Handle strict filter errors consistently

liquid/context.go

@@ -297,11 +297,13 @@ func (c *Context) HandleError(err error, lineNumber *int) string {
 				if _, ok := err.(*StandardError); !ok {
 					if _, ok := err.(*ArgumentError); !ok {
 						if _, ok := err.(*UndefinedVariable); !ok {
-							if _, ok := err.(*DisabledError); !ok {
-								if _, ok := err.(*MemoryError); !ok {
-									if _, ok := err.(*FileSystemError); !ok {
-										if _, ok := err.(*StackLevelError); !ok {
-											liquidErr = NewInternalError("internal")
+							if _, ok := err.(*UndefinedFilter); !ok {
+								if _, ok := err.(*DisabledError); !ok {
+									if _, ok := err.(*MemoryError); !ok {
+										if _, ok := err.(*FileSystemError); !ok {
+											if _, ok := err.(*StackLevelError); !ok {
+												liquidErr = NewInternalError("internal")
+											}
 										}
 									}
 								}
@@ -396,7 +398,9 @@ func (c *Context) HandleError(err error, lineNumber *int) string {
 func (c *Context) Invoke(method string, obj interface{}, args ...interface{}) interface{} {
 	result, err := c.Strainer().Invoke(method, append([]interface{}{obj}, args...)...)
 	if err != nil {
-		// Handle error
+		if c.strictFilters {
+			panic(err)
+		}
 		return obj
 	}
 	return ToLiquid(result)

liquid/context_test.go

@@ -197,6 +197,32 @@ func TestContextStrictVariables(t *testing.T) {
 	}()
 }
 
+func TestContextInvokeStrictFiltersUnknownPanics(t *testing.T) {
+	ctx := NewContext()
+	ctx.SetStrictFilters(true)
+
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fatal("Expected panic for undefined filter in strict mode")
+		} else {
+			if _, ok := r.(*UndefinedFilter); !ok {
+				t.Fatalf("Expected UndefinedFilter panic, got %T", r)
+			}
+		}
+	}()
+
+	ctx.Invoke("NonexistentFilter", "arg")
+}
+
+func TestContextInvokeNonStrictFiltersUnknownReturnsOriginal(t *testing.T) {
+	ctx := NewContext()
+
+	result := ctx.Invoke("NonexistentFilter", "arg")
+	if result != "arg" {
+		t.Errorf("Expected original object in non-strict mode, got %v", result)
+	}
+}
+
 func TestContextResourceLimits(t *testing.T) {
 	ctx := NewContext()
 	rl := ctx.ResourceLimits()

liquid/variable.go

@@ -408,6 +408,8 @@ func (v *Variable) RenderToOutputBuffer(context TagContext, output *string) {
 				err = e
 			case *StackLevelError:
 				err = e
+			case *UndefinedFilter:
+				err = e
 			case *Error:
 				err = e
 			case error: