tests: testing out building/installing multiple ext version for pg_cron

nix/ext/pg_cron.nix

@@ -1,32 +1,100 @@
 { lib, stdenv, fetchFromGitHub, postgresql }:
 
-stdenv.mkDerivation rec {
-  pname = "pg_cron";
-  version = "1.6.4";
+let
+  allVersions = {
+    "1.6.4" = {
+      rev = "v1.6.4";
+      hash = "sha256-t1DpFkPiSfdoGG2NgNT7g1lkvSooZoRoUrix6cBID40=";
+    };
+    "1.5.2" = {
+      rev = "v1.5.2";
+      hash = "sha256-+quVWbKJy6wXpL/zwTk5FF7sYwHA7I97WhWmPO/HSZ4=";
+    };
+  };
+
+  mkPgCron = pgCronVersion: { rev, hash }: stdenv.mkDerivation {
+    pname = "pg_cron";
+    version = "${pgCronVersion}-pg${lib.versions.major postgresql.version}";
+
+    buildInputs = [ postgresql ];
 
-  buildInputs = [ postgresql ];
+    src = fetchFromGitHub {
+      owner = "citusdata";
+      repo = "pg_cron";
+      inherit rev hash;
+    };
 
-  src = fetchFromGitHub {
-    owner  = "citusdata";
-    repo   = pname;
-    rev    = "v${version}";
-    hash = "sha256-t1DpFkPiSfdoGG2NgNT7g1lkvSooZoRoUrix6cBID40=";
+    buildPhase = ''
+      make PG_CONFIG=${postgresql}/bin/pg_config
+
+      # Create version-specific SQL file
+      cp pg_cron.sql pg_cron--${pgCronVersion}.sql
+
+      # Create versioned control file with modified module path
+      sed -e "/^default_version =/d" \
+          -e "s|^module_pathname = .*|module_pathname = '\$libdir/pg_cron'|" \
+          pg_cron.control > pg_cron--${pgCronVersion}.control
+    '';
+
+    installPhase = ''
+      mkdir -p $out/{lib,share/postgresql/extension}
+
+      # Install versioned library
+      install -Dm755 pg_cron${postgresql.dlSuffix} $out/lib/pg_cron-${pgCronVersion}${postgresql.dlSuffix}
+
+      # Install version-specific files
+      install -Dm644 pg_cron--${pgCronVersion}.sql $out/share/postgresql/extension/
+      install -Dm644 pg_cron--${pgCronVersion}.control $out/share/postgresql/extension/
+
+      # Install upgrade scripts
+      find . -name 'pg_cron--*--*.sql' -exec install -Dm644 {} $out/share/postgresql/extension/ \;
+    '';
   };
 
+  getVersions = pg:
+    if lib.versionAtLeast pg.version "17"
+    then { "1.6.4" = allVersions."1.6.4"; }
+    else allVersions;
+
+  allVersionsForPg = lib.mapAttrs mkPgCron (getVersions postgresql);
+
+in
+stdenv.mkDerivation {
+  pname = "pg_cron-all";
+  version = "multi";
+
+  buildInputs = lib.attrValues allVersionsForPg;
+
+  dontUnpack = true;
+  dontConfigure = true;
+  dontBuild = true;
+
   installPhase = ''
     mkdir -p $out/{lib,share/postgresql/extension}
-
-    cp *${postgresql.dlSuffix}      $out/lib
-    cp *.sql     $out/share/postgresql/extension
-    cp *.control $out/share/postgresql/extension
+
+    # Install all versions
+    for drv in ${lib.concatStringsSep " " (lib.attrValues allVersionsForPg)}; do
+      ln -sv $drv/lib/* $out/lib/
+      cp -v --no-clobber $drv/share/postgresql/extension/* $out/share/postgresql/extension/ || true
+    done
+
+    # Create default symlinks
+    latest_control=$(ls -v $out/share/postgresql/extension/pg_cron--*.control | tail -n1)
+    latest_version=$(basename "$latest_control" | sed -E 's/pg_cron--([0-9.]+).control/\1/')
+
+    # Create main control file with default_version
+    echo "default_version = '$latest_version'" > $out/share/postgresql/extension/pg_cron.control
+    cat "$latest_control" >> $out/share/postgresql/extension/pg_cron.control
+
+    # Library symlink
+    ln -sfnv pg_cron-$latest_version${postgresql.dlSuffix} $out/lib/pg_cron${postgresql.dlSuffix}
   '';
 
   meta = with lib; {
-    description = "Run Cron jobs through PostgreSQL";
-    homepage    = "https://github.com/citusdata/pg_cron";
-    changelog   = "https://github.com/citusdata/pg_cron/raw/v${version}/CHANGELOG.md";
+    description = "Run Cron jobs through PostgreSQL (multi-version compatible)";
+    homepage = "https://github.com/citusdata/pg_cron";
     maintainers = with maintainers; [ samrose ];
-    platforms   = postgresql.meta.platforms;
-    license     = licenses.postgresql;
+    platforms = postgresql.meta.platforms;
+    license = licenses.postgresql;
   };
 }