postgresql.withPackages.pg_config: fix paths

Previously, pg_config would report the paths of the underlying
postgresql derivation and not the paths of the buildEnv that
postgresql.withPackages creates.

That's a problem when users of pg_config use it to find PostgreSQL's
sharedir, in which they'd like to find the extensions added via
withPackages. Those are only linked into the created buildEnv, but not
available in the postgresql derivation.

By providing our own nix-support/pg_config.env file, we can swap out
those paths. We also do the same for the -man output, because this
output is linked into buildEnv as well. Other paths, which are not
available in the buildEnv environment, will still link to the original
postgresql derivation. Win-win!

pkgs/servers/sql/postgresql/ext/omnigres.nix

@@ -12,6 +12,7 @@
   postgresqlBuildExtension,
   postgresqlTestExtension,
   python3,
+  stdenv,
   unstableGitUpdater,
 }:
 
@@ -29,6 +30,16 @@ postgresqlBuildExtension (finalAttrs: {
     hash = "sha256-LKsH+aeLg7v2RfK80D3mgXdPB8jMIv5uFdf+3c5Z0vA=";
   };
 
+  # This matches postInstall of PostgreSQL's generic.nix, which does this for the PGXS Makefile.
+  # Since omnigres uses a CMake file, which tries to replicate the things that PGXS does, we need
+  # to apply the same fix for darwin.
+  # The reason we need to do this is, because PG_BINARY will point at the postgres wrapper of
+  # postgresql.withPackages, which does not contain the same symbols as the original file, ofc.
+  postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    substituteInPlace "cmake/PostgreSQLExtension.cmake" \
+      --replace-fail '-bundle_loader ''${PG_BINARY}' "-bundle_loader ${postgresql}/bin/postgres"
+  '';
+
   strictDeps = true;
 
   nativeBuildInputs = [
@@ -48,8 +59,6 @@ postgresqlBuildExtension (finalAttrs: {
   cmakeFlags = [
     "-DOPENSSL_CONFIGURED=1"
     "-DPG_CONFIG=${pgWithExtensions.pg_config}/bin/pg_config"
-    "-DPostgreSQL_EXTENSION_DIR=${pgWithExtensions}/share/postgresql/extension/"
-    "-DPostgreSQL_PACKAGE_LIBRARY_DIR=${pgWithExtensions}/lib/"
     "-DPostgreSQL_TARGET_EXTENSION_DIR=${builtins.placeholder "out"}/share/postgresql/extension/"
     "-DPostgreSQL_TARGET_PACKAGE_LIBRARY_DIR=${builtins.placeholder "out"}/lib/"
   ];

pkgs/servers/sql/postgresql/generic.nix

@@ -610,66 +610,78 @@ let
     f:
     let
       installedExtensions = f postgresql.pkgs;
-    in
-    buildEnv {
-      name = "${postgresql.pname}-and-plugins-${postgresql.version}";
-      paths = installedExtensions ++ [
-        postgresql
-        postgresql.man # in case user installs this into environment
-      ];
+      finalPackage = buildEnv {
+        name = "${postgresql.pname}-and-plugins-${postgresql.version}";
+        paths = installedExtensions ++ [
+          # consider keeping in-sync with `postBuild` below
+          postgresql
+          postgresql.man # in case user installs this into environment
+        ];
 
-      pathsToLink = [
-        "/"
-        "/bin"
-      ];
+        pathsToLink = [
+          "/"
+          "/bin"
+          "/share/postgresql/extension"
+          # Unbreaks Omnigres' build system
+          "/share/postgresql/timezonesets"
+          "/share/postgresql/tsearch_data"
+        ];
 
-      nativeBuildInputs = [ makeBinaryWrapper ];
-      postBuild =
-        let
-          args = lib.concatMap (ext: ext.wrapperArgs or [ ]) installedExtensions;
-        in
-        ''
-          wrapProgram "$out/bin/postgres" ${lib.concatStringsSep " " args}
-        '';
+        nativeBuildInputs = [ makeBinaryWrapper ];
+        postBuild =
+          let
+            args = lib.concatMap (ext: ext.wrapperArgs or [ ]) installedExtensions;
+          in
+          ''
+            wrapProgram "$out/bin/postgres" ${lib.concatStringsSep " " args}
 
