fix: normalize schema qualifier in function arguments

ir/inspector.go

@@ -915,7 +915,7 @@ func (i *Inspector) buildFunctions(ctx context.Context, schema *IR, targetSchema
 
 		// Parse parameters from the complete signature provided by pg_get_function_arguments()
 		// This signature includes all parameter information including modes, names, types, and defaults
-		parameters := i.parseParametersFromSignature(signature)
+		parameters := i.parseParametersFromSignature(signature, schemaName)
 
 		function := &Function{
 			Schema:            schemaName,
@@ -1006,7 +1006,7 @@ func splitParameterString(signature string) []string {
 // parseParametersFromSignature parses function signature string into Parameter structs
 // Example signature: "order_id integer, discount_percent numeric DEFAULT 0"
 // Or with modes: "IN order_id integer, OUT result integer"
-func (i *Inspector) parseParametersFromSignature(signature string) []*Parameter {
+func (i *Inspector) parseParametersFromSignature(signature string, routineSchema string) []*Parameter {
 	if signature == "" {
 		return nil
 	}
@@ -1060,13 +1060,54 @@ func (i *Inspector) parseParametersFromSignature(signature string) []*Parameter
 			param.DataType = remainingParts[0]
 		}
 
+		// Normalize type by stripping schema prefix if it matches the routine's schema
+		// This ensures consistent comparison between database and source SQL representations
+		param.DataType = i.stripSameSchemaPrefix(param.DataType, routineSchema)
+
 		parameters = append(parameters, param)
 		position++
 	}
 
 	return parameters
 }
 
+// stripSameSchemaPrefix removes schema qualification from a type name if the schema
+// matches the routine's schema. This normalizes PostgreSQL's behavior of returning
+// schema-qualified type names (e.g., "public.order_status") to unqualified names
+// (e.g., "order_status") when the type is in the same schema as the function/procedure.
+//
+// Cross-schema type references are preserved (e.g., "utils.priority_level" stays qualified
+// when the function is in the "public" schema).
+//
+// This ensures consistent comparison between database inspection (which may return qualified
+// names) and source SQL (which typically uses unqualified names for same-schema types).
+func (i *Inspector) stripSameSchemaPrefix(typeName, routineSchema string) string {
+	if typeName == "" || routineSchema == "" {
+		return typeName
+	}
+
+	// Remove quotes from schema name for comparison
+	unquotedSchema := routineSchema
+	if strings.HasPrefix(routineSchema, `"`) && strings.HasSuffix(routineSchema, `"`) {
+		unquotedSchema = routineSchema[1 : len(routineSchema)-1]
+	}
+
+	// Handle quoted schema prefix: "schema".typename
+	quotedPrefix := fmt.Sprintf(`"%s".`, unquotedSchema)
+	if strings.HasPrefix(typeName, quotedPrefix) {
+		return typeName[len(quotedPrefix):]
+	}
+
+	// Handle unquoted schema prefix: schema.typename
+	unquotedPrefix := unquotedSchema + "."
+	if strings.HasPrefix(typeName, unquotedPrefix) {
+		return typeName[len(unquotedPrefix):]
+	}
+
+	// No matching prefix - return as-is (could be cross-schema type or already unqualified)
+	return typeName
+}
+
 // lookupTypeNameFromOID converts PostgreSQL type OID to type name
 func (i *Inspector) lookupTypeNameFromOID(oid int64) string {
 	// Common type OID mappings (can be extended as needed)
@@ -1119,7 +1160,7 @@ func (i *Inspector) buildProcedures(ctx context.Context, schema *IR, targetSchem
 		dbSchema := schema.getOrCreateSchema(schemaName)
 
 		// Parse parameters from signature (same approach as functions)
-		parameters := i.parseParametersFromSignature(signature)
+		parameters := i.parseParametersFromSignature(signature, schemaName)
 
 		procedure := &Procedure{
 			Schema:     schemaName,

testdata/diff/create_function/alter_function_same_signature/diff.sql

@@ -1,6 +1,8 @@
 CREATE OR REPLACE FUNCTION process_order(
     order_id integer,
-    discount_percent numeric DEFAULT 0
+    discount_percent numeric DEFAULT 0,
+    status order_status DEFAULT 'pending',
+    priority utils.priority_level DEFAULT 'medium'
 )
 RETURNS numeric
 LANGUAGE plpgsql
@@ -12,6 +14,7 @@ DECLARE
     tax_rate numeric := 0.08;
 BEGIN
     -- Different logic: calculate with tax instead of just discount
+    -- Status and priority parameters are available but not used in this simplified version
     SELECT price INTO base_price FROM products WHERE id = order_id;
     RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);
 END;

