From ff84fb3f3c775f955de3355355058c2c2e65d242 Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Fri, 9 Aug 2019 17:11:32 +0200
Subject: [PATCH] bpo-21161: pdb: default: handle list comprehensions

Fixes https://bugs.python.org/issue21161.
---
 Lib/pdb.py           |  5 +++--
 Lib/test/test_pdb.py | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/Lib/pdb.py b/Lib/pdb.py
index 69fd8bd6efb0e5..16768cd697a9b3 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -362,7 +362,8 @@ def displayhook(self, obj):
     def default(self, line):
         if line[:1] == '!': line = line[1:]
         locals = self.curframe_locals
-        globals = self.curframe.f_globals
+        ns = self.curframe.f_globals.copy()
+        ns.update(locals)
         try:
             code = compile(line + '\n', '<stdin>', 'single')
             save_stdout = sys.stdout
@@ -372,7 +373,7 @@ def default(self, line):
                 sys.stdin = self.stdin
                 sys.stdout = self.stdout
                 sys.displayhook = self.displayhook
-                exec(code, globals, locals)
+                exec(code, ns, locals)
             finally:
                 sys.stdout = save_stdout
                 sys.stdin = save_stdin
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
index 646bdb16e53b9f..d14ab0e9dcf4ab 100644
--- a/Lib/test/test_pdb.py
+++ b/Lib/test/test_pdb.py
@@ -1562,6 +1562,32 @@ def test_errors_in_command(self):
             '(Pdb) ',
         ])
 
+    def test_list_comprehensions(self):
+        script = """
+            def f():
+                mylocal = "init_mylocal"  # noqa: F841
+                import pdb; pdb.Pdb(readrc=False).set_trace()
+                print("SUCCESS")
+
+            f()
+        """
+        commands = """
+            continue
+
+            p "mylocal:" + mylocal
+            ["mylocal_1:%s" % mylocal for x in range(1)]
+            mylocal = 42
+            ["mylocal_2:%s" % mylocal for x in range(1)]
+
+            continue
+        """
+        stdout, stderr = self.run_pdb_module(script, commands)
+        lines = stdout.splitlines()
+        self.assertTrue(any("['mylocal_1:init_mylocal']" in l for l in lines), stdout)
+        self.assertTrue(any("['mylocal_2:42']" in l for l in lines), stdout)
+        self.assertTrue(all("NameError" not in l for l in lines), stdout)
+        self.assertTrue(any("SUCCESS" in l for l in lines), stdout)
+
 def load_tests(*args):
     from test import test_pdb
     suites = [