Correctly report if an extension raises a `TypeError`.

Also Raise a `KeyError` when attempting to delete a nonexistent key from the extension registry.

1 files changed, 12 insertions, 9 deletions

diff --git a/markdown/extensions/__init__.py b/markdown/extensions/__init__.py
index 010e310..4bc8e5f 100644
--- a/markdown/extensions/__init__.py
+++ b/markdown/extensions/__init__.py
@@ -75,15 +75,18 @@ class Extension:
         md = args[0]
         try:
             self.extendMarkdown(md)
-        except TypeError:
-            # Must be a 2.x extension. Pass in a dumby md_globals.
-            self.extendMarkdown(md, {})
-            warnings.warn(
-                "The 'md_globals' parameter of '{}.{}.extendMarkdown' is "
-                "deprecated.".format(self.__class__.__module__, self.__class__.__name__),
-                category=DeprecationWarning,
-                stacklevel=2
-            )
+        except TypeError as e:
+            if "missing 1 required positional argument" in str(e):
+                # Must be a 2.x extension. Pass in a dumby md_globals.
+                self.extendMarkdown(md, {})
+                warnings.warn(
+                    "The 'md_globals' parameter of '{}.{}.extendMarkdown' is "
+                    "deprecated.".format(self.__class__.__module__, self.__class__.__name__),
+                    category=DeprecationWarning,
+                    stacklevel=2
+                )
+            else:
+                raise
 
     def extendMarkdown(self, md):
         """