From fce22fcfe82bdc7a63a8636484806cc987286538 Mon Sep 17 00:00:00 2001
From: Evgeniy Patlan <evgeniy.patlan@percona.com>
Date: Wed, 19 Aug 2026 13:00:22 +0300
Subject: [PATCH] Relax warnings-as-errors on the parser plugin link line

The generated bison parsers already build with -Wno-error because they are
generated code the project does not control. With LTO enabled the compiler
diagnoses them again at link time, where per-source COMPILE_FLAGS no longer
apply, so the global -Werror makes those diagnostics fatal.

This is what breaks Debian and Ubuntu builds, which enable -flto=auto by
default: sql_yacc.cc and sql_hints.yy.cc each define a file-scope
enum yysymbol_kind_t with different enumerators, and -Wodr reports the
resulting ODR violation as an error:

  sql_yacc.cc:104:6: error: type 'yysymbol_kind_t' violates the C++ One
  Definition Rule [-Werror=odr]
  lto1: all warnings being treated as errors

Apply the same relaxation to the link line that the sources already get.
---
 mysqlshdk/libs/yparser/mysql/CMakeLists.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mysqlshdk/libs/yparser/mysql/CMakeLists.txt b/mysqlshdk/libs/yparser/mysql/CMakeLists.txt
index 3eaec7060..eee35419f 100644
--- a/mysqlshdk/libs/yparser/mysql/CMakeLists.txt
+++ b/mysqlshdk/libs/yparser/mysql/CMakeLists.txt
@@ -188,6 +188,13 @@ function(create_parser_plugin)
 
     # create the plugin
     add_library(${PLUGIN_NAME} MODULE ${MYSQL_SOURCES} ${PLUGIN_SOURCES})
+
+    # The generated parser sources are diagnosed again at link time when LTO is
+    # enabled, where the per-source COMPILE_FLAGS above no longer apply, so
+    # relax warnings on the link line as well
+    if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+        target_link_options(${PLUGIN_NAME} PRIVATE "-Wno-error")
+    endif()
     target_compile_definitions(${PLUGIN_NAME} PRIVATE
         "BUILDING_PARSER_PLUGIN"
         "PARSER_VERSION=\"${ARG_VERSION}\""