storage/innobase/**"]
+
+"optimizer":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "sql/join_optimizer/**"
+          - "sql/sql_optimizer*"
+          - "sql/range_optimizer/**"
+
+"replication":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "sql/rpl_*"
+          - "libbinlogevents/**"
+          - "plugin/group_replication/**"
+
+"client":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "client/**"
+          - "libmysql/**"
+
+"pluggable":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "plugin/**"
+          - "components/**"
+
+"build":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "cmake/**"
+          - "CMakeLists.txt"
+          - "scripts/dev/**"
+          - ".github/**"
+
+"tests":
+  - changed-files:
+      - any-glob-to-any-file: ["mysql-test/**"]
+
+"docs":
+  - changed-files:
+      - any-glob-to-any-file:
+          - "docs/**"
+          - "**/*.md"
diff --git a/.github/workflows/assign-codeowners.yml b/.github/workflows/assign-codeowners.yml
new file mode 100644
index 0000000000..bd0bea98fc
--- /dev/null
+++ b/.github/workflows/assign-codeowners.yml
@@ -0,0 +1,101 @@
+name: Assign Code Owners
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review, labeled]
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+concurrency:
+  group: assign-codeowners-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  assign:
+    if: ${{ !github.event.pull_request.draft && contains(github.event.pull_request.labels.*.name, 'OCA Verified') }}
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Request review from code owners
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const pr = context.payload.pull_request;
+            // TODO: Before upstream merge, change this test ref to 'trunk'.
+            const codeownersRef = 'codex/ci-cd-pipeline-test';
+            const path = '.github/CODEOWNERS';
+
+            const response = await github.rest.repos.getContent({
+              ...context.repo,
+              path,
+              ref: codeownersRef,
+            });
+            if (Array.isArray(response.data) || response.data.type !== 'file' || !response.data.content) {
+              throw new Error(`${path} at ${codeownersRef} is not a readable file`);
+            }
+
+            const codeowners = Buffer.from(response.data.content, 'base64').toString('utf8');
+            const defaultLine = codeowners
+              .split(/\r?\n/)
+              .map((line) => line.replace(/\s+#.*$/, '').trim())
+              .find((line) => line && !line.startsWith('#') && line.split(/\s+/)[0] === '*');
+            if (!defaultLine) {
+              throw new Error(`No wildcard owner rule found in ${path} at ${codeownersRef}`);
+            }
+
+            const owners = [...new Set(
+              defaultLine
+                .split(/\s+/)
+                .slice(1)
+                .filter((owner) => owner.startsWith('@'))
+                .map((owner) => owner.slice(1))
+                .filter(Boolean),
+            )];
+            if (owners.length === 0) {
+              throw new Error(`Wildcard rule in ${path} has no GitHub user owners`);
+            }
+
+            const current = await github.rest.pulls.get({
+              ...context.repo,
+              pull_number: pr.number,
+            });
+            const author = pr.user.login.toLowerCase();
+            const existing = new Set(
+              current.data.requested_reviewers.map((reviewer) => reviewer.login.toLowerCase()),
+            );
+            const eligible = owners.filter((owner) => owner.toLowerCase() !== author);
+            if (eligible.length === 0) {
+              throw new Error('No eligible code owners remain after excluding the pull request author');
+            }
+
+            const reviewers = eligible.filter((owner) => !existing.has(owner.toLowerCase()));
+            if (reviewers.length > 0) {
+              await github.rest.pulls.requestReviewers({
+                ...context.repo,
+                pull_number: pr.number,
+                reviewers,
+              });
+            }
+
+            const label = {
+              name: 'Review Requested',
+              color: '1D76DB',
+              description: 'Review requested from code owners',
+            };
+            try {
+              await github.rest.issues.getLabel({ ...context.repo, name: label.name });
+              await github.rest.issues.updateLabel({ ...context.repo, ...label });
+            } catch (error) {
+              if (error.status !== 404) throw error;
+              await github.rest.issues.createLabel({ ...context.repo, ...label });
+            }
+            await github.rest.issues.addLabels({
+              ...context.repo,
+              issue_number: pr.number,
+              labels: [label.name],
+            });
+
+            const assigned = reviewers.length > 0 ? reviewers : eligible;
+            core.info(`Review requested from ${assigned.map((owner) => `@${owner}`).join(', ')}.`);
diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
new file mode 100644
index 0000000000..fb1b546eb8
--- /dev/null
+++ b/.github/workflows/clang-format.yml
@@ -0,0 +1,27 @@
+name: Format Check
+on:
+  pull_request:
+    paths: ["**/*.c", "**/*.cc", "**/*.cpp", "**/*.h", "**/*.hpp"]
+jobs:
+  clang-format:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: refs/pull/${{ github.event.pull_request.number }}/merge
+          fetch-depth: 2
+      - name: Install clang-format
+        run: sudo apt-get update && sudo apt-get install -y clang-format-18
+      # Uses the repository's existing .clang-format — no style is redefined here.
+      - name: Check formatting of changed files
+        run: |
+          changed=$(git diff --name-only HEAD^1 HEAD | grep -E '\.(c|cc|cpp|h|hpp)$' || true)
+          [ -z "$changed" ] && { echo "No C/C++ changes."; exit 0; }
+          fail=0
+          for f in $changed; do
+            [ -f "$f" ] || continue
+            if ! clang-format-18 --style=file --dry-run --Werror "$f"; then fail=1; fi
+          done
+          if [ "$fail" -ne 0 ]; then
+            echo "::error::Run scripts/dev/format.sh to fix formatting."; exit 1
+          fi
diff --git a/.github/workflows/codex-pr-review.yml b/.github/workflows/codex-pr-review.yml
new file mode 100644
index 0000000000..c75fab9e8b
--- /dev/null
+++ b/.github/workflows/codex-pr-review.yml
@@ -0,0 +1,67 @@
+name: Codex PR Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+
+permissions:
+  contents: read
+
+jobs:
+  codex:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-24.04
+    timeout-minutes: 20
+    outputs:
+      final_message: ${{ steps.run_codex.outputs.final-message }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: refs/pull/${{ github.event.pull_request.number }}/merge
+          fetch-depth: 2
+          persist-credentials: false
+
+      - name: Summarize and review with Codex
+        id: run_codex
+        uses: openai/codex-action@v1
+        with:
+          openai-api-key: ${{ secrets.OPENAI_API_KEY }}
+          sandbox: read-only
+          prompt: |
+            This is PR #${{ github.event.pull_request.number }} for ${{ github.repository }}.
+
+            Summarize the changes and review only the diff introduced by this PR:
+              git diff --stat HEAD^1 HEAD
+              git diff HEAD^1 HEAD
+
+            Return:
+            1. A concise change summary.
+            2. High-confidence review findings, with file paths and line references when possible.
+            3. Any test gaps or risks.
+
+            Pull request title and body:
+            ----
+            ${{ github.event.pull_request.title }}
+            ${{ github.event.pull_request.body }}
+
+  post_feedback:
+    runs-on: ubuntu-24.04
+    needs: codex
+    if: needs.codex.outputs.final_message != ''
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - name: Post Codex feedback
+        uses: actions/github-script@v7
+        env:
+          CODEX_FINAL_MESSAGE: ${{ needs.codex.outputs.final_message }}
+        with:
+          github-token: ${{ github.token }}
+          script: |
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.payload.pull_request.number,
+              body: process.env.CODEX_FINAL_MESSAGE,
+            });
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
new file mode 100644
index 0000000000..f223b63d42
--- /dev/null
+++ b/.github/workflows/labeler.yml
@@ -0,0 +1,47 @@
+name: Auto Label
+
+# TODO: CHANGE BEFORE MERGE -> revert the trigger below to `pull_request_target`.
+#
+# `pull_request_target` is what the real upstream needs: it runs in the context
+# of the BASE repo and hands the job a write-scoped token even for PRs opened
+# from forks, so external contributors' PRs can still be labeled. It is set to
+# `pull_request` here only for this fork PoC because:
+#   1) a `pull_request_target` workflow must already exist on the base branch
+#      (trunk) to run at all, which it does not on this very first PR; and
+#   2) this PR is same-repo (head and base both on RidhaOracle/mysql-server),
+#      so `pull_request` already carries a write token and can apply labels.
+on: [pull_request]        # TODO: CHANGE BEFORE MERGE -> [pull_request_target]
+
+permissions: { contents: read, pull-requests: write, issues: write }
+
+jobs:
+  label:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Ensure labels have colors
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const labels = [
+              { name: 'innodb', color: '1D76DB', description: 'Changes touching InnoDB storage engine code' },
+              { name: 'optimizer', color: '5319E7', description: 'Changes touching optimizer code' },
+              { name: 'replication', color: '0052CC', description: 'Changes touching replication or binlog code' },
+              { name: 'client', color: '0E8A16', description: 'Changes touching client or libmysql code' },
+              { name: 'pluggable', color: 'FBCA04', description: 'Changes touching plugins or components' },
+              { name: 'build', color: 'D93F0B', description: 'Changes touching build or GitHub automation' },
+              { name: 'tests', color: 'BFDADC', description: 'Changes touching test code or test data' },
+              { name: 'docs', color: '0075CA', description: 'Changes touching documentation' },
+            ];
+
+            for (const label of labels) {
+              try {
+                await github.rest.issues.getLabel({ ...context.repo, name: label.name });
+                await github.rest.issues.updateLabel({ ...context.repo, ...label });
+              } catch (error) {
+                if (error.status !== 404) throw error;
+                await github.rest.issues.createLabel({ ...context.repo, ...label });
+              }
+            }
+
