Fix a crash in the coverage extension when module contents are not found (#11702)

Signed-off-by: Stephen Finucane <[email protected]>
Co-authored-by: Stephen Finucane <[email protected]>
Authored-by: Stephen Finucane <[email protected]>

Author: Lonami

CHANGES.rst

@@ -41,6 +41,8 @@ Bugs fixed
   Patch by Bénédikt Tran.
 * #11697: HTML Search: add 'noindex' meta robots tag.
   Patch by James Addison.
+* #11678: Fix a possible ``ZeroDivisionError`` in ``sphinx.ext.coverage``.
+  Patch by Stephen Finucane.
 
 Testing
 -------

sphinx/ext/coverage.py

@@ -290,11 +290,15 @@ def _write_py_statistics(self, op: TextIO) -> None:
                 value = 100.0
 
             table.append([module, '%.2f%%' % value, '%d' % len(self.py_undocumented[module])])
-        table.append([
-            'TOTAL',
-            f'{100 * len(all_documented_objects) / len(all_objects):.2f}%',
-            f'{len(all_objects) - len(all_documented_objects)}',
-        ])
+
+        if all_objects:
+            table.append([
+                'TOTAL',
+                f'{100 * len(all_documented_objects) / len(all_objects):.2f}%',
+                f'{len(all_objects) - len(all_documented_objects)}',
+            ])
+        else:
+            table.append(['TOTAL', '100', '0'])
 
         for line in _write_table(table):
             op.write(f'{line}\n')