fix: drop trigger/function order

internal/diff/diff.go

@@ -963,6 +963,9 @@ func (d *ddlDiff) generateModifySQL(targetSchema string, collector *diffCollecto
 // generateDropSQL generates DROP statements in reverse dependency order
 func (d *ddlDiff) generateDropSQL(targetSchema string, collector *diffCollector) {
 
+	// Drop triggers from modified tables first (triggers depend on functions)
+	generateDropTriggersFromModifiedTables(d.modifiedTables, targetSchema, collector)
+
 	// Drop functions
 	generateDropFunctionsSQL(d.droppedFunctions, targetSchema, collector)
 

internal/diff/table.go

@@ -491,6 +491,8 @@ func generateTableSQL(table *ir.Table, targetSchema string) string {
 }
 
 // generateAlterTableStatements generates SQL statements for table modifications
+// Note: DroppedTriggers are skipped here because they are already processed in the DROP phase
+// (see generateDropTriggersFromModifiedTables in trigger.go)
 func (td *tableDiff) generateAlterTableStatements(targetSchema string, collector *diffCollector) {
 	// Drop constraints first (before dropping columns) - already sorted by the Diff operation
 	for _, constraint := range td.DroppedConstraints {
@@ -821,20 +823,8 @@ func (td *tableDiff) generateAlterTableStatements(targetSchema string, collector
 		collector.collect(context, sql)
 	}
 
-	// Drop triggers - already sorted by the Diff operation
-	for _, trigger := range td.DroppedTriggers {
-		tableName := getTableNameWithSchema(td.Table.Schema, td.Table.Name, targetSchema)
-		sql := fmt.Sprintf("DROP TRIGGER IF EXISTS %s ON %s;", trigger.Name, tableName)
-
-		context := &diffContext{
-			Type:                DiffTypeTableTrigger,
-			Operation:           DiffOperationDrop,
-			Path:                fmt.Sprintf("%s.%s.%s", td.Table.Schema, td.Table.Name, trigger.Name),
-			Source:              trigger,
-			CanRunInTransaction: true,
-		}
-		collector.collect(context, sql)
-	}
+	// Drop triggers - skipped here because they are already dropped in the DROP phase
+	// (see generateDropTriggersFromModifiedTables in trigger.go)
 
 	// Add triggers - already sorted by the Diff operation
 	for _, trigger := range td.AddedTriggers {

internal/diff/trigger.go

@@ -141,6 +141,39 @@ func generateCreateTriggersSQL(triggers []*ir.Trigger, targetSchema string, coll
 	}
 }
 
+// generateDropTriggersFromModifiedTables collects and drops all triggers from modified tables
+// This ensures triggers are dropped before their associated functions
+func generateDropTriggersFromModifiedTables(tables []*tableDiff, targetSchema string, collector *diffCollector) {
+	var allTriggers []*ir.Trigger
+
+	// Collect all dropped triggers from modified tables
+	for _, tableDiff := range tables {
+		for _, trigger := range tableDiff.DroppedTriggers {
+			allTriggers = append(allTriggers, trigger)
+		}
+	}
+
+	// Sort all triggers by name for consistent ordering
+	sort.Slice(allTriggers, func(i, j int) bool {
+		return allTriggers[i].Name < allTriggers[j].Name
+	})
+
+	// Generate DROP TRIGGER statements for all collected triggers
+	for _, trigger := range allTriggers {
+		tableName := getTableNameWithSchema(trigger.Schema, trigger.Table, targetSchema)
+		sql := fmt.Sprintf("DROP TRIGGER IF EXISTS %s ON %s;", trigger.Name, tableName)
+
+		context := &diffContext{
+			Type:                DiffTypeTableTrigger,
+			Operation:           DiffOperationDrop,
+			Path:                fmt.Sprintf("%s.%s.%s", trigger.Schema, trigger.Table, trigger.Name),
+			Source:              trigger,
+			CanRunInTransaction: true,
+		}
+		collector.collect(context, sql)
+	}
+}
+
 // generateTriggerSQLWithMode generates CREATE [OR REPLACE] TRIGGER or CREATE CONSTRAINT TRIGGER statement
 func generateTriggerSQLWithMode(trigger *ir.Trigger, targetSchema string) string {
 	// Build event list in standard order: INSERT, UPDATE, DELETE, TRUNCATE

testdata/diff/dependency/function_to_trigger/diff.sql

@@ -1,26 +1,19 @@
-CREATE TABLE IF NOT EXISTS users (
-    id SERIAL,
-    name text NOT NULL,
-    email text,
-    created_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    updated_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    CONSTRAINT users_pkey PRIMARY KEY (id),
-    CONSTRAINT users_email_key UNIQUE (email)
-);
+DROP TRIGGER IF EXISTS update_users_modified_time ON users;
+DROP FUNCTION IF EXISTS update_modified_time();
 
