Fix expression lifetime problems

[bradfordboyle]

No description provided.

[bradfordboyle]

@df7cb Here are the extension and packaging changes for PostgreSQL 18. A couple of notes:

• It looks like the changes for PostgreSQL 17 were only pushed to the repo on git.postgresql.org and not to either GitHub or Codeberg so they are showing up as the first commit in this PR.
• I've split the changes into two separate commits: 1) a commit updates the extension code to address compilation against PostgreSQL 18, and 2) a commit that updates the Debian packaging for. It's easy enough to squash these commits if needed.
• Because the extension source was changing, building the package failed locally unless I changed the extension version from 1.3.1 to 1.3.2. I saw the conversation on Discord about using semantic versioning for extensions. If you'd prefer, I can change the version to 1.4.

[df7cb]

We should move the Debian part to salsa. The different upstream and Debian release/package update cycles just don't work together. I created a new repo there: https://salsa.debian.org/postgresql/pgfincore. But before that, we should clean up the mess here.

@klando what's the future of pgfincore? Is it still useful? There are a few WIP branches by you from 2023/2024, could you merge the good ones and make a new version?

[df7cb]

I pushed the actual patch part as 31f9ae9.

clang is reporting some expression lifetime problems:

make[1]: Verzeichnis „/home/myon/projects/postgresql/pgfincore/pgfincore/build-18“ wird betreten
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type -Wshadow=compatible-local -Wformat-security -Wmissing-variable-declarations -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation -g -g -O2 -Werror=implicit-function-declaration -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -fno-omit-frame-pointer -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/home/myon/projects/postgresql/pgfincore/pgfincore=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -fPIC -fvisibility=hidden -I. -I/home/myon/postgresql/pgfincore/pgfincore -I/usr/include/postgresql/18/server -I/usr/include/postgresql/internal -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE  -I/usr/include/libxml2     -c -o pgfincore.o /home/myon/postgresql/pgfincore/pgfincore/pgfincore.c
/usr/bin/clang-21 -Wno-ignored-attributes -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wno-unused-command-line-argument -Wno-compound-token-split-by-macro -Wno-format-truncation -O2  -I. -I/home/myon/postgresql/pgfincore/pgfincore -I/usr/include/postgresql/18/server -I/usr/include/postgresql/internal -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE  -I/usr/include/libxml2    -flto=thin -emit-llvm -c -o pgfincore.bc /home/myon/postgresql/pgfincore/pgfincore/pgfincore.c
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:366:24: warning: object backing the pointer 'fctx->relationpath' will be destroyed
      at the end of the full-expression [-Wdangling-assignment]
  366 |                 fctx->relationpath = relpathpg(fctx->rel, forkName);
      |                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:154:9: note: expanded from macro 'relpathpg'
  154 |         relpathbackend((rel)->rd_locator, (rel)->rd_backend, (forkname_to_number(text_to_cstring(forkName)))).str
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/postgresql/18/server/common/relpath.h:143:2: note: expanded from macro 'relpathbackend'
  143 |         GetRelationPath((rlocator).dbOid, (rlocator).spcOid, (rlocator).relNumber, \
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  144 |                                         backend, forknum)
      |                                         ~~~~~~~~~~~~~~~~~
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:640:17: warning: object backing the pointer 'relationpath' will be destroyed at
      the end of the full-expression [-Wdangling-assignment]
  640 |         relationpath = relpathpg(rel, forkName);
      |                        ^~~~~~~~~~~~~~~~~~~~~~~~
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:154:9: note: expanded from macro 'relpathpg'
  154 |         relpathbackend((rel)->rd_locator, (rel)->rd_backend, (forkname_to_number(text_to_cstring(forkName)))).str
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/postgresql/18/server/common/relpath.h:143:2: note: expanded from macro 'relpathbackend'
  143 |         GetRelationPath((rlocator).dbOid, (rlocator).spcOid, (rlocator).relNumber, \
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  144 |                                         backend, forknum)
      |                                         ~~~~~~~~~~~~~~~~~
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:949:24: warning: object backing the pointer 'fctx->relationpath' will be destroyed
      at the end of the full-expression [-Wdangling-assignment]
  949 |                 fctx->relationpath = relpathpg(fctx->rel, forkName);
      |                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/myon/postgresql/pgfincore/pgfincore/pgfincore.c:154:9: note: expanded from macro 'relpathpg'
  154 |         relpathbackend((rel)->rd_locator, (rel)->rd_backend, (forkname_to_number(text_to_cstring(forkName)))).str
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/postgresql/18/server/common/relpath.h:143:2: note: expanded from macro 'relpathbackend'
  143 |         GetRelationPath((rlocator).dbOid, (rlocator).spcOid, (rlocator).relNumber, \
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  144 |                                         backend, forknum)
      |                                         ~~~~~~~~~~~~~~~~~
3 warnings generated.

I'm uploading a new Debian package with this to get the package unstuck there, but I think this should be resolved before a new version is pushed out with this. (Ok, admittedly this also avoiding the "do we update the extension version" question 😅 )

[c2main]

We should move the Debian part to salsa. The different upstream and Debian release/package update cycles just don't work together. I created a new repo there: https://salsa.debian.org/postgresql/pgfincore. But before that, we should clean up the mess here.

@klando what's the future of pgfincore? Is it still useful? There are a few WIP branches by you from 2023/2024, could you merge the good ones and make a new version?

Value may have decreased over time but it looks like it's still the only tool providing the features it brings.
I was trying to get to a new version with added linux syscalls...