refactor: improve suggestion message computation and punctuation handling

Author: krisztian-gajdar

Lib/traceback.py

@@ -1099,7 +1099,10 @@ def __init__(self, exc_type, exc_value, exc_traceback, *, limit=None,
                 self._is_syntax_error = True
                 self._exc_metadata = getattr(exc_value, "_metadata", None)
             elif suggestion := _compute_suggestion_message(exc_type, exc_value, exc_traceback):
-                punctuation = "" if self._str.rstrip().endswith(('.', '!')) else "."
+                if self._str.endswith(('.', '?', '!', '...')):
+                    punctuation = ''
+                else:
+                    punctuation = '.'
                 self._str += f"{punctuation} {suggestion}"
         else:
             self.exc_type_qualname = None
@@ -1710,23 +1713,35 @@ def _compute_suggestion_error(exc_value, tb, wrong_name):
     return suggestion
 
 
-def _compute_suggestion_message(exc_type, exc_value, exc_traceback) -> str | None:
-    if issubclass(exc_type, ModuleNotFoundError) and \
-        sys.flags.no_site and \
-        getattr(exc_value, "name", None) not in sys.stdlib_module_names:
-            return ("Site initialization is disabled, did you forget to "
-                "add the site-packages directory to sys.path?")
+def _compute_suggestion_message(exc_type, exc_value, exc_traceback):
+    if (
+        issubclass(exc_type, ModuleNotFoundError)
+        and sys.flags.no_site
+        and getattr(exc_value, "name", None) not in sys.stdlib_module_names
+    ):
+        return ("Site initialization is disabled, did you forget to "
+            "add the site-packages directory to sys.path?")
     if issubclass(exc_type, (ImportError, NameError, AttributeError)):
-        name_attribute = "name_from" if issubclass(exc_type, ImportError) else "name"
-        wrong_name = getattr(exc_value, name_attribute, None)
+        if issubclass(exc_type, ImportError):
+            wrong_name = getattr(exc_value, "name_from", None) 
+        else:
+            wrong_name = getattr(exc_value, "name", None) 
         if wrong_name:
-            suggestion_error = _compute_suggestion_error(exc_value, exc_traceback, wrong_name)
-            suggestion_text = f"Did you mean: '{suggestion_error}'?" if suggestion_error else None
-            if issubclass(exc_type, NameError) and wrong_name in sys.stdlib_module_names:
-                if suggestion_error:
-                    return f"{suggestion_text} Or did you forget to import '{wrong_name}'?"
-                return f"Did you forget to import '{wrong_name}'?"
-            return suggestion_text
+            other_name = _compute_suggestion_error(
+                exc_value, exc_traceback, wrong_name
+            )
+            maybe_builtin_import = (
+                issubclass(exc_type, NameError)
+                and wrong_name in sys.stdlib_module_names
+            )
+            if not other_name:
+                if maybe_builtin_import:
+                    return f"Did you forget to import '{wrong_name}'?"
+                return None
+            text = f"Did you mean: '{other_name}'?"
+            if maybe_builtin_import:
+                return f"{text} Or did you forget to import '{wrong_name}'?"
+            return text
     return None