Cherry pick #104751 to 26.4: Fix use-after-free in AvroConfluentRowInputFormat#104847
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robot-clickhouse-ci-1 merged 6 commits intoMay 13, 2026
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`AvroConfluentRowInputFormat::getOrCreateDeserializer` built an `AvroDeserializer` on the stack and copied it into `deserializer_cache`. The deserializer holds `symbolic_skip_fn_map`, and skip lambdas in its action tree capture references into that map. Copying deep-copies the map to a new address while the lambdas still reference the original; once the stack local is destroyed those references dangle, and the next row deserialization invokes a `std::function` over freed memory. Move into the cache instead of copying. `std::map` move-construction transfers existing nodes without relocating them, so the captured references remain valid.
Prevent reintroduction of the use-after-free fixed in the previous commit. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The previous schema's symbolic reference sat at the top level of a skipped field, so createAction resolved it before createSkipFn was called, never building the reference-capturing lambda. A recursive Node schema with `next: ["null", "Node"]` puts the symbolic node inside a union branch, which is one of the spots createSkipFn recurses into on its own. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…lizer-copy Fix use-after-free in `AvroConfluentRowInputFormat`
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Original pull-request #104751
Do not merge this PR manually
This pull-request is a first step of an automated backporting.
It contains changes similar to calling
git cherry-picklocally.If you intend to continue backporting the changes, then resolve all conflicts if any.
Otherwise, if you do not want to backport them, then just close this pull-request.
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