Re: pgsql: Add support event triggers on authenticated login

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> writes:
> Hi, I'm seeing a compiler warning with CFLAGS -O3 but not with -O2.

> In file included from dbcommands.c:20:
> dbcommands.c: In function ‘createdb’:
> ../../../src/include/postgres.h:104:16: warning: ‘src_hasloginevt’ may
> be used uninitialized in this function [-Wmaybe-uninitialized]

Hmm, I also see that at -O3 (not at -O2) when using Fedora 39's
gcc 13.2.1, but *not* when using RHEL8's gcc 8.5.0.

I'm not sure how excited I am about curing that, though, because gcc
13.2.1 spews several other totally baseless warnings (see attached).
Some of them match up with warnings we're seeing on buildfarm member
serinus, which I seem to recall that Andres had tracked to a known gcc
bug.

            regards, tom lane

In file included from dbcommands.c:20:
In function 'BoolGetDatum',
    inlined from 'createdb' at dbcommands.c:1379:52:
../../../src/include/postgres.h:104:16: warning: 'src_hasloginevt' may be used uninitialized [-Wmaybe-uninitialized]
  104 |         return (Datum) (X ? 1 : 0);
      |                ^~~~~~~~~~~~~~~~~~~
dbcommands.c: In function 'createdb':
dbcommands.c:683:25: note: 'src_hasloginevt' was declared here
  683 |         bool            src_hasloginevt;
      |                         ^~~~~~~~~~~~~~~
In file included from ../../../../src/include/executor/instrument.h:16,
                 from pgstat_io.c:19:
pgstat_io.c: In function 'pgstat_count_io_op_time':
pgstat_io.c:149:60: warning: array subscript 2 is above array bounds of 'instr_time[2][4][8]' [-Warray-bounds=]
  149 |                 INSTR_TIME_ADD(PendingIOStats.pending_times[io_object][io_context][io_op],
      |                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
../../../../src/include/portability/instr_time.h:179:11: note: in definition of macro 'INSTR_TIME_ADD'
  179 |         ((x).ticks += (y).ticks)
      |           ^
pgstat_io.c:27:25: note: while referencing 'pending_times'
   27 |         instr_time      pending_times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
      |                         ^~~~~~~~~~~~~
pgstat_io.c:149:60: warning: array subscript 2 is above array bounds of 'instr_time[2][4][8]' [-Warray-bounds=]
  149 |                 INSTR_TIME_ADD(PendingIOStats.pending_times[io_object][io_context][io_op],
      |                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
../../../../src/include/portability/instr_time.h:179:11: note: in definition of macro 'INSTR_TIME_ADD'
  179 |         ((x).ticks += (y).ticks)
      |           ^
pgstat_io.c:27:25: note: while referencing 'pending_times'
   27 |         instr_time      pending_times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
      |                         ^~~~~~~~~~~~~
pgstat_io.c:149:60: warning: array subscript 2 is above array bounds of 'instr_time[2][4][8]' [-Warray-bounds=]
  149 |                 INSTR_TIME_ADD(PendingIOStats.pending_times[io_object][io_context][io_op],
      |                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
../../../../src/include/portability/instr_time.h:179:11: note: in definition of macro 'INSTR_TIME_ADD'
  179 |         ((x).ticks += (y).ticks)
      |           ^
pgstat_io.c:27:25: note: while referencing 'pending_times'
   27 |         instr_time      pending_times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
      |                         ^~~~~~~~~~~~~
pgstat_io.c:149:60: warning: array subscript 2 is above array bounds of 'instr_time[2][4][8]' [-Warray-bounds=]
  149 |                 INSTR_TIME_ADD(PendingIOStats.pending_times[io_object][io_context][io_op],
      |                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
../../../../src/include/portability/instr_time.h:179:11: note: in definition of macro 'INSTR_TIME_ADD'
  179 |         ((x).ticks += (y).ticks)
      |           ^
pgstat_io.c:27:25: note: while referencing 'pending_times'
   27 |         instr_time      pending_times[IOOBJECT_NUM_TYPES][IOCONTEXT_NUM_TYPES][IOOP_NUM_TYPES];
      |                         ^~~~~~~~~~~~~
In file included from ../../../../src/include/access/htup_details.h:22,
                 from pl_exec.c:21:
In function 'assign_simple_var',
    inlined from 'exec_set_found' at pl_exec.c:8349:2:
../../../../src/include/varatt.h:230:36: warning: array subscript 0 is outside array bounds of 'char[0]'
[-Warray-bounds=]
  230 |         (((varattrib_1b_e *) (PTR))->va_tag)
      |                                    ^
../../../../src/include/varatt.h:94:12: note: in definition of macro 'VARTAG_IS_EXPANDED'
   94 |         (((tag) & ~1) == VARTAG_EXPANDED_RO)
      |            ^~~
../../../../src/include/varatt.h:284:57: note: in expansion of macro 'VARTAG_1B_E'
  284 | #define VARTAG_EXTERNAL(PTR)                            VARTAG_1B_E(PTR)
      |                                                         ^~~~~~~~~~~
../../../../src/include/varatt.h:301:57: note: in expansion of macro 'VARTAG_EXTERNAL'
  301 |         (VARATT_IS_EXTERNAL(PTR) && !VARTAG_IS_EXPANDED(VARTAG_EXTERNAL(PTR)))
      |                                                         ^~~~~~~~~~~~~~~
pl_exec.c:8537:17: note: in expansion of macro 'VARATT_IS_EXTERNAL_NON_EXPANDED'
 8537 |                 VARATT_IS_EXTERNAL_NON_EXPANDED(DatumGetPointer(newvalue)))
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'exec_set_found':
cc1: note: source object is likely at address zero