feat: include migrations on newer version, for all previous

Author: samrose

nix/ext/pgaudit.nix

@@ -13,19 +13,57 @@ let
   # Load version configuration from external file
   allVersions = (builtins.fromJSON (builtins.readFile ./versions.json)).${pname};
 
-  # Filter versions compatible with current PostgreSQL version
+  # Filter versions compatible with current PostgreSQL version (these get libraries)
   supportedVersions = lib.filterAttrs (
     _: value: builtins.elem (lib.versions.major postgresql.version) value.postgresql
   ) allVersions;
 
   # Derived version information
+  # All versions sorted (for SQL migration files)
+  allVersionsList = lib.naturalSort (lib.attrNames allVersions);
+  # Supported versions sorted (for libraries)
   versions = lib.naturalSort (lib.attrNames supportedVersions);
   latestVersion = lib.last versions;
   numberOfVersions = builtins.length versions;
+
+  # Build packages only for supported versions (with libraries)
   packages = builtins.attrValues (
     lib.mapAttrs (name: value: build name value.hash) supportedVersions
   );
 
+  # Helper function to generate migration SQL file pairs
+  # Returns a list of {from, to} pairs for sequential migrations
+  generateMigrationPairs =
+    versions:
+    let
+      indexed = lib.imap0 (i: v: {
+        idx = i;
+        version = v;
+      }) versions;
+      pairs = lib.filter (x: x.idx > 0) indexed;
+    in
+    map (curr: {
+      from = (lib.elemAt versions (curr.idx - 1));
+      to = curr.version;
+    }) pairs;
+
+  # All migration pairs across all versions (sequential)
+  allMigrationPairs = generateMigrationPairs allVersionsList;
+
+  # Get the first supported version for this PG major
+  firstSupportedVersion = lib.head versions;
+
+  # Generate bridge migrations from unsupported versions to first supported version
+  # These are needed when upgrading PostgreSQL major versions
+  # Only include versions that come BEFORE the first supported version (no backwards migrations)
+  unsupportedVersions = lib.filter (
+    v: !(builtins.elem v versions) && (lib.versionOlder v firstSupportedVersion)
+  ) allVersionsList;
+  bridgeMigrations = map (v: {
+    from = v;
+    to = firstSupportedVersion;
+  }) unsupportedVersions;
+
   # Build function for individual pgaudit versions
   build =
     version: hash:
@@ -64,26 +102,17 @@ let
         # Install shared library with version suffix
         mv ${pname}${postgresql.dlSuffix} $out/lib/${pname}-${version}${postgresql.dlSuffix}
 
-        # Install SQL files
+        # Install SQL files with modifications
         sed -i '1s/^/DROP EVENT TRIGGER IF EXISTS pgaudit_ddl_command_end; \n/' *.sql
         sed -i '1s/^/DROP EVENT TRIGGER IF EXISTS pgaudit_sql_drop; \n/' *.sql
         sed -i 's/CREATE FUNCTION/CREATE OR REPLACE FUNCTION/' *.sql
         cp *.sql $out/share/postgresql/extension
 
-        # Create version-specific control file
+        # Create version-specific control file pointing to versioned library
         sed -e "/^default_version =/d" \
-            -e "s|^module_pathname = .*|module_pathname = '\$libdir/${pname}'|" \
+            -e "s|^module_pathname = .*|module_pathname = '\$libdir/${pname}-${version}'|" \
           ${pname}.control > $out/share/postgresql/extension/${pname}--${version}.control
 
-        # For the latest version, create default control file and symlink
-        if [[ "${version}" == "${latestVersion}" ]]; then
-          {
-            echo "default_version = '${latestVersion}'"
-            cat $out/share/postgresql/extension/${pname}--${latestVersion}.control
-          } > $out/share/postgresql/extension/${pname}.control
-          ln -sfn ${pname}-${latestVersion}${postgresql.dlSuffix} $out/lib/${pname}${postgresql.dlSuffix}
-        fi
-
         runHook postInstall
       '';
 
@@ -104,14 +133,44 @@ buildEnv {
     "/share/postgresql/extension"
   ];
   postBuild = ''
-    # checks
-    (set -x
-       test "$(ls -A $out/lib/${pname}*${postgresql.dlSuffix} | wc -l)" = "${
-         toString (numberOfVersions + 1)
-       }"
-    )
-
-    # Verify all expected library files are present
+    # Create symlinks to latest version for library and control file
+    ln -sfn ${pname}-${latestVersion}${postgresql.dlSuffix} $out/lib/${pname}${postgresql.dlSuffix}
+
+    # Create default control file pointing to latest
+    {
+      echo "default_version = '${latestVersion}'"
+      cat $out/share/postgresql/extension/${pname}--${latestVersion}.control
+    } > $out/share/postgresql/extension/${pname}.control
+
+    # Generate cross-version migration SQL files
+    # For each migration pair, if the target version's base SQL exists but we haven't
+    # built that version (no library), we need to create migration files to bridge from
+    # older versions to the first available version on this PG major
+    ${lib.concatMapStringsSep "\n" (pair: ''
+      # Check if we need to create migration ${pair.from}--${pair.to}.sql
+      if [[ ! -f "$out/share/postgresql/extension/${pname}--${pair.from}--${pair.to}.sql" ]]; then
+        # If the target SQL file exists, create the migration by copying it
+        if [[ -f "$out/share/postgresql/extension/${pname}--${pair.to}.sql" ]]; then
+          cp "$out/share/postgresql/extension/${pname}--${pair.to}.sql" \
+             "$out/share/postgresql/extension/${pname}--${pair.from}--${pair.to}.sql"
+        fi
+      fi
+    '') allMigrationPairs}
+
+    # Generate bridge migrations from unsupported versions to first supported version
+    # This handles cross-PostgreSQL-major-version upgrades
+    ${lib.concatMapStringsSep "\n" (pair: ''
+      # Create bridge migration ${pair.from}--${pair.to}.sql if not already present
+      if [[ ! -f "$out/share/postgresql/extension/${pname}--${pair.from}--${pair.to}.sql" ]]; then
+        # The bridge migration is just a copy of the target version's base SQL
+        if [[ -f "$out/share/postgresql/extension/${pname}--${pair.to}.sql" ]]; then
+          cp "$out/share/postgresql/extension/${pname}--${pair.to}.sql" \
+             "$out/share/postgresql/extension/${pname}--${pair.from}--${pair.to}.sql"
+        fi
+      fi
+    '') bridgeMigrations}
+
+    # Verify all expected library files are present (one per version + symlink)
     expectedFiles=${toString (numberOfVersions + 1)}
     actualFiles=$(ls -A $out/lib/${pname}*${postgresql.dlSuffix} | wc -l)