Simplify V77/V78 migrations — remove over-engineered column detection

V77: replace information_schema role_uuid detection + duplicated
PL/pgSQL loops with a simple DELETE+UPDATE using role_id (always
present as the original column).

V78: remove separate column_exists? check — ensure_uuid_column is
fully idempotent (ADD COLUMN IF NOT EXISTS, WHERE uuid IS NULL),
so pre-checking is unnecessary.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ddon

lib/phoenix_kit/migrations/postgres/v77.ex

@@ -57,47 +57,21 @@ defmodule PhoenixKit.Migrations.Postgres.V77 do
 
   # Renames role permission module_key. If target already exists for the same role,
   # deletes the source row to avoid unique constraint violations.
-  # Dynamically detects whether uuid/role_uuid columns exist (V56 may have skipped them)
-  # and falls back to id/role_id when they don't.
-  defp rename_role_permission(table, from_key, to_key, prefix) do
-    schema = prefix || "public"
-
+  # Uses role_id (always present, original column) for duplicate detection.
+  defp rename_role_permission(table, from_key, to_key, _prefix) do
     execute("""
     DO $$
-    DECLARE
-      has_role_uuid BOOLEAN;
-      r RECORD;
     BEGIN
-      SELECT EXISTS (
-        SELECT 1 FROM information_schema.columns
-        WHERE table_schema = '#{schema}'
-        AND table_name = 'phoenix_kit_role_permissions'
-        AND column_name = 'role_uuid'
-      ) INTO has_role_uuid;
-
-      IF has_role_uuid THEN
-        FOR r IN SELECT uuid, role_uuid FROM #{table} WHERE module_key = '#{from_key}' LOOP
-          IF EXISTS (
-            SELECT 1 FROM #{table}
-            WHERE module_key = '#{to_key}' AND role_uuid = r.role_uuid
-          ) THEN
-            DELETE FROM #{table} WHERE uuid = r.uuid;
-          ELSE
-            UPDATE #{table} SET module_key = '#{to_key}' WHERE uuid = r.uuid;
-          END IF;
-        END LOOP;
-      ELSE
-        FOR r IN SELECT id, role_id FROM #{table} WHERE module_key = '#{from_key}' LOOP
-          IF EXISTS (
-            SELECT 1 FROM #{table}
-            WHERE module_key = '#{to_key}' AND role_id = r.role_id
-          ) THEN
-            DELETE FROM #{table} WHERE id = r.id;
-          ELSE
-            UPDATE #{table} SET module_key = '#{to_key}' WHERE id = r.id;
-          END IF;
-        END LOOP;
-      END IF;
+      -- Delete source rows where target already exists for the same role
+      DELETE FROM #{table} src
+      WHERE src.module_key = '#{from_key}'
+        AND EXISTS (
+          SELECT 1 FROM #{table} tgt
+          WHERE tgt.module_key = '#{to_key}' AND tgt.role_id = src.role_id
+        );
+
+      -- Rename remaining rows
+      UPDATE #{table} SET module_key = '#{to_key}' WHERE module_key = '#{from_key}';
     END $$;
     """)
   end

lib/phoenix_kit/migrations/postgres/v78.ex

@@ -37,11 +37,9 @@ defmodule PhoenixKit.Migrations.Postgres.V78 do
                            )
 
       if table_exists?(:phoenix_kit_ai_prompts, prefix) do
-        # V56 may have skipped adding the uuid column to ai_prompts if the table
-        # didn't exist at V56 time. Ensure it exists before creating the FK.
-        unless column_exists?(:phoenix_kit_ai_prompts, :uuid, prefix) do
-          ensure_uuid_column_and_index(:phoenix_kit_ai_prompts, prefix)
-        end
+        # V56 skips tables that don't exist yet, so ai_prompts may lack a uuid
+        # column if the AI module was enabled after V56 ran. Ensure it exists.
+        ensure_uuid_column(:phoenix_kit_ai_prompts, prefix)
 
         execute """
         DO $$
@@ -119,45 +117,23 @@ defmodule PhoenixKit.Migrations.Postgres.V78 do
     exists
   end
 
-  defp column_exists?(table_name, column_name, prefix) do
-    query = """
-    SELECT EXISTS (
-      SELECT FROM information_schema.columns
-      WHERE table_schema = '#{prefix}'
-      AND table_name = '#{table_name}'
-      AND column_name = '#{column_name}'
-    )
-    """
-
-    %{rows: [[exists]]} = PhoenixKit.RepoHelper.repo().query!(query)
-    exists
-  end
-
-  # Replicates V56's idempotent pattern for adding a uuid column with
-  # backfill, NOT NULL constraint, and unique index.
-  defp ensure_uuid_column_and_index(table_name, prefix) do
+  # Idempotently adds uuid column + backfill + NOT NULL + unique index.
+  # All statements use IF NOT EXISTS / IF NULL guards, safe to run on tables
+  # that already have the column.
+  defp ensure_uuid_column(table_name, prefix) do
     full_table = "#{prefix_str(prefix)}#{table_name}"
-    index_name = "#{table_name}_uuid_index"
 
     execute("""
     ALTER TABLE #{full_table}
     ADD COLUMN IF NOT EXISTS uuid UUID DEFAULT uuid_generate_v7()
     """)
 
-    execute("""
-    UPDATE #{full_table}
-    SET uuid = uuid_generate_v7()
-    WHERE uuid IS NULL
-    """)
+    execute("UPDATE #{full_table} SET uuid = uuid_generate_v7() WHERE uuid IS NULL")
 
-    execute("""
-    ALTER TABLE #{full_table}
-    ALTER COLUMN uuid SET NOT NULL
-    """)
+    execute("ALTER TABLE #{full_table} ALTER COLUMN uuid SET NOT NULL")
 
     execute("""
-    CREATE UNIQUE INDEX IF NOT EXISTS #{index_name}
-    ON #{full_table}(uuid)
+    CREATE UNIQUE INDEX IF NOT EXISTS #{table_name}_uuid_index ON #{full_table}(uuid)
     """)
   end