Issue #20196: Fixed a bug where Argument Clinic did not generate correct

parsing code for functions with positional-only parameters where all arguments
are optional.

2 files changed, 10 insertions, 0 deletions

diff --git a/Misc/NEWS b/Misc/NEWS
index d73137e..d6be619 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -72,6 +72,10 @@ Tests
 Tools/Demos
 -----------
 
+- Issue #20196: Fixed a bug where Argument Clinic did not generate correct
+  parsing code for functions with positional-only parameters where all arguments
+  are optional.
+
 - Issue #18960: 2to3 and the findnocoding.py script now ignore the source
   encoding declaration on the second line if the first line contains anything
   except a comment.
diff --git a/Tools/clinic/clinic.py b/Tools/clinic/clinic.py
index 421b9e3..cd7c597 100755
--- a/Tools/clinic/clinic.py
+++ b/Tools/clinic/clinic.py
@@ -591,6 +591,12 @@ static {impl_return_type}
             count_min = min(count_min, count)
             count_max = max(count_max, count)
 
+            if count == 0:
+                add("""    case 0:
+        break;
+""")
+                continue
+
             group_ids = {p.group for p in subset}  # eliminate duplicates
             d = {}
             d['count'] = count