Merge: postgresql.pg_config: add check to confirm output is correct (#392418)

doc/release-notes/rl-2505.section.md

@@ -11,7 +11,7 @@
 - `squid` has been updated to version 7, this release includes multiple breaking changes, like ESI removal.
   For more information, [check the release notes](https://github.com/squid-cache/squid/releases/tag/SQUID_7_0_1).
 
-- `postgresql` and `libpq` don't provide `pg_config` by default anymore. Instead, `pg_config` is available via `postgresql.pg_config` or `libpq.pg_config`. This allowed implementing it as a shell script, which can be build for both the build and host systems when cross-compiling. If your build fails to find `pg_config`, add `postgresql.pg_config` or `libpq.pg_config` to `nativeBuildInputs`.
+- `postgresql` and `libpq` don't provide `pg_config` by default anymore. Instead, `pg_config` is available via `postgresql.pg_config` or `libpq.pg_config`. This allowed implementing it as a shell script, which can be built for both the build and host systems when cross-compiling. If your build fails to find `pg_config`, add `postgresql.pg_config` or `libpq.pg_config` to `nativeBuildInputs`.
 
 - The [`no-broken-symlinks` hook](https://nixos.org/manual/nixpkgs/unstable/#no-broken-symlinks.sh) was added to catch builds containing dangling or reflexive symlinks, as these are indicative of problems with packaging.
   The hook can be disabled by providing `dontCheckForBrokenSymlinks = true;` as an argument to `mkDerivation`.

pkgs/servers/sql/postgresql/generic.nix

@@ -366,6 +366,7 @@ let
 
       postPatch = ''
         substituteInPlace "src/Makefile.global.in" --subst-var out
+        substituteInPlace "src/common/config_info.c" --subst-var dev
         cat ${./pg_config.env.mk} >> src/common/Makefile
       '';
 
@@ -373,7 +374,12 @@ let
         ''
           moveToOutput "bin/ecpg" "$dev"
           moveToOutput "lib/pgxs" "$dev"
-
+        ''
+        + lib.optionalString (stdenv'.buildPlatform.canExecute stdenv'.hostPlatform) ''
+          mkdir -p "$dev/nix-support"
+          "$out/bin/pg_config" > "$dev/nix-support/pg_config.expected"
+        ''
+        + ''
           rm "$out/bin/pg_config"
           make -C src/common pg_config.env
           install -D src/common/pg_config.env "$dev/nix-support/pg_config.env"

pkgs/servers/sql/postgresql/pg_config.nix

@@ -1,7 +1,9 @@
 {
+  diffutils,
   lib,
   replaceVarsWith,
   runtimeShell,
+  stdenv,
   # PostgreSQL package
   finalPackage,
 }:
@@ -15,4 +17,12 @@ replaceVarsWith {
     inherit runtimeShell;
     postgresql-dev = lib.getDev finalPackage;
   };
+  nativeCheckInputs = [
+    diffutils
+  ];
+  postCheck = ''
+    if [ -e ${lib.getDev finalPackage}/nix-support/pg_config.expected ]; then
+        diff ${lib.getDev finalPackage}/nix-support/pg_config.expected <($out/bin/pg_config)
+    fi
+  '';
 }