From 775fd782fca77037c3f9bca6f7c528bcef669acb Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 2 Oct 2023 07:58:22 -0700
Subject: [3.12] gh-109375: Fix bug where pdb registers an alias without an
 associated command (GH-109376) (#109429)

gh-109375: Fix bug where pdb registers an alias without an associated command (GH-109376)
(cherry picked from commit 68a6f21f47e779ddd70e33cf04d170a63f077fcd)

Co-authored-by: buermarc <44375277+buermarc@users.noreply.github.com>
---
 Lib/pdb.py                                                         | 7 +++++--
 Lib/test/test_pdb.py                                               | 6 ++++++
 Misc/ACKS                                                          | 1 +
 .../next/Library/2023-09-13-17-22-44.gh-issue-109375.ijJHZ9.rst    | 1 +
 4 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-09-13-17-22-44.gh-issue-109375.ijJHZ9.rst

diff --git a/Lib/pdb.py b/Lib/pdb.py
index 6b6feac..646695c 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -1559,8 +1559,11 @@ class Pdb(bdb.Bdb, cmd.Cmd):
             for alias in keys:
                 self.message("%s = %s" % (alias, self.aliases[alias]))
             return
-        if args[0] in self.aliases and len(args) == 1:
-            self.message("%s = %s" % (args[0], self.aliases[args[0]]))
+        if len(args) == 1:
+            if args[0] in self.aliases:
+                self.message("%s = %s" % (args[0], self.aliases[args[0]]))
+            else:
+                self.error(f"Unknown alias '{args[0]}'")
         else:
             self.aliases[args[0]] = ' '.join(args[1:])
 
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
index 5793dbf..c0fb612 100644
--- a/Lib/test/test_pdb.py
+++ b/Lib/test/test_pdb.py
@@ -662,8 +662,10 @@ def test_pdb_alias_command():
     ...     o.method()
 
     >>> with PdbTestInput([  # doctest: +ELLIPSIS
+    ...     'alias pi',
     ...     'alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = {%1.__dict__[k]}")',
     ...     'alias ps pi self',
+    ...     'alias ps',
     ...     'pi o',
     ...     's',
     ...     'ps',
@@ -672,8 +674,12 @@ def test_pdb_alias_command():
     ...    test_function()
     > <doctest test.test_pdb.test_pdb_alias_command[1]>(4)test_function()
     -> o.method()
+    (Pdb) alias pi
+    *** Unknown alias 'pi'
     (Pdb) alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = {%1.__dict__[k]}")
     (Pdb) alias ps pi self
+    (Pdb) alias ps
+    ps = pi self
     (Pdb) pi o
     o.attr1 = 10
     o.attr2 = str
diff --git a/Misc/ACKS b/Misc/ACKS
index 7deef8b..5bba961 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -254,6 +254,7 @@ Curtis Bucher
 Colm Buckley
 Erik de Bueger
 Jan-Hein Bührman
+Marc Bürg
 Lars Buitinck
 Artem Bulgakov
 Dick Bulterman
diff --git a/Misc/NEWS.d/next/Library/2023-09-13-17-22-44.gh-issue-109375.ijJHZ9.rst b/Misc/NEWS.d/next/Library/2023-09-13-17-22-44.gh-issue-109375.ijJHZ9.rst
new file mode 100644
index 0000000..9b7a85d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-09-13-17-22-44.gh-issue-109375.ijJHZ9.rst
@@ -0,0 +1 @@
+The :mod:`pdb` ``alias`` command now prevents registering aliases without arguments.
-- 
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