https://github.com/python/cpython/commit/ed4f78a4b318e57c9cadad2296c8b977431df6b3
commit: ed4f78a4b318e57c9cadad2296c8b977431df6b3
branch: main
author: Pablo Galindo Salgado <[email protected]>
committer: pablogsal <[email protected]>
date: 2025-12-06T21:09:35Z
summary:
gh-142236: Fix incorrect keyword suggestions for syntax errors (#142328)
The keyword typo suggestion mechanism in traceback would incorrectly
suggest replacements when the extracted source code was merely incomplete
rather than containing an actual typo. For example, when a missing comma
caused a syntax error, the system would suggest replacing 'print' with
'not' because the incomplete code snippet happened to pass validation.
The fix adds a validation step that first checks whether the original
extracted code raises a SyntaxError. If the code compiles successfully
or is simply incomplete (compile_command returns None), the function
returns early since there is no way to verify that a keyword replacement
would actually fix the problem.
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2025-12-06-00-16-43.gh-issue-142236.m3EF9E.rst
M Lib/test/test_traceback.py
M Lib/traceback.py
diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index 3876f1a74bbc1a..d107ad925941fe 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -1784,6 +1784,23 @@ def test_keyword_suggestions_from_command_string(self):
stderr_text = stderr.decode('utf-8')
self.assertIn(f"Did you mean '{expected_kw}'", stderr_text)
+ def test_no_keyword_suggestion_for_comma_errors(self):
+ # When the parser identifies a missing comma, don't suggest
+ # bogus keyword replacements like 'print' -> 'not'
+ code = '''\
+import sys
+print(
+ "line1"
+ "line2"
+ file=sys.stderr
+)
+'''
+ source = textwrap.dedent(code).strip()
+ rc, stdout, stderr = assert_python_failure('-c', source)
+ stderr_text = stderr.decode('utf-8')
+ self.assertIn("Perhaps you forgot a comma", stderr_text)
+ self.assertNotIn("Did you mean", stderr_text)
+
@requires_debug_ranges()
@force_not_colorized_test_class
class PurePythonTracebackErrorCaretTests(
diff --git a/Lib/traceback.py b/Lib/traceback.py
index 8a3e0f77e765dc..c1052adeed25a1 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -1340,6 +1340,15 @@ def _find_keyword_typos(self):
if len(error_code) > 1024:
return
+ # If the original code doesn't raise SyntaxError, we can't validate
+ # that a keyword replacement actually fixes anything
+ try:
+ codeop.compile_command(error_code, symbol="exec",
flags=codeop.PyCF_ONLY_AST)
+ except SyntaxError:
+ pass # Good - the original code has a syntax error we might fix
+ else:
+ return # Original code compiles or is incomplete - can't validate
fixes
+
error_lines = error_code.splitlines()
tokens = tokenize.generate_tokens(io.StringIO(error_code).readline)
tokens_left_to_process = 10
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2025-12-06-00-16-43.gh-issue-142236.m3EF9E.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2025-12-06-00-16-43.gh-issue-142236.m3EF9E.rst
new file mode 100644
index 00000000000000..b5c6a27fd6a259
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2025-12-06-00-16-43.gh-issue-142236.m3EF9E.rst
@@ -0,0 +1,4 @@
+Fix incorrect keyword suggestions for syntax errors in :mod:`traceback`. The
+keyword typo suggestion mechanism would incorrectly suggest replacements when
+the extracted source code was incomplete rather than containing an actual typo.
+Patch by Pablo Galindo.
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