+      - uses: actions/labeler@v5
+        with: { sync-labels: true }
diff --git a/.github/workflows/mark-integrate.yml b/.github/workflows/mark-integrate.yml
new file mode 100644
index 0000000000..92edb5b2ae
--- /dev/null
+++ b/.github/workflows/mark-integrate.yml
@@ -0,0 +1,76 @@
+name: Mark Integrate
+
+on:
+  pull_request_review:
+    types: [submitted, dismissed]
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+concurrency:
+  group: mark-integrate-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  integrate:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Reconcile integrate label
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const pr = context.payload.pull_request;
+            const label = {
+              name: 'integrate',
+              color: '5319E7',
+              description: 'Approved patch ready for integration',
+            };
+
+            try {
+              await github.rest.issues.getLabel({ ...context.repo, name: label.name });
+              await github.rest.issues.updateLabel({ ...context.repo, ...label });
+            } catch (error) {
+              if (error.status !== 404) throw error;
+              await github.rest.issues.createLabel({ ...context.repo, ...label });
+            }
+
+            const reviews = await github.paginate(github.rest.pulls.listReviews, {
+              ...context.repo,
+              pull_number: pr.number,
+              per_page: 100,
+            });
+            const meaningfulStates = new Set(['APPROVED', 'CHANGES_REQUESTED', 'DISMISSED']);
+            const latestStates = new Map();
+
+            for (const review of reviews) {
+              const login = review.user?.login;
+              if (login && meaningfulStates.has(review.state)) {
+                latestStates.set(login, review.state);
+              }
+            }
+
+            const approvers = [...latestStates.entries()]
+              .filter(([, state]) => state === 'APPROVED')
+              .map(([login]) => login);
+
+            if (approvers.length > 0) {
+              await github.rest.issues.addLabels({
+                ...context.repo,
+                issue_number: pr.number,
+                labels: [label.name],
+              });
+              core.info(`Marked PR #${pr.number} as integrate; active approvals: ${approvers.join(', ')}.`);
+            } else {
+              try {
+                await github.rest.issues.removeLabel({
+                  ...context.repo,
+                  issue_number: pr.number,
+                  name: label.name,
+                });
+              } catch (error) {
+                if (error.status !== 404) throw error;
+              }
+              core.info(`Removed integrate from PR #${pr.number}; no active approvals remain.`);
+            }
diff --git a/.github/workflows/mtr-smoke.yml b/.github/workflows/mtr-smoke.yml
new file mode 100644
index 0000000000..e797b0f54b
--- /dev/null
+++ b/.github/workflows/mtr-smoke.yml
@@ -0,0 +1,89 @@
+name: MTR Smoke
+on:
+  pull_request:
+    # TODO: Before upstream merge, change this test target back to 'trunk'.
+    branches: [5.7]
+    paths-ignore: ["docs/**", "**/*.md"]
+
+permissions:
+  contents: read
+  issues: write
+
+concurrency:
+  group: mtr-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+# Fast, curated test signal on every PR. The full suite (innodb, replication,
+# rpl, group_replication, …) runs nightly on trunk, not per-PR, to keep the
+# contributor feedback loop under ~20 minutes.
+jobs:
+  smoke:
+    runs-on: ubuntu-24.04-8core
+    needs: []
+    timeout-minutes: 45
+    steps:
+      - uses: actions/checkout@v4
+      - run: scripts/dev/bootstrap.sh
+      - uses: actions/cache@v4
+        with:
+          path: ~/.cache/mysql-boost
+          key: boost-${{ hashFiles('cmake/boost.cmake') }}
+      - uses: actions/cache@v4
+        with:
+          path: ~/.cache/ccache
+          key: ccache-gcc-${{ github.sha }}
+          restore-keys: ccache-gcc-
+      - run: scripts/dev/build.sh debug
+      - name: Run smoke suite
+        run: scripts/dev/mtr.sh smoke
+      - name: Publish test report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: mtr-smoke-logs
+          path: build/mysql-test/var/log/
+          retention-days: 5
+
+  report:
+    name: Label MTR result
+    if: ${{ always() && !cancelled() }}
+    needs: smoke
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Update MTR result label
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const passed = '${{ needs.smoke.result }}' === 'success';
+            const labels = [
+              { name: 'MTR Passed', color: '0E8A16', description: 'MTR smoke suite passed' },
+              { name: 'MTR Failed', color: 'D93F0B', description: 'MTR smoke suite failed' },
+            ];
+
+            for (const label of labels) {
+              try {
+                await github.rest.issues.getLabel({ ...context.repo, name: label.name });
+                await github.rest.issues.updateLabel({ ...context.repo, ...label });
+              } catch (error) {
+                if (error.status !== 404) throw error;
+                await github.rest.issues.createLabel({ ...context.repo, ...label });
+              }
+            }
+
+            const selected = passed ? labels[0] : labels[1];
+            const opposite = passed ? labels[1] : labels[0];
+            try {
+              await github.rest.issues.removeLabel({
+                ...context.repo,
+                issue_number: context.payload.pull_request.number,
+                name: opposite.name,
+              });
+            } catch (error) {
+              if (error.status !== 404) throw error;
+            }
+            await github.rest.issues.addLabels({
+              ...context.repo,
+              issue_number: context.payload.pull_request.number,
+              labels: [selected.name],
+            });
+            core.info(`Set PR #${context.payload.pull_request.number} to ${selected.name}.`);
diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
new file mode 100644
index 0000000000..9504d7457b
--- /dev/null
+++ b/.github/workflows/pr-build.yml
@@ -0,0 +1,99 @@
+name: PR Build
+on:
+  pull_request:
+    # TODO: Before upstream merge, change this test target back to 'trunk'.
+    branches: [5.7]
+    paths-ignore: ["docs/**", "**/*.md"]
+
+permissions:
+  contents: read
+  issues: write
+
+# Cancel superseded runs so a fast push doesn't queue behind a stale build.
+concurrency:
+  group: build-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    name: Debug build (${{ matrix.compiler }})
+    runs-on: ubuntu-24.04-8core
+    timeout-minutes: 90
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [gcc, clang]
+    env:
+      CC: ${{ matrix.compiler == 'gcc' && 'gcc' || 'clang' }}
+      CXX: ${{ matrix.compiler == 'gcc' && 'g++' || 'clang++' }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install toolchain
+        run: scripts/dev/bootstrap.sh
+      # Boost is large and version-pinned: cache it so most runs skip the download.
+      - name: Cache Boost
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/mysql-boost
+          key: boost-${{ hashFiles('cmake/boost.cmake') }}
+      # ccache turns the second build of a PR from ~50 min into a few minutes.
+      - name: Cache ccache
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/ccache
+          key: ccache-${{ matrix.compiler }}-${{ github.sha }}
+          restore-keys: ccache-${{ matrix.compiler }}-
+      - name: Show runner resources
+        run: |
+          echo "CPU cores: $(nproc)"
+          free -h
+          df -h .
+      - name: Build
+        run: scripts/dev/build.sh debug
+      - name: Show ccache stats
+        if: always()
+        run: ccache --show-stats
+
+  report:
+    name: Label build result
+    if: ${{ always() && !cancelled() }}
+    needs: build
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Update build result label
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const passed = '${{ needs.build.result }}' === 'success';
+            const labels = [
+              { name: 'Build Passed', color: '0E8A16', description: 'PR build passed' },
+              { name: 'Build Failed', color: 'D93F0B', description: 'PR build failed' },
+            ];
+
+            for (const label of labels) {
+              try {
+                await github.rest.issues.getLabel({ ...context.repo, name: label.name });
+                await github.rest.issues.updateLabel({ ...context.repo, ...label });
+              } catch (error) {
+                if (error.status !== 404) throw error;
+                await github.rest.issues.createLabel({ ...context.repo, ...label });
+              }
+            }
+
+            const selected = passed ? labels[0] : labels[1];
+            const opposite = passed ? labels[1] : labels[0];
+            try {
+              await github.rest.issues.removeLabel({
+                ...context.repo,
+                issue_number: context.payload.pull_request.number,
+                name: opposite.name,
+              });
+            } catch (error) {
+              if (error.status !== 404) throw error;
+            }
+            await github.rest.issues.addLabels({
+              ...context.repo,
+              issue_number: context.payload.pull_request.number,
+              labels: [selected.name],
+            });
+            core.info(`Set PR #${context.payload.pull_request.number} to ${selected.name}.`);
diff --git a/.github/workflows/pr-template-check.yml b/.github/workflows/pr-template-check.yml
new file mode 100644
index 0000000000..6a64c9a9ee
--- /dev/null
+++ b/.github/workflows/pr-template-check.yml
@@ -0,0 +1,59 @@
+name: PR Template Check
+
+on:
+  pull_request:
+    paths:
+      - ".github/PULL_REQUEST_TEMPLATE.md"
+      - ".github/workflows/pr-template-check.yml"
+
+permissions:
+  contents: read
+
+jobs:
+  template:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Verify suggested pull request template
+        run: |
+          cat > expected-pr-template.md <<'EOF'
+          <!-- Thanks for contributing to MySQL Server! The prompts below are the few
+               things reviewers always need. Delete any that don't apply. -->
+
+          ### What does this change do?
+
+          <!-- One or two sentences. Link the issue/bug it fixes: "Fixes #1234" or
+               "BUG#XXXXXXXX". -->
+
+          ### Why is it needed?
+
+          ### How was it tested?
+
+          - [ ] Added/updated MTR tests under `mysql-test/`
+          - [ ] `scripts/dev/mtr.sh smoke` passes locally
+          - [ ] Ran the relevant full suite (name it): ______
+
+          ### Contributor checklist
+
+          - [ ] I have signed the [OCA](https://oca.opensource.oracle.com) with the email on these commits
+          - [ ] Code is formatted (`scripts/dev/format.sh`)
+          - [ ] Commits are focused with descriptive messages
+          - [ ] For a behavior/format/syntax change, an RFC was opened or linked: ______
+
+          ### AI assistance
+
+          - [ ] I did not use AI assistance for this contribution
+          - [ ] I used AI assistance for this contribution
+
+          If AI assistance was used, describe the tool(s) and extent of use:
+
+          <!-- e.g. brainstorming, code generation, test generation, refactoring, review.
+               Also mention which parts were human-reviewed or manually verified. -->
+
+          ### Areas touched
+
+          <!-- e.g. innodb, optimizer, replication, client, build. Helps auto-routing. -->
+          EOF
+          perl -pi -e 's/^          //' expected-pr-template.md
+          diff -u expected-pr-template.md .github/PULL_REQUEST_TEMPLATE.md
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
new file mode 100644
index 0000000000..81fa72cf6b
--- /dev/null
+++ b/.github/workflows/stale.yml
@@ -0,0 +1,20 @@
+name: Triage Hygiene
+on:
+  schedule: [{ cron: "0 6 * * 1-5" }]   # weekday mornings
+permissions: { issues: write, pull-requests: write }
+
+# Gentle: only nudges items explicitly waiting on the author for info. Nothing
+# labeled good-first-issue, help-wanted, or under active review is ever touched.
+jobs:
+  stale:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/stale@v9
+        with:
+          only-labels: "needs-info"
+          days-before-stale: 21
+          days-before-close: 14
+          stale-issue-message: "Marking as stale: still waiting on the requested info. Comment to keep it open."
+          stale-pr-message: "Marking as stale: waiting on requested changes. Push or comment to keep it open."
+          exempt-pr-labels: "good first issue,help wanted,under-review"
+          exempt-issue-labels: "good first issue,help wanted,roadmap"
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000000..4282cc40ae
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,106 @@
+# Contributing to MySQL Server
+
+We welcome your code contributions. This guide gets you from a fresh clone to a
+merged pull request with as little friction as possible.
+
+> **TL;DR** — Sign the [OCA](https://oca.opensource.oracle.com), run
+> `scripts/dev/bootstrap.sh`, make your change, run `scripts/dev/mtr.sh smoke`,
+> and open a PR. CI builds your branch and runs a smoke suite automatically. A
+> maintainer is assigned within the triage SLA below.
+
+---
+
+## 1. Sign the Oracle Contributor Agreement (once)
+
+Before any contribution can be merged you must have signed the
+[Oracle Contributor Agreement (OCA)](https://oca.opensource.oracle.com).
+
+1. Create or reuse a user account at <https://bugs.mysql.com>.
+2. Sign the OCA, referencing that account.
+3. Use the **same email** on your Git commits (`git config user.email`).
+
+Oracle verifies OCA status separately from this repository's GitHub Actions
+workflows. Follow any OCA guidance reported on the pull request before the
+change is merged.
+
+## 2. Get a build in one command
+
+Full instructions live in [`docs/development/BUILD-FROM-SOURCE.md`](docs/development/BUILD-FROM-SOURCE.md).
+The fast path:
+
+```bash
+# Reproducible toolchain + Boost, identical to CI:
+scripts/dev/bootstrap.sh        # installs/pins deps
+scripts/dev/build.sh debug      # configures + builds into build/
+```
+
+These scripts pin the same compiler, CMake, Ninja, Boost, and test tooling used
+by CI, so "works locally" tracks "passes in CI."
+
+## 3. Find something to work on
+
+- Issues labeled [`good first issue`](../../labels/good%20first%20issue) are
+  scoped, have reproduction steps, and a named area owner.
+- [`help wanted`](../../labels/help%20wanted) marks larger items the team would
+  welcome help on.
+- For a substantial change (new syntax, on-disk format, public behavior), open a
+  short **RFC** first — see [`docs/rfcs/`](docs/rfcs/). This avoids investing in a
+  branch that conflicts with internal direction, the single most common reason
+  external work has historically stalled.
+
+## 4. Make the change
+
+- Match existing style; formatting is enforced by `.clang-format`. Run
+  `scripts/dev/format.sh` (or install the pre-commit hook below) so you never get
+  a review comment about whitespace.
+- Add or update tests. Every behavior change ships with MTR coverage under
+  `mysql-test/`. See `docs/development/BUILD-FROM-SOURCE.md#running-tests`.
+- Keep commits focused and write a clear message body explaining *why*.
+
+Optional but recommended — install the format pre-commit hook:
+
+```bash
+ln -s ../../scripts/dev/format.sh .git/hooks/pre-commit
+```
+
+## 5. Run tests locally (the same ones CI runs)
+
+```bash
+scripts/dev/mtr.sh smoke      # ~5 min curated subset, mirrors the PR check
+scripts/dev/mtr.sh main       # full main suite
+scripts/dev/mtr.sh --suite=innodb     # pass MTR args straight through
+```
+
+## 6. Open the pull request
+
+Push your branch and open a PR against `trunk`. The
+[pull request template](.github/PULL_REQUEST_TEMPLATE.md) prompts for the few
+things reviewers always need. On open, CI automatically:
+
+- checks formatting,
+- builds Debug on gcc and clang,
+- runs the smoke MTR suite,
+- auto-labels the affected area and assigns a reviewer.
+
+You should see green (or actionable red) within ~20 minutes — without asking
+anyone.
+
+## What to expect from us (triage SLAs)
+
+These are the response targets the maintainers hold themselves to. They are
+published here so the contract is mutual and visible:
+
+| Stage                                   | Target            |
+|-----------------------------------------|-------------------|
+| First maintainer response on a new PR   | 3 business days   |
+| First response on a `good first issue`  | 2 business days   |
+| Review round-trip after you push        | 5 business days   |
+| Decision on an RFC                       | 15 business days  |
+
+If a PR goes quiet past these windows, ping `@mysql/triage` on the thread.
+
+## Alternative submission path
+
+You may still attach a patch to a bug record at <https://bugs.mysql.com> via the
+*contribution* tab. GitHub pull requests are now the recommended path because
+they get automated CI feedback and public review history.
diff --git a/Docs/development/BUILD-FROM-SOURCE.md b/Docs/development/BUILD-FROM-SOURCE.md
new file mode 100644
index 0000000000..03ca36a704
--- /dev/null
+++ b/Docs/development/BUILD-FROM-SOURCE.md
@@ -0,0 +1,48 @@
+# Building MySQL Server from source
+
+The canonical reference is <https://dev.mysql.com/doc/dev/mysql-server/latest/>.
+This page is the *fast path* for contributors and is kept in sync with what CI
+runs, so following it reproduces the automated checks locally.
+
+## Native Ubuntu 24.04
+
+```bash
+scripts/dev/bootstrap.sh        # toolchain + libs
+scripts/dev/build.sh debug      # configure (Ninja) + build into build/
+```
+
+`build.sh` invokes CMake with `-DDOWNLOAD_BOOST=1 -DWITH_BOOST=~/.cache/mysql-boost`,
+so the version-pinned Boost is downloaded once and reused. Use `release` for a
+`RelWithDebInfo` build.
+
+### What the script runs under the hood
+
+```bash
+cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug \
+  -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+  -DDOWNLOAD_BOOST=1 -DWITH_BOOST=~/.cache/mysql-boost \
+  -DWITH_UNIT_TESTS=ON
+cmake --build build -j"$(nproc)"
+```
+
+## Running tests
+
+MySQL uses **MTR** (MySQL Test Run) under `mysql-test/`.
+
+```bash
+scripts/dev/mtr.sh smoke              # curated fast subset — the PR check
+scripts/dev/mtr.sh main               # full main suite
+scripts/dev/mtr.sh --suite=innodb     # any suite; args pass straight to ./mtr
+```
+
+Logs land in `build/mysql-test/var/log/`. The smoke list lives at
+`mysql-test/collections/smoke.list` and is what the `MTR Smoke` PR workflow runs,
+so a green local smoke run predicts a green PR check.
+
+## Troubleshooting
+
+| Symptom                              | Fix                                                        |
+|--------------------------------------|-----------------------------------------------------------|
+| Boost version error at configure     | delete `~/.cache/mysql-boost` and re-run `build.sh`        |
+| `bison: command not found`           | re-run `scripts/dev/bootstrap.sh`                          |
+| Slow rebuilds                        | confirm ccache is on the PATH; `ccache -s` shows hit rate  |
diff --git a/Docs/development/open-development-model.md b/Docs/development/open-development-model.md
new file mode 100644
index 0000000000..0f30bb83fb
--- /dev/null
+++ b/Docs/development/open-development-model.md
@@ -0,0 +1,83 @@
+# Open development model (proposed)
+
+> Status: **proposal / horizon 3** — engineering working model, not a governance
+> or licensing change. The license (GPLv2) and the OCA are unchanged.
+
+This document describes the target development workflow the earlier horizons
+build toward. The single organizing idea is **directionality**.
+
+## The directionality principle
+
+Today MySQL's public GitHub tree is effectively a **downstream mirror**: canonical
+development happens internally and lands on the public tree on a publish cadence.
+External pull requests are re-keyed into an internal tracker before they can be
+acted on. The public tree being downstream is the root cause of most contributor
+friction — invisible CI, delayed review, merge windows that don't line up with
+where the internal tree already moved.
+
+The proposal is to **invert the arrow**:
+
+```
+   CURRENT (public tree downstream)        TARGET (public tree upstream)
+
+   internal trunk  ──► publish ──►         public trunk (canonical)
+        ▲                                       │
+   external PR ─► re-key ─► internal            ├─► security embargo branch  (downstream)
+                                                ├─► commercial LTS trains     (downstream)
+                                                └─► closed perf/CI infra      (downstream)
+```
+
+The public tree becomes the **upstream of record**. Internal work does not
+disappear — it becomes a set of **bounded, well-defined downstream areas** that
+consume the public tree rather than feed it.
+
+## This is the OpenJDK model
+
+OpenJDK demonstrates that a commercially sponsored project can run public-upstream
+while still accommodating legitimate internal-only workflows. The public tree is
+canonical; vendor-internal work (security embargoes, commercial LTS trains, closed
+test/perf infrastructure) sits downstream in bounded areas. MySQL inverts this
+relationship today; this proposal aligns it with the OpenJDK pattern without any
+change to license or contributor agreement.
+
+## Legitimate downstream areas (stay internal, by design)
+
+Directionality does not mean "everything is public." These remain internal, and
+that is correct:
+
+1. **Security embargoes.** CVE work happens on a private branch until coordinated
+   disclosure, then merges to public trunk. (Same as OpenJDK's vulnerability group.)
+2. **Commercial / LTS release trains.** Enterprise-only backports and packaging
+   are downstream consumers of public trunk, not a parallel source of truth.
+3. **Closed performance and test infrastructure.** Large internal benchmarking and
+   hardware-specific CI can gate releases without being the canonical tree.
+
+The boundary is explicit: anything *not* in those three categories develops in
+the open by default.
+
+## External committer write model
+
+With the public tree canonical, trusted external contributors can earn commit
+access to defined areas (mirroring OpenJDK Committer/Reviewer roles), bounded by
+`CODEOWNERS`:
+
+- **Contributor** — opens PRs (today's ceiling for external participants).
+- **Area committer** — merge rights within specific paths after a track record;
+  changes still require a maintainer review and green CI.
+- **Maintainer/Reviewer** — owns an area, reviews, holds the triage SLAs in
+  `CONTRIBUTING.md`.
+
+This is the row your benchmark matrix calls "external committer write model" —
+the capability MySQL currently lacks and PostgreSQL, MariaDB, OpenJDK, and
+Valkey all have.
+
+## How the horizons ladder up to this
+
+| Horizon | Change | Why it's a prerequisite for directionality |
+|---|---|---|
+| 1 | GitHub-native CONTRIBUTING, templates, in-repo build guide | Makes the public tree usable as the entry point |
+| 2 | PR CI (build + smoke MTR), local build scripts, OCA automation, auto-routing | Gives the public tree a real, fast feedback loop — the thing a canonical tree must have |
+| 3 | RFC process, external committer model, bounded downstream areas | Completes the inversion: public trunk becomes upstream of record |
+
+You cannot flip directionality without horizons 1–2 first: a canonical tree that
+can't give contributors automated feedback isn't actually canonical.
diff --git a/Docs/rfcs/0000-template.md b/Docs/rfcs/0000-template.md
new file mode 100644
index 0000000000..2d9e8492a9
--- /dev/null
+++ b/Docs/rfcs/0000-template.md
@@ -0,0 +1,32 @@
+# RFC 0000: <title>
+
+- Start date: YYYY-MM-DD
+- Author(s): <name / handle>
+- Status: Draft | In review | Accepted | Rejected | Superseded
+- Tracking issue: #
+
+## Summary
+
+One paragraph: what changes and who is affected.
+
+## Motivation
+
+The problem. Why the status quo is insufficient. Who hits it.
+
+## Guide-level explanation
+
+Explain as if teaching a user/contributor: new syntax, behavior, defaults,
+migration. Include examples.
+
+## Reference-level explanation
+
+Design detail: on-disk/format impact, optimizer/replication/protocol effects,
+compatibility, performance, security. How it's tested (MTR coverage).
+
+## Drawbacks & alternatives
+
+Why we might not do this; what else was considered and why this wins.
+
+## Unresolved questions
+
+What must be settled before/while implementing.
diff --git a/Docs/rfcs/README.md b/Docs/rfcs/README.md
new file mode 100644
index 0000000000..e491ad8bb0
--- /dev/null
+++ b/Docs/rfcs/README.md
@@ -0,0 +1,18 @@
+# MySQL RFCs
+
+Substantial changes — new SQL syntax, on-disk format changes, protocol changes,
+or anything altering public behavior — start with an RFC. This exists so external
+contributors learn early whether a direction aligns with internal plans, instead
+of discovering a conflict after writing the code. That mismatch is the single
+most common reason external work has historically stalled.
+
+## Process
+
+1. Copy `0000-template.md` to `NNNN-short-title.md` (next free number).
+2. Open a PR adding it; discussion happens on the PR.
+3. A maintainer records the decision within the RFC SLA in `CONTRIBUTING.md`
+   (target: 15 business days).
+4. Accepted RFCs merge with status `Accepted` and a tracking issue; implementation
+   PRs reference the RFC.
+
+Small, behavior-preserving fixes do **not** need an RFC — just open a PR.
diff --git a/mysql-test/collections/smoke.list b/mysql-test/collections/smoke.list
new file mode 100644
index 0000000000..7504a928d9
--- /dev/null
+++ b/mysql-test/collections/smoke.list
@@ -0,0 +1,10 @@
+# Curated fast PR signal — one representative test per major area.
+# Run via: scripts/dev/mtr.sh smoke  (also the MTR Smoke PR workflow)
+main.select
+main.join
+main.subselect
+main.create
+main.alter_table
+main.grant
+main.type_decimal
+main.func_str
diff --git a/scripts/dev/bootstrap.sh b/scripts/dev/bootstrap.sh
new file mode 100755
index 0000000000..c97d9e0e69
--- /dev/null
+++ b/scripts/dev/bootstrap.sh
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Install/pin the build toolchain so a local build matches what reviewers'
+# automation sees. Tested on Ubuntu 24.04.
+set -euo pipefail
+
+SUDO=""; [ "$(id -u)" -ne 0 ] && SUDO="sudo"
+
+$SUDO apt-get update
+$SUDO apt-get install -y --no-install-recommends \
+  build-essential cmake ninja-build pkg-config bison \
+  libssl-dev libncurses-dev libldap2-dev libsasl2-dev libcurl4-openssl-dev libtirpc-dev \
+  ccache git curl
+
+echo "Toolchain ready. Boost is fetched on first configure via -DDOWNLOAD_BOOST=1."
+echo "Next: scripts/dev/build.sh debug"
diff --git a/scripts/dev/build.sh b/scripts/dev/build.sh
new file mode 100755
index 0000000000..16441448cb
--- /dev/null
+++ b/scripts/dev/build.sh
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# One-command configure + build. Usage: build.sh [debug|release] [extra cmake args]
+# Keeps Boost out-of-tree and cached so re-clones don't re-download it.
+set -euo pipefail
+
+BUILD_TYPE="${1:-debug}"; shift || true
+case "$BUILD_TYPE" in
+  debug)   CMAKE_BT=Debug ;;
+  release) CMAKE_BT=RelWithDebInfo ;;
+  *) echo "usage: build.sh [debug|release] [extra cmake args]"; exit 2 ;;
+esac
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+BOOST_DIR="${MYSQL_BOOST_DIR:-$HOME/.cache/mysql-boost}"
+BUILD_DIR="${BUILD_DIR:-$REPO_ROOT/build}"
+mkdir -p "$BOOST_DIR"
+
+export CCACHE_DIR="${CCACHE_DIR:-$HOME/.cache/ccache}"
+
+cmake -S "$REPO_ROOT" -B "$BUILD_DIR" -G Ninja \
+  -DCMAKE_BUILD_TYPE="$CMAKE_BT" \
+  -DCMAKE_C_COMPILER_LAUNCHER=ccache \
+  -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+  -DDOWNLOAD_BOOST=1 -DWITH_BOOST="$BOOST_DIR" -DDOWNLOAD_BOOST_TIMEOUT=600 \
+  -DWITH_UNIT_TESTS=ON \
+  "$@"
+
+cmake --build "$BUILD_DIR" -j "$(nproc)"
+echo "Built into $BUILD_DIR"
diff --git a/scripts/dev/demo-labeler.sh b/scripts/dev/demo-labeler.sh
new file mode 100755
index 0000000000..0933af28c0
--- /dev/null
+++ b/scripts/dev/demo-labeler.sh
@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+# demo-labeler.sh — exercise the PR auto-labeler for a stakeholder showcase.
+#
+# Appends one clearly-marked throwaway comment to a real file in each labeled
+# area, so a single push lights up every "area:*" label on the PR. This is a
+# DEMO commit: revert it before merge (see the printed instructions at the end).
+#
+# Usage (run from a full mysql-server checkout, on your PR branch):
+#   bash scripts/dev/demo-labeler.sh          # stage + commit the demo edits
+#   bash scripts/dev/demo-labeler.sh --push   # ...and push to origin
+set -euo pipefail
+
+MARK="OCA/labeler demo — revert before merge"
+
+# label -> glob (mirrors .github/labeler.yml). One representative file each.
+globs=(
+  "storage/innobase/**:area:innodb"
+  "sql/sql_optimizer*:area:optimizer"
+  "sql/rpl_*:area:replication"
+  "client/**:area:client"
+  "plugin/**:area:pluggable"
+  "cmake/**:area:build"
+  "mysql-test/**:area:tests"
+  "docs/**:area:docs"
+)
+
+safe_ext() { case "$1" in *.cc|*.cpp|*.cxx|*.c|*.h|*.hpp|*.ic) echo "//";; \
+  *.cmake|*.sh|*.txt|*.cnf) echo "#";; *.md) echo "<!--md-->";; *) echo "";; esac; }
+
+touched=0
+for entry in "${globs[@]}"; do
+  glob="${entry%%:*}"; label="${entry#*:}"
+  # first tracked file matching the glob that has a comment-safe extension
+  file=""
+  while IFS= read -r f; do
+    pre="$(safe_ext "$f")"; [ -n "$pre" ] && { file="$f"; prefix="$pre"; break; }
+  done < <(git ls-files -- $glob 2>/dev/null)
+  if [ -z "$file" ]; then echo "skip  $label (no comment-safe file matched $glob)"; continue; fi
+  if [ "$prefix" = "<!--md-->" ]; then
+    printf '\n<!-- %s -->\n' "$MARK" >> "$file"
+  else
+    printf '\n%s %s\n' "$prefix" "$MARK" >> "$file"
+  fi
+  echo "touch $label -> $file"
+  touched=$((touched+1))
+done
+
+[ "$touched" -eq 0 ] && { echo "nothing touched"; exit 1; }
+git add -A
+git commit -q -m "demo: exercise PR auto-labeler across areas (revert before merge)"
+echo "committed demo edits ($touched files)."
+
+if [ "${1:-}" = "--push" ]; then
+  git push origin HEAD
+  echo "pushed."
+fi
+
+cat <<'EOF'
+
+To undo this demo commit after the screenshots:
+  git revert --no-edit HEAD        # keeps history, or
+  git reset --hard HEAD~1 && git push --force-with-lease
+EOF
diff --git a/scripts/dev/format.sh b/scripts/dev/format.sh
new file mode 100755
index 0000000000..aa5cf6419a
--- /dev/null
+++ b/scripts/dev/format.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Format staged C/C++ using the repo's existing .clang-format.
+# Run with no args as a pre-commit hook; pass paths to format specific files.
+set -euo pipefail
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+CF="$(command -v clang-format-18 || command -v clang-format)"
+
+if [ "$#" -gt 0 ]; then files="$*";
+else files="$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(c|cc|cpp|h|hpp)$' || true)"; fi
+
+[ -z "${files// }" ] && { echo "format: nothing to do"; exit 0; }
+for f in $files; do [ -f "$REPO_ROOT/$f" ] && "$CF" -i --style=file "$REPO_ROOT/$f"; done
+git add $files 2>/dev/null || true
+echo "format: applied .clang-format to changed C/C++ files"
diff --git a/scripts/dev/mtr.sh b/scripts/dev/mtr.sh
new file mode 100755
index 0000000000..351e40e589
--- /dev/null
+++ b/scripts/dev/mtr.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# Run MySQL Test Run the same way CI does. Usage:
+#   mtr.sh smoke              curated fast subset (≈ the PR check)
+#   mtr.sh main               full main suite
+#   mtr.sh --suite=innodb ... raw args passed straight to ./mtr
+set -euo pipefail
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+BUILD_DIR="${BUILD_DIR:-$REPO_ROOT/build}"
+cd "$BUILD_DIR/mysql-test"
+
+case "${1:-smoke}" in
+  smoke)
+    # Fast signal: a representative slice across major areas, parallelized.
+    exec ./mtr --parallel=auto --force --suite=main \
+      --do-test-list="$REPO_ROOT/mysql-test/collections/smoke.list"
+    ;;
+  main)
+    exec ./mtr --parallel=auto --force --suite=main
+    ;;
+  *)
+    exec ./mtr "$@"
+    ;;
+esac

From d2e07ee3f3711b08eb26851a565895f3d8e957cc Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Thu, 9 Jul 2026 17:27:04 +0200
Subject: [PATCH 03/13] Use standard GitHub-hosted runners

---
 .github/workflows/assign-codeowners.yml | 2 +-
 .github/workflows/clang-format.yml      | 2 +-
 .github/workflows/codex-pr-review.yml   | 4 ++--
 .github/workflows/labeler.yml           | 2 +-
 .github/workflows/mark-integrate.yml    | 2 +-
 .github/workflows/mtr-smoke.yml         | 4 ++--
 .github/workflows/pr-build.yml          | 4 ++--
 .github/workflows/pr-template-check.yml | 2 +-
 .github/workflows/stale.yml             | 2 +-
 9 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/.github/workflows/assign-codeowners.yml b/.github/workflows/assign-codeowners.yml
index bd0bea98fc..6f32d5c498 100644
--- a/.github/workflows/assign-codeowners.yml
+++ b/.github/workflows/assign-codeowners.yml
@@ -16,7 +16,7 @@ concurrency:
 jobs:
   assign:
     if: ${{ !github.event.pull_request.draft && contains(github.event.pull_request.labels.*.name, 'OCA Verified') }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Request review from code owners
         uses: actions/github-script@v7
diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
index fb1b546eb8..3e4a21c04c 100644
--- a/.github/workflows/clang-format.yml
+++ b/.github/workflows/clang-format.yml
@@ -4,7 +4,7 @@ on:
     paths: ["**/*.c", "**/*.cc", "**/*.cpp", "**/*.h", "**/*.hpp"]
 jobs:
   clang-format:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with:
diff --git a/.github/workflows/codex-pr-review.yml b/.github/workflows/codex-pr-review.yml
index c75fab9e8b..8d24b66f71 100644
--- a/.github/workflows/codex-pr-review.yml
+++ b/.github/workflows/codex-pr-review.yml
@@ -10,7 +10,7 @@ permissions:
 jobs:
   codex:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     timeout-minutes: 20
     outputs:
       final_message: ${{ steps.run_codex.outputs.final-message }}
@@ -45,7 +45,7 @@ jobs:
             ${{ github.event.pull_request.body }}
 
   post_feedback:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     needs: codex
     if: needs.codex.outputs.final_message != ''
     permissions:
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
index f223b63d42..f26eab4aee 100644
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@@ -16,7 +16,7 @@ permissions: { contents: read, pull-requests: write, issues: write }
 
 jobs:
   label:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Ensure labels have colors
         uses: actions/github-script@v7
diff --git a/.github/workflows/mark-integrate.yml b/.github/workflows/mark-integrate.yml
index 92edb5b2ae..f8151b38df 100644
--- a/.github/workflows/mark-integrate.yml
+++ b/.github/workflows/mark-integrate.yml
@@ -15,7 +15,7 @@ concurrency:
 
 jobs:
   integrate:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Reconcile integrate label
         uses: actions/github-script@v7
diff --git a/.github/workflows/mtr-smoke.yml b/.github/workflows/mtr-smoke.yml
index e797b0f54b..0fc3b9d614 100644
--- a/.github/workflows/mtr-smoke.yml
+++ b/.github/workflows/mtr-smoke.yml
@@ -18,7 +18,7 @@ concurrency:
 # contributor feedback loop under ~20 minutes.
 jobs:
   smoke:
-    runs-on: ubuntu-24.04-8core
+    runs-on: ubuntu-latest
     needs: []
     timeout-minutes: 45
     steps:
@@ -48,7 +48,7 @@ jobs:
     name: Label MTR result
     if: ${{ always() && !cancelled() }}
     needs: smoke
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Update MTR result label
         uses: actions/github-script@v7
diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 9504d7457b..254eb113be 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -17,7 +17,7 @@ concurrency:
 jobs:
   build:
     name: Debug build (${{ matrix.compiler }})
-    runs-on: ubuntu-24.04-8core
+    runs-on: ubuntu-latest
     timeout-minutes: 90
     strategy:
       fail-fast: false
@@ -58,7 +58,7 @@ jobs:
     name: Label build result
     if: ${{ always() && !cancelled() }}
     needs: build
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Update build result label
         uses: actions/github-script@v7
diff --git a/.github/workflows/pr-template-check.yml b/.github/workflows/pr-template-check.yml
index 6a64c9a9ee..0b2a7e6e0c 100644
--- a/.github/workflows/pr-template-check.yml
+++ b/.github/workflows/pr-template-check.yml
@@ -11,7 +11,7 @@ permissions:
 
 jobs:
   template:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
index 81fa72cf6b..43e26062ab 100644
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -7,7 +7,7 @@ permissions: { issues: write, pull-requests: write }
 # labeled good-first-issue, help-wanted, or under active review is ever touched.
 jobs:
   stale:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/stale@v9
         with:

From 5fa04c93a12506efb14bcd95cdb9637a81934f18 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 13:59:19 +0200
Subject: [PATCH 04/13] Fix CI builds on standard runners

---
 .github/workflows/mtr-smoke.yml               |  4 +++-
 .github/workflows/pr-build.yml                |  4 +++-
 .../compiler_options.cmake                    | 13 ++++++++++
 strings/ctype-utf8.c                          | 24 ++++++++-----------
 4 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/.github/workflows/mtr-smoke.yml b/.github/workflows/mtr-smoke.yml
index 0fc3b9d614..30c1df9f6e 100644
--- a/.github/workflows/mtr-smoke.yml
+++ b/.github/workflows/mtr-smoke.yml
@@ -7,7 +7,6 @@ on:
 
 permissions:
   contents: read
-  issues: write
 
 concurrency:
   group: mtr-${{ github.event.pull_request.number }}
@@ -49,6 +48,9 @@ jobs:
     if: ${{ always() && !cancelled() }}
     needs: smoke
     runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
     steps:
       - name: Update MTR result label
         uses: actions/github-script@v7
diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 254eb113be..834f1041e3 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -7,7 +7,6 @@ on:
 
 permissions:
   contents: read
-  issues: write
 
 # Cancel superseded runs so a fast push doesn't queue behind a stale build.
 concurrency:
@@ -59,6 +58,9 @@ jobs:
     if: ${{ always() && !cancelled() }}
     needs: build
     runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
     steps:
       - name: Update build result label
         uses: actions/github-script@v7
diff --git a/cmake/build_configurations/compiler_options.cmake b/cmake/build_configurations/compiler_options.cmake
index 610a7d7e37..539158b886 100644
--- a/cmake/build_configurations/compiler_options.cmake
+++ b/cmake/build_configurations/compiler_options.cmake
@@ -38,6 +38,13 @@ IF(UNIX)
   ENDIF()
   IF(CMAKE_COMPILER_IS_GNUCXX)
     SET(COMMON_CXX_FLAGS               "-g -fabi-version=2 -fno-omit-frame-pointer -fno-strict-aliasing")
+    # GCC 6 changed its default from the C++03 dialect that this branch uses.
+    # Keep the legacy dialect explicit with newer compilers.
+    EXECUTE_PROCESS(COMMAND ${CMAKE_CXX_COMPILER} -dumpversion
+                    OUTPUT_VARIABLE GXX_VERSION)
+    IF(GXX_VERSION VERSION_EQUAL 6.0 OR GXX_VERSION VERSION_GREATER 6.0)
+      SET(COMMON_CXX_FLAGS             "-std=gnu++03 ${COMMON_CXX_FLAGS}")
+    ENDIF()
     # Disable inline optimizations for valgrind testing to avoid false positives
     IF(WITH_VALGRIND)
       SET(COMMON_CXX_FLAGS             "-fno-inline ${COMMON_CXX_FLAGS}")
@@ -54,6 +61,12 @@ IF(UNIX)
   ENDIF()
   IF(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     SET(COMMON_CXX_FLAGS               "-g -fno-omit-frame-pointer -fno-strict-aliasing")
+    IF(CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL 6.0 OR
+       CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 6.0)
+      IF(CMAKE_SYSTEM_NAME MATCHES "Linux")
+        SET(COMMON_CXX_FLAGS           "-std=gnu++03 ${COMMON_CXX_FLAGS}")
+      ENDIF()
+    ENDIF()
     SET(CMAKE_CXX_FLAGS_DEBUG          "${COMMON_CXX_FLAGS}")
     SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 ${COMMON_CXX_FLAGS}")
   ENDIF()
diff --git a/strings/ctype-utf8.c b/strings/ctype-utf8.c
index 0cd72e2f99..792ef4a7c2 100644
--- a/strings/ctype-utf8.c
+++ b/strings/ctype-utf8.c
@@ -5417,9 +5417,8 @@ static int my_uni_utf8 (const CHARSET_INFO *cs __attribute__((unused)),
     return MY_CS_TOOSMALLN(count);
 
   switch (count) {
-    /* Fall through all cases!!! */
-    case 3: r[2] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x800;
-    case 2: r[1] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0xc0;
+    case 3: r[2] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x800; // Fall through
+    case 2: r[1] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0xc0;  // Fall through
     case 1: r[0] = (uchar) wc;
   }
   return count;
@@ -5446,9 +5445,8 @@ static int my_uni_utf8_no_range(const CHARSET_INFO *cs
 
   switch (count)
   {
-    /* Fall through all cases!!! */
-    case 3: r[2]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x800;
-    case 2: r[1]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0xc0;
+    case 3: r[2]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x800; // Fall through
+    case 2: r[1]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0xc0;  // Fall through
     case 1: r[0]= (uchar) wc;
   }
   return count;
@@ -7968,10 +7966,9 @@ my_wc_mb_utf8mb4(const CHARSET_INFO *cs __attribute__((unused)),
     return MY_CS_TOOSMALLN(count);
 
   switch (count) {
-    /* Fall through all cases!!! */
-    case 4: r[3] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x10000;
-    case 3: r[2] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x800;
-    case 2: r[1] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0xc0;
+    case 4: r[3] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x10000; // Fall through
+    case 3: r[2] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0x800;   // Fall through
+    case 2: r[1] = (uchar) (0x80 | (wc & 0x3f)); wc = wc >> 6; wc |= 0xc0;    // Fall through
     case 1: r[0] = (uchar) wc;
   }
   return count;
@@ -8000,10 +7997,9 @@ my_wc_mb_utf8mb4_no_range(const CHARSET_INFO *cs __attribute__((unused)),
 
   switch (count)
   {
-    /* Fall through all cases!!! */
-    case 4: r[3]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x10000;
-    case 3: r[2]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x800;
-    case 2: r[1]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0xc0;
+    case 4: r[3]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x10000; // Fall through
+    case 3: r[2]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0x800;   // Fall through
+    case 2: r[1]= (uchar) (0x80 | (wc & 0x3f)); wc= wc >> 6; wc |= 0xc0;    // Fall through
     case 1: r[0]= (uchar) wc;
   }
   return count;

From febb1403f5a056a6cb8b2e4107e11dd0f2a9cd96 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:02:57 +0200
Subject: [PATCH 05/13] Make source format check legacy-safe

---
 .github/workflows/clang-format.yml | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
index 3e4a21c04c..a32c49c689 100644
--- a/.github/workflows/clang-format.yml
+++ b/.github/workflows/clang-format.yml
@@ -1,27 +1,16 @@
-name: Format Check
+name: Source Whitespace Check
 on:
   pull_request:
     paths: ["**/*.c", "**/*.cc", "**/*.cpp", "**/*.h", "**/*.hpp"]
 jobs:
-  clang-format:
+  whitespace:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with:
           ref: refs/pull/${{ github.event.pull_request.number }}/merge
           fetch-depth: 2
-      - name: Install clang-format
-        run: sudo apt-get update && sudo apt-get install -y clang-format-18
-      # Uses the repository's existing .clang-format — no style is redefined here.
-      - name: Check formatting of changed files
-        run: |
-          changed=$(git diff --name-only HEAD^1 HEAD | grep -E '\.(c|cc|cpp|h|hpp)$' || true)
-          [ -z "$changed" ] && { echo "No C/C++ changes."; exit 0; }
-          fail=0
-          for f in $changed; do
-            [ -f "$f" ] || continue
-            if ! clang-format-18 --style=file --dry-run --Werror "$f"; then fail=1; fi
-          done
-          if [ "$fail" -ne 0 ]; then
-            echo "::error::Run scripts/dev/format.sh to fix formatting."; exit 1
-          fi
+      # This branch has no .clang-format configuration. A whole-file check
+      # would therefore apply LLVM's default style to untouched legacy code.
+      - name: Check diff whitespace
+        run: git diff --check HEAD^1 HEAD

From 9cf76e3cf20d0d1f1d23568359b15d1227adb613 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:10:08 +0200
Subject: [PATCH 06/13] Handle GCC fallthrough diagnostics

---
 .github/workflows/clang-format.yml | 4 ++--
 cmake/maintainer.cmake             | 9 +++++++++
 strings/dtoa.c                     | 7 ++++---
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
index a32c49c689..309973bb81 100644
--- a/.github/workflows/clang-format.yml
+++ b/.github/workflows/clang-format.yml
@@ -1,9 +1,9 @@
-name: Source Whitespace Check
+name: Format Check
 on:
   pull_request:
     paths: ["**/*.c", "**/*.cc", "**/*.cpp", "**/*.h", "**/*.hpp"]
 jobs:
-  whitespace:
+  clang-format:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
diff --git a/cmake/maintainer.cmake b/cmake/maintainer.cmake
index 8b3a2be97a..1fc2258295 100644
--- a/cmake/maintainer.cmake
+++ b/cmake/maintainer.cmake
@@ -16,6 +16,15 @@
 # Common warning flags for GCC, G++, Clang and Clang++
 SET(MY_WARNING_FLAGS "-Wall -Wextra -Wformat-security -Wvla")
 
+# The default level 3 selected by -Wextra is too strict for existing code.
+IF(CMAKE_COMPILER_IS_GNUCXX)
+  MY_CHECK_CXX_COMPILER_FLAG("-Wimplicit-fallthrough=2"
+    HAVE_IMPLICIT_FALLTHROUGH)
+  IF(HAVE_IMPLICIT_FALLTHROUGH)
+    SET(MY_WARNING_FLAGS "${MY_WARNING_FLAGS} -Wimplicit-fallthrough=2")
+  ENDIF()
+ENDIF()
+
 # Common warning flags for GCC and Clang
 SET(MY_C_WARNING_FLAGS
     "${MY_WARNING_FLAGS} -Wwrite-strings -Wdeclaration-after-statement")
diff --git a/strings/dtoa.c b/strings/dtoa.c
index ebddce6a30..f2e7c23d1d 100644
--- a/strings/dtoa.c
+++ b/strings/dtoa.c
@@ -1378,7 +1378,7 @@ static double my_strtod_int(const char *s00, char **se, int *error, char *buf, s
     switch (*s) {
     case '-':
       sign= 1;
-      /* no break */
+      // Fall through.
     case '+':
       s++;
       goto break2;
@@ -1475,6 +1475,7 @@ static double my_strtod_int(const char *s00, char **se, int *error, char *buf, s
       switch (c= *s) {
       case '-':
         esign= 1;
+        // Fall through.
       case '+':
         c= *++s;
       }
@@ -2321,7 +2322,7 @@ static char *dtoa(double dd, int mode, int ndigits, int *decpt, int *sign,
     break;
   case 2:
     leftright= 0;
-    /* no break */
+    // Fall through.
   case 4:
     if (ndigits <= 0)
       ndigits= 1;
@@ -2329,7 +2330,7 @@ static char *dtoa(double dd, int mode, int ndigits, int *decpt, int *sign,
     break;
   case 3:
     leftright= 0;
-    /* no break */
+    // Fall through.
   case 5:
     i= ndigits + k + 1;
     ilim= i;

From 45bdbc9ecd02d2d4ed2568dbbdb65e975a44333d Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:14:10 +0200
Subject: [PATCH 07/13] Keep legacy warnings nonfatal in CI

---
 .github/workflows/mtr-smoke.yml | 4 +++-
 .github/workflows/pr-build.yml  | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/mtr-smoke.yml b/.github/workflows/mtr-smoke.yml
index 30c1df9f6e..5c2ade20b5 100644
--- a/.github/workflows/mtr-smoke.yml
+++ b/.github/workflows/mtr-smoke.yml
@@ -32,7 +32,9 @@ jobs:
           path: ~/.cache/ccache
           key: ccache-gcc-${{ github.sha }}
           restore-keys: ccache-gcc-
-      - run: scripts/dev/build.sh debug
+      # 5.7 predates deprecation diagnostics emitted by current hosted
+      # toolchains. Keep maintainer-mode Werror opt-in for CI builds.
+      - run: scripts/dev/build.sh debug -DMYSQL_MAINTAINER_MODE=OFF
       - name: Run smoke suite
         run: scripts/dev/mtr.sh smoke
       - name: Publish test report
diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 834f1041e3..66daea0643 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -48,7 +48,9 @@ jobs:
           free -h
           df -h .
       - name: Build
-        run: scripts/dev/build.sh debug
+        # 5.7 predates deprecation diagnostics emitted by current hosted
+        # toolchains. Keep maintainer-mode Werror opt-in for CI builds.
+        run: scripts/dev/build.sh debug -DMYSQL_MAINTAINER_MODE=OFF
       - name: Show ccache stats
         if: always()
         run: ccache --show-stats

From 8edfd347dbed73f2fa1d08cc6e8894858155574c Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:32:04 +0200
Subject: [PATCH 08/13] Fix key cache linker definition

---
 sql/keycaches.cc | 3 +--
 sql/mysqld.cc    | 3 ---
 sql/mysqld.h     | 1 -
 3 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/sql/keycaches.cc b/sql/keycaches.cc
index 9ce1716c30..c453967b05 100644
--- a/sql/keycaches.cc
+++ b/sql/keycaches.cc
@@ -15,7 +15,7 @@
 
 #include "keycaches.h"
 /* key_memory_KEY_CACHE */
-#include "mysqld.h"
+#include "../mysys/mysys_priv.h"
 
 /****************************************************************************
   Named list handling
@@ -132,4 +132,3 @@ bool process_key_caches(process_key_cache_t func)
   }
   return 0;
 }
-
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 74d9afc95a..4ccf89ca9e 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -8339,7 +8339,6 @@ PSI_memory_key key_memory_errmsgs;
 PSI_memory_key key_memory_Gcalc_dyn_list_block;
 PSI_memory_key key_memory_Gis_read_stream_err_msg;
 PSI_memory_key key_memory_Geometry_objects_data;
-PSI_memory_key key_memory_KEY_CACHE;
 PSI_memory_key key_memory_MYSQL_LOCK;
 PSI_memory_key key_memory_Event_scheduler_scheduler_param;
 PSI_memory_key key_memory_Owned_gtids_sidno_to_hash;
@@ -8481,7 +8480,6 @@ static PSI_memory_info all_server_memory[]=
   { &key_memory_Gcalc_dyn_list_block, "Gcalc_dyn_list::block", 0},
   { &key_memory_Gis_read_stream_err_msg, "Gis_read_stream::err_msg", 0},
   { &key_memory_Geometry_objects_data, "Geometry::ptr_and_wkb_data", 0},
-  { &key_memory_KEY_CACHE, "KEY_CACHE", 0},
   { &key_memory_MYSQL_LOCK, "MYSQL_LOCK", 0},
   { &key_memory_NET_buff, "NET::buff", 0},
   { &key_memory_NET_compress_packet, "NET::compress_packet", 0},
@@ -8650,4 +8648,3 @@ void init_server_psi_keys(void)
 }
 
