Bug #81351 switching session type from classic to JS fails
Submitted: 9 May 2016 9:26 Modified: 1 Jun 2016 11:57
Reporter: Giuseppe Maxia (OCA) Email Updates:
Status: Verified Impact on me:
Category:MySQL Server: Document Store: MySQL Shell Severity:S1 (Critical)
Version:1.0.3 OS:Any
Assigned to: Juan Rene Ramirez Monarrez CPU Architecture:Any

[9 May 2016 9:26] Giuseppe Maxia
When you start mysqlsh in JS mode and try to switch to SQL, you get an error, with an helpful message advising you to connect using the C/S protocol.

Instead, when you start in classic mode and want to switch to JS, there is no failure and no message, but you get errors only when trying to access JS classes:

$ mysqlsh --user=msandbox --sqlc --password=msandbox --port=5712 test
mysqlx: [Warning] Using a password on the command line interface can be insecure.
Creating a Classic Session to msandbox@localhost:5712/test
Default schema `test` accessible through db.

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Currently in SQL mode. Use \js or \py to switch the shell to a scripting language.
mysql-sql> \js
Switching to JavaScript mode...
mysql-js> db.tables
    "t1": <ClassicTable:t1>
mysql-js> t1=db.getTable('t1')
mysql-js> t1.select()
AttributeError: Invalid object member select at (shell):1:2
in t1.select()

How to repeat:
Start the shell in classic mode.
Change to JS mode
Try accessing a database object

Suggested fix:
The shell should either connect to the X-protocol port or refuse to switch to JS/Py.
[10 May 2016 4:09] MySQL Verification Team
Hello Giuseppe,

Thank you for the report.
Verified as described.

[31 May 2016 13:15] Erlend Dahl
Posted by devloper:

This is not a bug, what happens is that you are connecting using a classic
session, the API is very very limited when you do that.
CRUD operations are only available when you use a session through the
XProtocol (XSession or NodeSession)
Here you can see the error is caused because you are trying to use a function
that does not exist on a Classic Table
[31 May 2016 13:28] Giuseppe Maxia
Thanks for your explanation, but I don't think you got my point. 
The issue is that switching to JS from a classic session should generate a meaningful error, while now the user is kept wondering why. 
If a proper connection in JS mode is impossible, the switch command should not work at all.
[2 Jun 2016 4:39] Alfredo Kojima
session.getTable() should indeed just return an error. The way to use JS in a classic session is through session.runSql()