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Date: Wed, 07 Jun 2023 09:31:10 -0500
Subject: Fix last unitialized memory warning
To: <pgsql-hackers@postgresql.org>
From: "Tristan Partin" <tristan@neon.tech>
Message-Id: <CT6HJ3U8068R.3A8SJMV02D9BC@gonk>
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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 =E2=80=98assign_simple_var=E2=80=99,
    inlined from =E2=80=98exec_set_found=E2=80=99 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 =E2=80=98char[0]=E2=80=99 [-Warray-bounds=3D]
  230 |         (((varattrib_1b_e *) (PTR))->va_tag)
      |                                    ^
../src/include/varatt.h:94:12: note: in definition of macro =E2=80=98VARTAG=
_IS_EXPANDED=E2=80=99
   94 |         (((tag) & ~1) =3D=3D VARTAG_EXPANDED_RO)
      |            ^~~
../src/include/varatt.h:284:57: note: in expansion of macro =E2=80=98VARTAG=
_1B_E=E2=80=99
  284 | #define VARTAG_EXTERNAL(PTR)                            VARTAG_1B_E=
(PTR)
      |                                                         ^~~~~~~~~~~
../src/include/varatt.h:301:57: note: in expansion of macro =E2=80=98VARTAG=
_EXTERNAL=E2=80=99
  301 |         (VARATT_IS_EXTERNAL(PTR) && !VARTAG_IS_EXPANDED(VARTAG_EXTE=
RNAL(PTR)))
      |                                                         ^~~~~~~~~~~=
~~~~
../src/pl/plpgsql/src/pl_exec.c:8537:17: note: in expansion of macro =E2=80=
=98VARATT_IS_EXTERNAL_NON_EXPANDED=E2=80=99
 8537 |                 VARATT_IS_EXTERNAL_NON_EXPANDED(DatumGetPointer(new=
value)))
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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.

--=20
Tristan Partin
Neon (https://neon.tech)

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