better filtering of builtins in check_api

devtools/check-api

@@ -5,6 +5,7 @@ import os
 import os.path
 import subprocess
 import sys
+import types
 from collections import OrderedDict
 
 # import koji code from our checkout
@@ -109,23 +110,28 @@ def dump_module(mod):
         _type = str(type(value))
         if '__future__' in _type:
             continue
+        if type(value) in (types.BuiltinFunctionType, types.BuiltinMethodType):
+            vinfo['is_external'] = True
+            vinfo['is_builtin'] = True
         vinfo['type'] = str(type(value))
         info[name] = vinfo
         if inspect.ismodule(value):
             vinfo['is_module'] = True
             continue
-        try:
-            if inspect.getsourcefile(value) != file:
-                # don't dig any deeper if it isn't defined in the module
+        if inspect.isclass(value):
+            if 'builtins' in value.__module__:
+                vinfo['is_external'] = True
+                vinfo['is_builtin'] = True
+                continue
+            elif inspect.getsourcefile(value) != file:
                 vinfo['is_external'] = True
                 continue
-        except TypeError:
-            # getsourcefile fails for numerous types
-            pass
-        if inspect.isclass(value):
             vinfo['is_class'] = True
             vinfo.update(dump_class(value))
         elif inspect.isfunction(value):
+            if inspect.getsourcefile(value) != file:
+                vinfo['is_external'] = True
+                continue
             vinfo['is_function'] = True
             vinfo.update(dump_func(value))
     return info
@@ -255,6 +261,9 @@ def compare_mod_global(mod, name, old, new):
 
 
 def compare_class(cls, old, new):
+    if not new.get('is_class'):
+        error(f'No longer a class: {cls}')
+        return
     names1 = set(old['members'])
     names2 = set(new['members'])
     added = names2 - names1