-CREATE OR REPLACE FUNCTION update_modified_time()
+CREATE OR REPLACE FUNCTION log_user_changes()
 RETURNS trigger
 LANGUAGE plpgsql
 SECURITY INVOKER
 VOLATILE
 AS $$
 BEGIN
-    NEW.updated_at = CURRENT_TIMESTAMP;
+    RAISE NOTICE 'User record changed: %', NEW.id;
     RETURN NEW;
 END;
 $$;
 
-CREATE OR REPLACE TRIGGER update_users_modified_time
-    BEFORE UPDATE ON users
+CREATE OR REPLACE TRIGGER log_users_trigger
+    AFTER INSERT OR UPDATE ON users
     FOR EACH ROW
-    EXECUTE FUNCTION update_modified_time();
+    EXECUTE FUNCTION log_user_changes();

testdata/diff/dependency/function_to_trigger/new.sql

@@ -1,4 +1,4 @@
--- Table with a trigger that depends on the function
+-- Table (unchanged)
 CREATE TABLE public.users (
     id serial PRIMARY KEY,
     name text NOT NULL,
@@ -7,17 +7,17 @@ CREATE TABLE public.users (
     updated_at timestamp DEFAULT CURRENT_TIMESTAMP
 );
 
--- Function that will be used by the trigger
-CREATE OR REPLACE FUNCTION public.update_modified_time()
+-- Different function for logging changes
+CREATE OR REPLACE FUNCTION public.log_user_changes()
 RETURNS trigger AS $$
 BEGIN
-    NEW.updated_at = CURRENT_TIMESTAMP;
+    RAISE NOTICE 'User record changed: %', NEW.id;
     RETURN NEW;
 END;
 $$ LANGUAGE plpgsql;
 
--- Trigger that depends on the function
-CREATE TRIGGER update_users_modified_time
-    BEFORE UPDATE ON public.users
+-- Different trigger that depends on the log function
+CREATE TRIGGER log_users_trigger
+    AFTER INSERT OR UPDATE ON public.users
     FOR EACH ROW
-    EXECUTE FUNCTION public.update_modified_time();
+    EXECUTE FUNCTION public.log_user_changes();

testdata/diff/dependency/function_to_trigger/old.sql

@@ -1 +1,23 @@
--- Empty schema (no objects)
+-- Table with a trigger that depends on the function
+CREATE TABLE public.users (
+    id serial PRIMARY KEY,
+    name text NOT NULL,
+    email text UNIQUE,
+    created_at timestamp DEFAULT CURRENT_TIMESTAMP,
+    updated_at timestamp DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Function that will be used by the trigger
+CREATE OR REPLACE FUNCTION public.update_modified_time()
+RETURNS trigger AS $$
+BEGIN
+    NEW.updated_at = CURRENT_TIMESTAMP;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+-- Trigger that depends on the function
+CREATE TRIGGER update_users_modified_time
+    BEFORE UPDATE ON public.users
+    FOR EACH ROW
+    EXECUTE FUNCTION public.update_modified_time();

testdata/diff/dependency/function_to_trigger/plan.json

@@ -3,28 +3,34 @@
   "pgschema_version": "1.4.0",
   "created_at": "1970-01-01T00:00:00Z",
   "source_fingerprint": {
-    "hash": "965b1131737c955e24c7f827c55bd78e4cb49a75adfd04229e0ba297376f5085"
+    "hash": "838be5bff5331655f93ff85bf9e620d007f6c664b57889a1efb31343310534c8"
   },
   "groups": [
     {
       "steps": [
         {
-          "sql": "CREATE TABLE IF NOT EXISTS users (\n    id SERIAL,\n    name text NOT NULL,\n    email text,\n    created_at timestamp DEFAULT CURRENT_TIMESTAMP,\n    updated_at timestamp DEFAULT CURRENT_TIMESTAMP,\n    CONSTRAINT users_pkey PRIMARY KEY (id),\n    CONSTRAINT users_email_key UNIQUE (email)\n);",
-          "type": "table",
-          "operation": "create",
-          "path": "public.users"
+          "sql": "DROP TRIGGER IF EXISTS update_users_modified_time ON users;",
+          "type": "table.trigger",
+          "operation": "drop",
+          "path": "public.users.update_users_modified_time"
         },
         {
-          "sql": "CREATE OR REPLACE FUNCTION update_modified_time()\nRETURNS trigger\nLANGUAGE plpgsql\nSECURITY INVOKER\nVOLATILE\nAS $$\nBEGIN\n    NEW.updated_at = CURRENT_TIMESTAMP;\n    RETURN NEW;\nEND;\n$$;",
+          "sql": "DROP FUNCTION IF EXISTS update_modified_time();",
           "type": "function",
-          "operation": "create",
+          "operation": "drop",
           "path": "public.update_modified_time"
         },
         {
-          "sql": "CREATE OR REPLACE TRIGGER update_users_modified_time\n    BEFORE UPDATE ON users\n    FOR EACH ROW\n    EXECUTE FUNCTION update_modified_time();",
+          "sql": "CREATE OR REPLACE FUNCTION log_user_changes()\nRETURNS trigger\nLANGUAGE plpgsql\nSECURITY INVOKER\nVOLATILE\nAS $$\nBEGIN\n    RAISE NOTICE 'User record changed: %', NEW.id;\n    RETURN NEW;\nEND;\n$$;",
+          "type": "function",
+          "operation": "create",
+          "path": "public.log_user_changes"
+        },
+        {
+          "sql": "CREATE OR REPLACE TRIGGER log_users_trigger\n    AFTER INSERT OR UPDATE ON users\n    FOR EACH ROW\n    EXECUTE FUNCTION log_user_changes();",
           "type": "table.trigger",
           "operation": "create",
-          "path": "public.users.update_users_modified_time"
+          "path": "public.users.log_users_trigger"
         }
       ]
     }

testdata/diff/dependency/function_to_trigger/plan.sql

@@ -1,26 +1,20 @@
-CREATE TABLE IF NOT EXISTS users (
-    id SERIAL,
-    name text NOT NULL,
-    email text,
-    created_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    updated_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    CONSTRAINT users_pkey PRIMARY KEY (id),
-    CONSTRAINT users_email_key UNIQUE (email)
-);
+DROP TRIGGER IF EXISTS update_users_modified_time ON users;
 
-CREATE OR REPLACE FUNCTION update_modified_time()
+DROP FUNCTION IF EXISTS update_modified_time();
+
+CREATE OR REPLACE FUNCTION log_user_changes()
 RETURNS trigger
 LANGUAGE plpgsql
 SECURITY INVOKER
 VOLATILE
 AS $$
 BEGIN
-    NEW.updated_at = CURRENT_TIMESTAMP;
+    RAISE NOTICE 'User record changed: %', NEW.id;
     RETURN NEW;
 END;
 $$;
 
-CREATE OR REPLACE TRIGGER update_users_modified_time
-    BEFORE UPDATE ON users
+CREATE OR REPLACE TRIGGER log_users_trigger
+    AFTER INSERT OR UPDATE ON users
     FOR EACH ROW
-    EXECUTE FUNCTION update_modified_time();
+    EXECUTE FUNCTION log_user_changes();

testdata/diff/dependency/function_to_trigger/plan.txt

@@ -1,42 +1,38 @@
-Plan: 2 to add.
+Plan: 1 to add, 1 to modify, 1 to drop.
 
 Summary by type:
-  functions: 1 to add
-  tables: 1 to add
+  functions: 1 to add, 1 to drop
+  tables: 1 to modify
 
 Functions:
-  + update_modified_time
+  + log_user_changes
+  - update_modified_time
 
 Tables:
-  + users
-    + update_users_modified_time (trigger)
+  ~ users
+    + log_users_trigger (trigger)
+    - update_users_modified_time (trigger)
 
 DDL to be executed:
 --------------------------------------------------
 
-CREATE TABLE IF NOT EXISTS users (
-    id SERIAL,
-    name text NOT NULL,
-    email text,
-    created_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    updated_at timestamp DEFAULT CURRENT_TIMESTAMP,
-    CONSTRAINT users_pkey PRIMARY KEY (id),
-    CONSTRAINT users_email_key UNIQUE (email)
-);
-
-CREATE OR REPLACE FUNCTION update_modified_time()
+DROP TRIGGER IF EXISTS update_users_modified_time ON users;
+
+DROP FUNCTION IF EXISTS update_modified_time();
+
+CREATE OR REPLACE FUNCTION log_user_changes()
 RETURNS trigger
 LANGUAGE plpgsql
 SECURITY INVOKER
 VOLATILE
 AS $$
 BEGIN
-    NEW.updated_at = CURRENT_TIMESTAMP;
+    RAISE NOTICE 'User record changed: %', NEW.id;
     RETURN NEW;
 END;
 $$;
 
-CREATE OR REPLACE TRIGGER update_users_modified_time
-    BEFORE UPDATE ON users
+CREATE OR REPLACE TRIGGER log_users_trigger
+    AFTER INSERT OR UPDATE ON users
     FOR EACH ROW
-    EXECUTE FUNCTION update_modified_time();
+    EXECUTE FUNCTION log_user_changes();