-      passthru = {
-        inherit installedExtensions;
-        inherit (postgresql)
-          pg_config
-          pkgs
-          psqlSchema
-          version
-          ;
+            mkdir -p "$out/nix-support"
+            substitute "${lib.getDev postgresql}/nix-support/pg_config.env" "$out/nix-support/pg_config.env" \
+              --replace-fail "${postgresql}" "$out" \
+              --replace-fail "${postgresql.man}" "$out"
+          '';
 
-        withJIT = postgresqlWithPackages {
-          inherit
-            buildEnv
-            lib
-            makeBinaryWrapper
-            postgresql
+        passthru = {
+          inherit installedExtensions;
+          inherit (postgresql)
+            pkgs
+            psqlSchema
+            version
             ;
-        } (_: installedExtensions ++ [ postgresql.jit ]);
-        withoutJIT = postgresqlWithPackages {
-          inherit
-            buildEnv
-            lib
-            makeBinaryWrapper
-            postgresql
-            ;
-        } (_: lib.remove postgresql.jit installedExtensions);
 
-        withPackages =
-          f':
-          postgresqlWithPackages {
+          pg_config = postgresql.pg_config.override { inherit finalPackage; };
+
+          withJIT = postgresqlWithPackages {
             inherit
               buildEnv
               lib
               makeBinaryWrapper
               postgresql
               ;
-          } (ps: installedExtensions ++ f' ps);
+          } (_: installedExtensions ++ [ postgresql.jit ]);
+          withoutJIT = postgresqlWithPackages {
+            inherit
+              buildEnv
+              lib
+              makeBinaryWrapper
+              postgresql
+              ;
+          } (_: lib.remove postgresql.jit installedExtensions);
+
+          withPackages =
+            f':
+            postgresqlWithPackages {
+              inherit
+                buildEnv
+                lib
+                makeBinaryWrapper
+                postgresql
+                ;
+            } (ps: installedExtensions ++ f' ps);
+        };
       };
-    };
+    in
+    finalPackage;
 
 in
 # passed by <major>.nix

pkgs/servers/sql/postgresql/pg_config.env.mk

@@ -9,5 +9,6 @@ pg_config.env: $(top_builddir)/src/port/pg_config_paths.h | $(top_builddir)/src/
 	echo "LDFLAGS_EX=\"$(LDFLAGS_EX)\"" >>$@
 	echo "LDFLAGS_SL=\"$(LDFLAGS_SL)\"" >>$@
 	echo "LIBS=\"$(LIBS)\"" >>$@
+	echo "PGXS=\"$(dev)/lib/pgxs/src/makefiles/pgxs.mk\"" >>$@
 	cat $(top_builddir)/src/port/pg_config_paths.h $(top_builddir)/src/include/pg_config.h \
 	  | sed -nE 's/^#define ([^ ]+) ("?)(.*)\2$$/\1="\3"/p' >>$@

pkgs/servers/sql/postgresql/pg_config.sh

@@ -70,7 +70,7 @@ for opt; do
         --mandir)               show+=("$MANDIR") ;;
         --sharedir)             show+=("$PGSHAREDIR") ;;
         --sysconfdir)           show+=("$SYSCONFDIR") ;;
-        --pgxs)                 show+=("@postgresql-dev@/lib/pgxs/src/makefiles/pgxs.mk") ;;
+        --pgxs)                 show+=("$PGXS") ;;
         --configure)            show+=("$CONFIGURE_ARGS") ;;
         --cc)                   show+=("$CC") ;;
         --cppflags)             show+=("$CPPFLAGS") ;;
@@ -108,7 +108,7 @@ LOCALEDIR = $LOCALEDIR
 MANDIR = $MANDIR
 SHAREDIR = $PGSHAREDIR
 SYSCONFDIR = $SYSCONFDIR
-PGXS = @postgresql-dev@/lib/pgxs/src/makefiles/pgxs.mk
+PGXS = $PGXS
 CONFIGURE = $CONFIGURE_ARGS
 CC = $CC
 CPPFLAGS = $CPPFLAGS