bpo-42877: add the 'compact' param to TracebackException's __init__ (#24179)

Use it to reduce the time and memory taken up by several of traceback's module-level functions.

1 files changed, 40 insertions, 0 deletions

diff --git a/Lib/test/test_traceback.py b/Lib/test/test_traceback.py
index 07555a0411a..33bdda02666 100644
--- a/Lib/test/test_traceback.py
+++ b/Lib/test/test_traceback.py
@@ -1173,6 +1173,46 @@ class TestTracebackException(unittest.TestCase):
         self.assertIn(
             "RecursionError: maximum recursion depth exceeded", res[-1])
 
+    def test_compact_with_cause(self):
+        try:
+            try:
+                1/0
+            finally:
+                cause = Exception("cause")
+                raise Exception("uh oh") from cause
+        except Exception:
+            exc_info = sys.exc_info()
+            exc = traceback.TracebackException(*exc_info, compact=True)
+            expected_stack = traceback.StackSummary.extract(
+                traceback.walk_tb(exc_info[2]))
+        exc_cause = traceback.TracebackException(Exception, cause, None)
+        self.assertEqual(exc_cause, exc.__cause__)
+        self.assertEqual(None, exc.__context__)
+        self.assertEqual(True, exc.__suppress_context__)
+        self.assertEqual(expected_stack, exc.stack)
+        self.assertEqual(exc_info[0], exc.exc_type)
+        self.assertEqual(str(exc_info[1]), str(exc))
+
+    def test_compact_no_cause(self):
+        try:
+            try:
+                1/0
+            finally:
+                exc_info_context = sys.exc_info()
+                exc_context = traceback.TracebackException(*exc_info_context)
+                raise Exception("uh oh")
+        except Exception:
+            exc_info = sys.exc_info()
+            exc = traceback.TracebackException(*exc_info, compact=True)
+            expected_stack = traceback.StackSummary.extract(
+                traceback.walk_tb(exc_info[2]))
+        self.assertEqual(None, exc.__cause__)
+        self.assertEqual(exc_context, exc.__context__)
+        self.assertEqual(False, exc.__suppress_context__)
+        self.assertEqual(expected_stack, exc.stack)
+        self.assertEqual(exc_info[0], exc.exc_type)
+        self.assertEqual(str(exc_info[1]), str(exc))
+
     def test_no_refs_to_exception_and_traceback_objects(self):
         try:
             1/0