Memory leaks when using delta_scan

[kdang-at-safe]

We encountered some memory leaks when DuckDB is built with the address sanitizer. The problem occurs when reading from a delta table using delta_scan().

Repro

• Build DuckDB and Delta Extension with address sanitizer.
• In DuckDB console, run select * from delta_scan('/path/to/some-table');
• Exit console, and memory leaks are dumped.

I've attached the table I used, and the asan logs that were dumped for me:

some-table.zip
sanitize asan leaks.txt

Notes

I am unsure whether this problem is from the Delta extension, or the Delta Kernel. But this is what I found while looking into it a bit.

• The problem appears to occur in DeltaMultiFileList::GetFileInternal() after ffi::scan_metadata_next() was called.
• I tried the ffi/examples/read-table example in delta-kernel-rs which used the same call, and it did not have any memory leaks reported.
• The attached log of memory leaks were from one run of delta_scan(). Each subsequent call to delta_scan() increases the leak size.