From f44d6ff6e0c9eeb0bb246a3dd8f99d40b7050054 Mon Sep 17 00:00:00 2001
From: Tian Gao <gaogaotiantian@hotmail.com>
Date: Tue, 14 Nov 2023 04:22:25 -0800
Subject: [PATCH] gh-110944: Make pdb completion work for alias and convenience
 vars (GH-110945)

---
 Lib/pdb.py                                    | 18 +++++++++++++++-
 Lib/test/test_pdb.py                          | 21 +++++++++++++++++++
 ...-10-16-18-41-51.gh-issue-110944.CmUKXo.rst |  1 +
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-10-16-18-41-51.gh-issue-110944.CmUKXo.rst

diff --git a/Lib/pdb.py b/Lib/pdb.py
index a4b02e010a6..ed78d749a47 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -238,7 +238,7 @@ def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
         try:
             import readline
             # remove some common file name delimiters
-            readline.set_completer_delims(' \t\n`@#$%^&*()=+[{]}\\|;:\'",<>?')
+            readline.set_completer_delims(' \t\n`@#%^&*()=+[{]}\\|;:\'",<>?')
         except ImportError:
             pass
         self.allow_kbdint = False
@@ -686,6 +686,18 @@ def set_convenience_variable(self, frame, name, value):
     # Generic completion functions.  Individual complete_foo methods can be
     # assigned below to one of these functions.
 
+    def completenames(self, text, line, begidx, endidx):
+        # Overwrite completenames() of cmd so for the command completion,
+        # if no current command matches, check for expressions as well
+        commands = super().completenames(text, line, begidx, endidx)
+        for alias in self.aliases:
+            if alias.startswith(text):
+                commands.append(alias)
+        if commands:
+            return commands
+        else:
+            return self._complete_expression(text, line, begidx, endidx)
+
     def _complete_location(self, text, line, begidx, endidx):
         # Complete a file/module/function location for break/tbreak/clear.
         if line.strip().endswith((':', ',')):
@@ -720,6 +732,10 @@ def _complete_expression(self, text, line, begidx, endidx):
         # complete builtins, and they clutter the namespace quite heavily, so we
         # leave them out.
         ns = {**self.curframe.f_globals, **self.curframe_locals}
+        if text.startswith("$"):
+            # Complete convenience variables
+            conv_vars = self.curframe.f_globals.get('__pdb_convenience_variables', {})
+            return [f"${name}" for name in conv_vars if name.startswith(text[1:])]
         if '.' in text:
             # Walk an attribute chain up to the last part, similar to what
             # rlcompleter does.  This will bail if any of the parts are not
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
index 2ec4e2ee0e0..67a4053a2ac 100644
--- a/Lib/test/test_pdb.py
+++ b/Lib/test/test_pdb.py
@@ -3289,6 +3289,27 @@ def test_basic_completion(self):
         self.assertIn(b'continue', output)
         self.assertIn(b'hello!', output)
 
+    def test_expression_completion(self):
+        script = textwrap.dedent("""
+            value = "speci"
+            import pdb; pdb.Pdb().set_trace()
+        """)
+
+        # Complete: value + 'al'
+        input = b"val\t + 'al'\n"
+        # Complete: p value + 'es'
+        input += b"p val\t + 'es'\n"
+        # Complete: $_frame
+        input += b"$_fra\t\n"
+        # Continue
+        input += b"c\n"
+
+        output = run_pty(script, input)
+
+        self.assertIn(b'special', output)
+        self.assertIn(b'species', output)
+        self.assertIn(b'$_frame', output)
+
 
 def load_tests(loader, tests, pattern):
     from test import test_pdb
diff --git a/Misc/NEWS.d/next/Library/2023-10-16-18-41-51.gh-issue-110944.CmUKXo.rst b/Misc/NEWS.d/next/Library/2023-10-16-18-41-51.gh-issue-110944.CmUKXo.rst
new file mode 100644
index 00000000000..ec9ca5a11f1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-10-16-18-41-51.gh-issue-110944.CmUKXo.rst
@@ -0,0 +1 @@
+Support alias and convenience vars for :mod:`pdb` completion