Re: Fix last unitialized memory warning

On 07.06.23 16:31, Tristan Partin wrote:
> This patch is really not necessary from a functional point of view. It
> is only necessary if we want to silence a compiler warning.
>
> Tested on `gcc (GCC) 13.1.1 20230511 (Red Hat 13.1.1-2)`.
>
> After silencing this warning, all I am left with (given my build
> configuration) is:
>
> [1667/2280] Compiling C object src/pl/plpgsql/src/plpgsql.so.p/pl_exec.c.o
> In file included from ../src/include/access/htup_details.h:22,
> from ../src/pl/plpgsql/src/pl_exec.c:21:
> In function ‘assign_simple_var’,
> inlined from ‘exec_set_found’ at ../src/pl/plpgsql/src/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)))
> | ^~~~~~~~~~~~~~~
> ../src/pl/plpgsql/src/pl_exec.c:8537:17: note: in expansion of macro ‘VARATT_IS_EXTERNAL_NON_EXPANDED’
> 8537 | VARATT_IS_EXTERNAL_NON_EXPANDED(DatumGetPointer(newvalue)))
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> From my perspective, this warning definitely seems like a false
> positive, but I don't know the code well-enough to say that for certain.

I cannot reproduce this warning with gcc-13. Are you using any
non-standard optimization options. Could you give your full configure
and build commands and the OS?