bpo-43318: Fix a bug where pdb does not always echo cleared breakpoints (GH-24646)

Lib/pdb.py

@@ -893,7 +893,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
             except ValueError:
                 err = "Invalid line number (%s)" % arg
             else:
-                bplist = self.get_breaks(filename, lineno)
+                bplist = self.get_breaks(filename, lineno)[:]
                 err = self.clear_break(filename, lineno)
             if err:
                 self.error(err)

Lib/test/test_pdb.py

@@ -1322,6 +1322,35 @@ def test_pdb_issue_20766():
     pdb 2: <built-in function default_int_handler>
     """
 
+def test_pdb_issue_43318():
+    """echo breakpoints cleared with filename:lineno
+
+    >>> def test_function():
+    ...     import pdb; pdb.Pdb(nosigint=True, readrc=False).set_trace()
+    ...     print(1)
+    ...     print(2)
+    ...     print(3)
+    ...     print(4)
+    >>> reset_Breakpoint()
+    >>> with PdbTestInput([  # doctest: +NORMALIZE_WHITESPACE
+    ...     'break 3',
+    ...     'clear <doctest test.test_pdb.test_pdb_issue_43318[0]>:3',
+    ...     'continue'
+    ... ]):
+    ...     test_function()
+    > <doctest test.test_pdb.test_pdb_issue_43318[0]>(3)test_function()
+    -> print(1)
+    (Pdb) break 3
+    Breakpoint 1 at <doctest test.test_pdb.test_pdb_issue_43318[0]>:3
+    (Pdb) clear <doctest test.test_pdb.test_pdb_issue_43318[0]>:3
+    Deleted breakpoint 1 at <doctest test.test_pdb.test_pdb_issue_43318[0]>:3
+    (Pdb) continue
+    1
+    2
+    3
+    4
+    """
+
 
 class PdbTestCase(unittest.TestCase):
     def tearDown(self):

Misc/NEWS.d/next/Library/2021-02-25-08-32-06.bpo-43318.bZJw6V.rst

@@ -0,0 +1 @@
+Fix a bug where :mod:`pdb` does not always echo cleared breakpoints.