MDEV-39223 Reversed executable comments incorrectly written in binlog#4885
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tonychen2001 wants to merge 1 commit intoMariaDB:mainfrom
Open
MDEV-39223 Reversed executable comments incorrectly written in binlog#4885tonychen2001 wants to merge 1 commit intoMariaDB:mainfrom
tonychen2001 wants to merge 1 commit intoMariaDB:mainfrom
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When a reversed executable comment (/*!!version */ or /*M!!version */) is not executed on the master (server version >= specified version), the binlog writer only neutralized the second '!' to a space, leaving `/*! command */`, an executable comment. The slave would then try to execute the comment body as SQL and fail with a parse error. Fix: in the non-executed path, also replace the first '!' with a space so the SQL becomes /* (a plain comment). The restore path for unclosed comments also restores both '!' characters. Added rpl_reversed_comments.test mirroring rpl_conditional_comments.test with reversed equivalents for all forward comment replication test cases: mix of applied/not-applied, prepared statements, unclosed comments, nested comments, delimiter edge case, and MariaDB-specific /*M!! syntax. All new code of the whole pull request, including one or several files that are either new files or modified ones, are contributed under the BSD-new license. I am contributing on behalf of my employer Amazon Web Services, Inc.
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Thank you for fixing this so fast! This is a preliminary review.
LGTM.
Please stand by for the final review.
gkodinov
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Apr 1, 2026
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Description
This addresses an issue introduced in #4724.
When a reversed executable comment (/*!!version */ or /*M!!version */)
is not executed on the master (server version >= specified version),
the binlog writer only neutralized the second '!' to a space, leaving
/*! command */, an executable comment. The slave would then try toexecute the comment body as SQL and fail with a parse error.
Fix: in the non-executed path, also replace the first '!' with a space so the
SQL becomes /* (a plain comment). The restore path for unclosed comments also
restores both '!' characters.
How can this PR be tested?
Added rpl_reversed_comments.test mirroring rpl_conditional_comments.test
with equivalent test cases:
Basing the PR against the correct MariaDB version
Copyright
All new code of the whole pull request, including one or several files that are either new files or modified ones, are contributed under the BSD-new license. I am contributing on behalf of my employer Amazon Web Services, Inc.