Do not validate options when finding non-matching

mesonbuild/interpreter.py

@@ -2476,13 +2476,10 @@ def _redetect_machines(self):
 
     # TODO: Why is this in interpreter.py and not CoreData or Environment?
     def get_non_matching_default_options(self) -> T.Iterator[T.Tuple[str, str, coredata.UserOption]]:
-        env = self.environment
         for def_opt_name, def_opt_value in self.project_default_options.items():
             cur_opt_value = self.coredata.options.get(def_opt_name)
-            if cur_opt_value is not None:
-                def_opt_value = env.coredata.validate_option_value(def_opt_name, def_opt_value)
-                if def_opt_value != cur_opt_value.value:
-                    yield (str(def_opt_name), def_opt_value, cur_opt_value)
+            if cur_opt_value is not None and def_opt_value != cur_opt_value.value:
+                yield (str(def_opt_name), def_opt_value, cur_opt_value)
 
     def build_func_dict(self):
         self.funcs.update({'add_global_arguments': self.func_add_global_arguments,

test cases/common/236 invalid standard overriden to valid/main.c

@@ -0,0 +1,3 @@
+int main(void) {
+    return 0;
+}

test cases/common/236 invalid standard overriden to valid/meson.build

@@ -0,0 +1,8 @@
+project(
+  'invalid C standard overriden to valid one',
+  'c',
+  default_options : ['c_std=invalid99'],
+)
+
+exe = executable('main', 'main.c')
+test('main', exe)

test cases/common/236 invalid standard overriden to valid/test.json

@@ -0,0 +1,9 @@
+{
+  "matrix": {
+    "options": {
+      "c_std": [
+        { "val": "c89" }
+      ]
+    }
+  }
+}