testdata/diff/create_function/alter_function_same_signature/new.sql

@@ -1,6 +1,10 @@
+CREATE TYPE order_status AS ENUM ('pending', 'processing', 'completed', 'cancelled');
+
 CREATE FUNCTION process_order(
     order_id integer,
-    discount_percent numeric DEFAULT 0
+    discount_percent numeric DEFAULT 0,
+    status order_status DEFAULT 'pending',
+    priority utils.priority_level DEFAULT 'medium'
 )
 RETURNS numeric
 LANGUAGE plpgsql
@@ -12,6 +16,7 @@ DECLARE
     tax_rate numeric := 0.08;
 BEGIN
     -- Different logic: calculate with tax instead of just discount
+    -- Status and priority parameters are available but not used in this simplified version
     SELECT price INTO base_price FROM products WHERE id = order_id;
     RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);
 END;

testdata/diff/create_function/alter_function_same_signature/old.sql

@@ -1,6 +1,10 @@
+CREATE TYPE order_status AS ENUM ('pending', 'processing', 'completed', 'cancelled');
+
 CREATE FUNCTION process_order(
     order_id integer,
-    discount_percent numeric DEFAULT 0
+    discount_percent numeric DEFAULT 0,
+    status order_status DEFAULT 'pending',
+    priority utils.priority_level DEFAULT 'medium'
 )
 RETURNS numeric
 LANGUAGE plpgsql

testdata/diff/create_function/alter_function_same_signature/plan.json

@@ -1,15 +1,15 @@
 {
   "version": "1.0.0",
-  "pgschema_version": "1.4.0",
+  "pgschema_version": "1.4.1",
   "created_at": "1970-01-01T00:00:00Z",
   "source_fingerprint": {
-    "hash": "60f55cc9364a4c46fec3d3c3b819f5507eea75c2667985f2a9c1a2954f786e4e"
+    "hash": "6d0c7bd072cf940b17ecae1b64566b63a06bd9cd0aaf2c69a12af2fe77ae6d47"
   },
   "groups": [
     {
       "steps": [
         {
-          "sql": "CREATE OR REPLACE FUNCTION process_order(\n    order_id integer,\n    discount_percent numeric DEFAULT 0\n)\nRETURNS numeric\nLANGUAGE plpgsql\nSECURITY INVOKER\nSTABLE\nAS $$\nDECLARE\n    base_price numeric;\n    tax_rate numeric := 0.08;\nBEGIN\n    -- Different logic: calculate with tax instead of just discount\n    SELECT price INTO base_price FROM products WHERE id = order_id;\n    RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);\nEND;\n$$;",
+          "sql": "CREATE OR REPLACE FUNCTION process_order(\n    order_id integer,\n    discount_percent numeric DEFAULT 0,\n    status order_status DEFAULT 'pending',\n    priority utils.priority_level DEFAULT 'medium'\n)\nRETURNS numeric\nLANGUAGE plpgsql\nSECURITY INVOKER\nSTABLE\nAS $$\nDECLARE\n    base_price numeric;\n    tax_rate numeric := 0.08;\nBEGIN\n    -- Different logic: calculate with tax instead of just discount\n    -- Status and priority parameters are available but not used in this simplified version\n    SELECT price INTO base_price FROM products WHERE id = order_id;\n    RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);\nEND;\n$$;",
           "type": "function",
           "operation": "alter",
           "path": "public.process_order"

testdata/diff/create_function/alter_function_same_signature/plan.sql

@@ -1,6 +1,8 @@
 CREATE OR REPLACE FUNCTION process_order(
     order_id integer,
-    discount_percent numeric DEFAULT 0
+    discount_percent numeric DEFAULT 0,
+    status order_status DEFAULT 'pending',
+    priority utils.priority_level DEFAULT 'medium'
 )
 RETURNS numeric
 LANGUAGE plpgsql
@@ -12,6 +14,7 @@ DECLARE
     tax_rate numeric := 0.08;
 BEGIN
     -- Different logic: calculate with tax instead of just discount
+    -- Status and priority parameters are available but not used in this simplified version
     SELECT price INTO base_price FROM products WHERE id = order_id;
     RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);
 END;

testdata/diff/create_function/alter_function_same_signature/plan.txt

@@ -11,7 +11,9 @@ DDL to be executed:
 
 CREATE OR REPLACE FUNCTION process_order(
     order_id integer,
-    discount_percent numeric DEFAULT 0
+    discount_percent numeric DEFAULT 0,
+    status order_status DEFAULT 'pending',
+    priority utils.priority_level DEFAULT 'medium'
 )
 RETURNS numeric
 LANGUAGE plpgsql
@@ -23,6 +25,7 @@ DECLARE
     tax_rate numeric := 0.08;
 BEGIN
     -- Different logic: calculate with tax instead of just discount
+    -- Status and priority parameters are available but not used in this simplified version
     SELECT price INTO base_price FROM products WHERE id = order_id;
     RETURN base_price * (1 - discount_percent / 100) * (1 + tax_rate);
 END;

testdata/diff/create_function/alter_function_same_signature/setup.sql

@@ -0,0 +1,4 @@
+-- Create utils schema with a custom type for cross-schema testing
+CREATE SCHEMA IF NOT EXISTS utils;
+
+CREATE TYPE utils.priority_level AS ENUM ('low', 'medium', 'high', 'critical');