feat: support SET search_path for functions

internal/diff/function.go

@@ -223,6 +223,13 @@ func generateFunctionSQL(function *ir.Function, targetSchema string) string {
 	}
 	// Note: Don't output PARALLEL UNSAFE (it's the default)
 
+	// Add SET search_path if specified
+	// Note: Output without outer quotes to handle multi-schema paths correctly
+	// e.g., "SET search_path = pg_catalog, public" not "SET search_path = 'pg_catalog, public'"
+	if function.SearchPath != "" {
+		stmt.WriteString(fmt.Sprintf("\nSET search_path = %s", function.SearchPath))
+	}
+
 	// Add the function body
 	if function.Definition != "" {
 		// Check if this uses RETURN clause syntax (PG14+)
@@ -393,6 +400,9 @@ func functionsEqual(old, new *ir.Function) bool {
 	if old.Parallel != new.Parallel {
 		return false
 	}
+	if old.SearchPath != new.SearchPath {
+		return false
+	}
 	if old.Comment != new.Comment {
 		return false
 	}
@@ -439,6 +449,9 @@ func functionsEqualExceptComment(old, new *ir.Function) bool {
 	if old.Parallel != new.Parallel {
 		return false
 	}
+	if old.SearchPath != new.SearchPath {
+		return false
+	}
 	// Note: We intentionally do NOT compare Comment here
 
 	oldInputParams := filterNonTableParameters(old.Parameters)

ir/inspector.go

@@ -934,6 +934,12 @@ func (i *Inspector) buildFunctions(ctx context.Context, schema *IR, targetSchema
 		// This signature includes all parameter information including modes, names, types, and defaults
 		parameters := i.parseParametersFromSignature(signature, schemaName)
 
+		// Handle search_path
+		searchPath := ""
+		if fn.SearchPath.Valid {
+			searchPath = fn.SearchPath.String
+		}
+
 		function := &Function{
 			Schema:            schemaName,
 			Name:              functionName,
@@ -947,6 +953,7 @@ func (i *Inspector) buildFunctions(ctx context.Context, schema *IR, targetSchema
 			IsSecurityDefiner: isSecurityDefiner,
 			IsLeakproof:       isLeakproof,
 			Parallel:          parallelMode,
+			SearchPath:        searchPath,
 		}
 
 		// Use name(arguments) as key to support function overloading

ir/ir.go

@@ -136,6 +136,7 @@ type Function struct {
 	IsSecurityDefiner bool         `json:"is_security_definer,omitempty"` // SECURITY DEFINER
 	IsLeakproof       bool         `json:"is_leakproof,omitempty"`        // LEAKPROOF
 	Parallel          string       `json:"parallel,omitempty"`            // SAFE, UNSAFE, RESTRICTED
+	SearchPath        string       `json:"search_path,omitempty"`         // SET search_path value
 }
 
 // GetArguments returns the function arguments string (types only) for function identification.

ir/queries/queries.sql

@@ -979,7 +979,8 @@ SELECT
     p.proisstrict AS is_strict,
     p.prosecdef AS is_security_definer,
     p.proleakproof AS is_leakproof,
-    p.proparallel AS parallel_mode
+    p.proparallel AS parallel_mode,
+    (SELECT substring(cfg FROM 'search_path=(.*)') FROM unnest(p.proconfig) AS cfg WHERE cfg LIKE 'search_path=%') AS search_path
 FROM information_schema.routines r
 LEFT JOIN pg_proc p ON p.proname = r.routine_name
     AND p.pronamespace = (SELECT oid FROM pg_namespace WHERE nspname = r.routine_schema)

testdata/diff/create_function/add_function/diff.sql

@@ -38,6 +38,7 @@ STRICT
 SECURITY DEFINER
 LEAKPROOF
 PARALLEL RESTRICTED
+SET search_path = pg_catalog, public
 AS $$
 DECLARE
     total numeric;

testdata/diff/create_function/add_function/new.sql

@@ -20,6 +20,7 @@ STRICT
 SECURITY DEFINER
 LEAKPROOF
 PARALLEL RESTRICTED
+SET search_path = pg_catalog, public
 AS $$
 DECLARE
     total numeric;

testdata/diff/create_function/add_function/plan.json

@@ -21,7 +21,7 @@
           "path": "public.mask_sensitive_data"
         },
         {
-          "sql": "CREATE OR REPLACE FUNCTION process_order(\n    order_id integer,\n    discount_percent numeric DEFAULT 0,\n    priority_level integer DEFAULT 1,\n    note varchar DEFAULT '',\n    status text DEFAULT 'pending',\n    apply_tax boolean DEFAULT true,\n    is_priority boolean DEFAULT false,\n    expiry_date date DEFAULT (CURRENT_DATE + '1 year'::interval)\n)\nRETURNS numeric\nLANGUAGE plpgsql\nVOLATILE\nSTRICT\nSECURITY DEFINER\nLEAKPROOF\nPARALLEL RESTRICTED\nAS $$\nDECLARE\n    total numeric;\nBEGIN\n    SELECT amount INTO total FROM orders WHERE id = order_id;\n    RETURN total - (total * discount_percent / 100);\nEND;\n$$;",
+          "sql": "CREATE OR REPLACE FUNCTION process_order(\n    order_id integer,\n    discount_percent numeric DEFAULT 0,\n    priority_level integer DEFAULT 1,\n    note varchar DEFAULT '',\n    status text DEFAULT 'pending',\n    apply_tax boolean DEFAULT true,\n    is_priority boolean DEFAULT false,\n    expiry_date date DEFAULT (CURRENT_DATE + '1 year'::interval)\n)\nRETURNS numeric\nLANGUAGE plpgsql\nVOLATILE\nSTRICT\nSECURITY DEFINER\nLEAKPROOF\nPARALLEL RESTRICTED\nSET search_path = pg_catalog, public\nAS $$\nDECLARE\n    total numeric;\nBEGIN\n    SELECT amount INTO total FROM orders WHERE id = order_id;\n    RETURN total - (total * discount_percent / 100);\nEND;\n$$;",
           "type": "function",
           "operation": "create",
           "path": "public.process_order"

testdata/diff/create_function/add_function/plan.sql

@@ -38,6 +38,7 @@ STRICT
 SECURITY DEFINER
 LEAKPROOF
 PARALLEL RESTRICTED
+SET search_path = pg_catalog, public
 AS $$
 DECLARE
     total numeric;

testdata/diff/create_function/add_function/plan.txt

@@ -51,6 +51,7 @@ STRICT
 SECURITY DEFINER
 LEAKPROOF
 PARALLEL RESTRICTED
+SET search_path = pg_catalog, public
 AS $$
 DECLARE
     total numeric;