Memory leak in pg_query_parse.c:52

[kky0h]

Hi, I compiled the 'parse_plpgsql.c' and tested it with file "plpgsql_samples.sql". ASan and valgrind find memory leak in pg_query_parse.c:52

==136926==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 1 byte(s) in 1 object(s) allocated from:
    #0 0x7fd98c8b32f0 in __strdup (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x752f0)
    #1 0x414020 in pg_query_raw_parse src/pg_query_parse.c:52

SUMMARY: AddressSanitizer: 1 byte(s) leaked in 1 allocation(s).

==137686== Memcheck, a memory error detector
==137686== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==137686== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==137686== Command: ./parse_plpgsql plpgsql_samples.sql
==137686== 
==137686== 
==137686== HEAP SUMMARY:
==137686==     in use at exit: 345,690 bytes in 45 blocks
==137686==   total heap usage: 198 allocs, 153 frees, 1,276,459 bytes allocated
==137686== 
==137686== 1 bytes in 1 blocks are definitely lost in loss record 1 of 31
==137686==    at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==137686==    by 0x4EBFB49: strdup (strdup.c:42)
==137686==    by 0x414020: pg_query_raw_parse (pg_query_parse.c:52)
==137686==    by 0x4022BC: pg_query_parse_plpgsql (pg_query_parse_plpgsql.c:396)
==137686==    by 0x401785: main (parse_plpgsql.c:44)
==137686== 
==137686== LEAK SUMMARY:
==137686==    definitely lost: 1 bytes in 1 blocks
==137686==    indirectly lost: 0 bytes in 0 blocks
==137686==      possibly lost: 0 bytes in 0 blocks
==137686==    still reachable: 345,689 bytes in 44 blocks
==137686==         suppressed: 0 bytes in 0 blocks
==137686== Reachable blocks (those to which a pointer was found) are not shown.
==137686== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==137686== 
==137686== For counts of detected and suppressed errors, rerun with: -v
==137686== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 1)

After debugging by gdb, I found it seems 'result.stderr_buffer' doesn't free correctly when parse plpgsql.(seems function pg_query_free_parse_result(pg_query_parse.c:116) doesn't be called.)

[lfittl]

Thanks for the report!

Would you be available to make a pull request that fixes this issue?