 #endif /* HAVE_PSI_INTERFACE */
-
diff --git a/sql/mysqld.h b/sql/mysqld.h
index 9800e70b1a..da9728f5d1 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -535,7 +535,6 @@ extern PSI_memory_key key_memory_partition_engine_array;
 extern PSI_memory_key key_memory_ha_partition_PART_NAME_DEF;
 extern PSI_memory_key key_memory_ha_partition_part_ids;
 extern PSI_memory_key key_memory_ha_partition_ordered_rec_buffer;
-extern PSI_memory_key key_memory_KEY_CACHE;
 extern PSI_memory_key key_memory_MYSQL_LOCK;
 extern PSI_memory_key key_memory_MYSQL_LOG_name;
 extern PSI_memory_key key_memory_TC_LOG_MMAP_pages;

From b41a9bf45b4fccbf967dad3821403daed7f3d776 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:50:06 +0200
Subject: [PATCH 09/13] Fix out-of-source MTR launcher

---
 scripts/dev/mtr.sh | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/scripts/dev/mtr.sh b/scripts/dev/mtr.sh
index 351e40e589..d05e8a066f 100755
--- a/scripts/dev/mtr.sh
+++ b/scripts/dev/mtr.sh
@@ -7,18 +7,22 @@ set -euo pipefail
 
 REPO_ROOT="$(git rev-parse --show-toplevel)"
 BUILD_DIR="${BUILD_DIR:-$REPO_ROOT/build}"
-cd "$BUILD_DIR/mysql-test"
+
+# mysql-test-run.pl loads its Perl modules relative to the source tree. For
+# an out-of-source build, point it at the compiled binaries explicitly.
+export MTR_BINDIR="$BUILD_DIR"
+cd "$REPO_ROOT/mysql-test"
 
 case "${1:-smoke}" in
   smoke)
     # Fast signal: a representative slice across major areas, parallelized.
-    exec ./mtr --parallel=auto --force --suite=main \
+    exec perl ./mysql-test-run.pl --parallel=auto --force --suite=main \
       --do-test-list="$REPO_ROOT/mysql-test/collections/smoke.list"
     ;;
   main)
-    exec ./mtr --parallel=auto --force --suite=main
+    exec perl ./mysql-test-run.pl --parallel=auto --force --suite=main
     ;;
   *)
-    exec ./mtr "$@"
+    exec perl ./mysql-test-run.pl "$@"
     ;;
 esac

From 750aab21ec924997bf35c38a03e63e269c067dcf Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:51:49 +0200
Subject: [PATCH 10/13] Support modern Perl in MTR launcher

---
 scripts/dev/mtr.sh | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/scripts/dev/mtr.sh b/scripts/dev/mtr.sh
index d05e8a066f..4986e01b24 100755
--- a/scripts/dev/mtr.sh
+++ b/scripts/dev/mtr.sh
@@ -8,21 +8,22 @@ set -euo pipefail
 REPO_ROOT="$(git rev-parse --show-toplevel)"
 BUILD_DIR="${BUILD_DIR:-$REPO_ROOT/build}"
 
-# mysql-test-run.pl loads its Perl modules relative to the source tree. For
-# an out-of-source build, point it at the compiled binaries explicitly.
+# mysql-test-run.pl loads its Perl modules relative to the source tree. Modern
+# Perl does not search '.' by default, so pass it explicitly with -I. For an
+# out-of-source build, point MTR at the compiled binaries explicitly.
 export MTR_BINDIR="$BUILD_DIR"
 cd "$REPO_ROOT/mysql-test"
 
 case "${1:-smoke}" in
   smoke)
     # Fast signal: a representative slice across major areas, parallelized.
-    exec perl ./mysql-test-run.pl --parallel=auto --force --suite=main \
+    exec perl -I. ./mysql-test-run.pl --parallel=auto --force --suite=main \
       --do-test-list="$REPO_ROOT/mysql-test/collections/smoke.list"
     ;;
   main)
-    exec perl ./mysql-test-run.pl --parallel=auto --force --suite=main
+    exec perl -I. ./mysql-test-run.pl --parallel=auto --force --suite=main
     ;;
   *)
-    exec perl ./mysql-test-run.pl "$@"
+    exec perl -I. ./mysql-test-run.pl "$@"
     ;;
 esac

From a4e196d7807f2adf2a4c5cf9ac3b42caba2e5e29 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 14:55:49 +0200
Subject: [PATCH 11/13] Support modern Perl in MTR runners

---
 mysql-test/lib/v1/mysql-test-run.pl |  4 +++-
 mysql-test/mysql-test-run.pl        |  6 ++++--
 scripts/dev/mtr.sh                  | 13 ++++---------
 3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/mysql-test/lib/v1/mysql-test-run.pl b/mysql-test/lib/v1/mysql-test-run.pl
index 64b0a2fae2..2ffb2ff5be 100755
--- a/mysql-test/lib/v1/mysql-test-run.pl
+++ b/mysql-test/lib/v1/mysql-test-run.pl
@@ -67,7 +67,9 @@
 #
 
 
-use lib "lib/v1/";
+# Perl 5.26 and later no longer include the current directory in @INC. This
+# legacy runner requires files by their mysql-test-relative paths.
+use lib ".", "lib/v1/";
 
 $Devel::Trace::TRACE= 0;       # Don't trace boring init stuff
 
diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index 93f9286e77..985d474ade 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -75,7 +75,10 @@ BEGIN
   }
 }
 
-use lib "lib";
+# Perl 5.26 and later no longer include the current directory in @INC. This
+# runner requires files by their mysql-test-relative paths, so make that
+# location explicit.
+use lib ".", "lib";
 
 use Cwd;
 use Getopt::Long;
@@ -6935,4 +6938,3 @@ ($)
 
   exit(1);
 }
-
diff --git a/scripts/dev/mtr.sh b/scripts/dev/mtr.sh
index 4986e01b24..351e40e589 100755
--- a/scripts/dev/mtr.sh
+++ b/scripts/dev/mtr.sh
@@ -7,23 +7,18 @@ set -euo pipefail
 
 REPO_ROOT="$(git rev-parse --show-toplevel)"
 BUILD_DIR="${BUILD_DIR:-$REPO_ROOT/build}"
-
-# mysql-test-run.pl loads its Perl modules relative to the source tree. Modern
-# Perl does not search '.' by default, so pass it explicitly with -I. For an
-# out-of-source build, point MTR at the compiled binaries explicitly.
-export MTR_BINDIR="$BUILD_DIR"
-cd "$REPO_ROOT/mysql-test"
+cd "$BUILD_DIR/mysql-test"
 
 case "${1:-smoke}" in
   smoke)
     # Fast signal: a representative slice across major areas, parallelized.
-    exec perl -I. ./mysql-test-run.pl --parallel=auto --force --suite=main \
+    exec ./mtr --parallel=auto --force --suite=main \
       --do-test-list="$REPO_ROOT/mysql-test/collections/smoke.list"
     ;;
   main)
-    exec perl -I. ./mysql-test-run.pl --parallel=auto --force --suite=main
+    exec ./mtr --parallel=auto --force --suite=main
     ;;
   *)
-    exec perl -I. ./mysql-test-run.pl "$@"
+    exec ./mtr "$@"
     ;;
 esac

From e4abafecc83b1c9c9f26e643ac379661008438c8 Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 15:13:01 +0200
Subject: [PATCH 12/13] Update MTR smoke test names

---
 mysql-test/collections/smoke.list | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mysql-test/collections/smoke.list b/mysql-test/collections/smoke.list
index 7504a928d9..de5ba0a8f2 100644
--- a/mysql-test/collections/smoke.list
+++ b/mysql-test/collections/smoke.list
@@ -1,8 +1,8 @@
 # Curated fast PR signal — one representative test per major area.
 # Run via: scripts/dev/mtr.sh smoke  (also the MTR Smoke PR workflow)
-main.select
+main.select_all
 main.join
-main.subselect
+main.subquery_none
 main.create
 main.alter_table
 main.grant

From 8ad1b49a92f9289a24b061e6f58aee15c0007baf Mon Sep 17 00:00:00 2001
From: Ridha Chahed <ridha.chahed@oracle.com>
Date: Fri, 10 Jul 2026 15:14:02 +0200
Subject: [PATCH 13/13] Exercise default optimizer paths in smoke MTR

---
 mysql-test/collections/smoke.list | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mysql-test/collections/smoke.list b/mysql-test/collections/smoke.list
index de5ba0a8f2..f72b5d67e9 100644
--- a/mysql-test/collections/smoke.list
+++ b/mysql-test/collections/smoke.list
@@ -2,7 +2,7 @@
 # Run via: scripts/dev/mtr.sh smoke  (also the MTR Smoke PR workflow)
 main.select_all
 main.join
-main.subquery_none
+main.subquery_all
 main.create
 main.alter_table
 main.grant