gh-113081: Highlight source code in pdb

Doc/library/pdb.rst

@@ -243,7 +243,7 @@ The ``run*`` functions and :func:`set_trace` are aliases for instantiating the
 access further features, you have to do this yourself:
 
 .. class:: Pdb(completekey='tab', stdin=None, stdout=None, skip=None, \
-               nosigint=False, readrc=True, mode=None, backend=None)
+               nosigint=False, readrc=True, mode=None, backend=None, colorize=False)
 
    :class:`Pdb` is the debugger class.
 
@@ -273,6 +273,9 @@ access further features, you have to do this yourself:
    is passed, the default backend will be used. See :func:`set_default_backend`.
    Otherwise the supported backends are ``'settrace'`` and ``'monitoring'``.
 
+   The *colorize* argument, if set to ``True``, will enable colorized output in the
+   debugger, if color is supported. This will highlight source code displayed in pdb.
+
    Example call to enable tracing with *skip*::
 
       import pdb; pdb.Pdb(skip=['django.*']).set_trace()
@@ -295,6 +298,9 @@ access further features, you have to do this yourself:
    .. versionadded:: 3.14
       Added the *backend* argument.
 
+   .. versionadded:: 3.14
+      Added the *colorize* argument.
+
    .. versionchanged:: 3.14
       Inline breakpoints like :func:`breakpoint` or :func:`pdb.set_trace` will
       always stop the program at calling frame, ignoring the *skip* pattern (if any).

Lib/pdb.py

@@ -93,6 +93,7 @@
 import traceback
 import linecache
 import _colorize
+import _pyrepl.utils
 
 from contextlib import closing
 from contextlib import contextmanager
@@ -339,7 +340,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
     _last_pdb_instance = None
 
     def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
-                 nosigint=False, readrc=True, mode=None, backend=None):
+                 nosigint=False, readrc=True, mode=None, backend=None, colorize=False):
         bdb.Bdb.__init__(self, skip=skip, backend=backend if backend else get_default_backend())
         cmd.Cmd.__init__(self, completekey, stdin, stdout)
         sys.audit("pdb.Pdb")
@@ -352,6 +353,7 @@ def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
         self._wait_for_mainpyfile = False
         self.tb_lineno = {}
         self.mode = mode
+        self.colorize = _colorize.can_colorize(file=stdout or sys.stdout) and colorize
         # Try to load readline if it exists
         try:
             import readline
@@ -1036,6 +1038,13 @@ def handle_command_def(self, line):
             return True
         return False
 
+    def _colorize_code(self, code):
+        if self.colorize:
+            colors = list(_pyrepl.utils.gen_colors(code))
+            chars, _ = _pyrepl.utils.disp_str(code, colors=colors)
+            code = "".join(chars)
+        return code
+
     # interface abstraction functions
 
     def message(self, msg, end='\n'):
@@ -2166,6 +2175,8 @@ def _print_lines(self, lines, start, breaks=(), frame=None):
                 s += '->'
             elif lineno == exc_lineno:
                 s += '>>'
+            if self.colorize:
+                line = self._colorize_code(line)
             self.message(s + '\t' + line.rstrip())
 
     def do_whatis(self, arg):
@@ -2365,8 +2376,14 @@ def print_stack_entry(self, frame_lineno, prompt_prefix=line_prefix):
             prefix = '> '
         else:
             prefix = '  '
-        self.message(prefix +
-                     self.format_stack_entry(frame_lineno, prompt_prefix))
+        stack_entry = self.format_stack_entry(frame_lineno, prompt_prefix)
+        if self.colorize:
+            lines = stack_entry.split(prompt_prefix)
+            if len(lines) > 1:
+                # We have some code to display
+                lines[1] = self._colorize_code(lines[1])
+                stack_entry = prompt_prefix.join(lines)
+        self.message(prefix + stack_entry)
 
     # Provide help
 
@@ -2604,7 +2621,7 @@ def set_trace(*, header=None, commands=None):
     if Pdb._last_pdb_instance is not None:
         pdb = Pdb._last_pdb_instance
     else:
-        pdb = Pdb(mode='inline', backend='monitoring')
+        pdb = Pdb(mode='inline', backend='monitoring', colorize=True)
     if header is not None:
         pdb.message(header)
     pdb.set_trace(sys._getframe().f_back, commands=commands)
@@ -2619,7 +2636,7 @@ async def set_trace_async(*, header=None, commands=None):
     if Pdb._last_pdb_instance is not None:
         pdb = Pdb._last_pdb_instance
     else:
-        pdb = Pdb(mode='inline', backend='monitoring')
+        pdb = Pdb(mode='inline', backend='monitoring', colorize=True)
     if header is not None:
         pdb.message(header)
     await pdb.set_trace_async(sys._getframe().f_back, commands=commands)
@@ -2633,7 +2650,7 @@ def __init__(self, sockfile, owns_sockfile=True, **kwargs):
         self._sockfile = sockfile
         self._command_name_cache = []
         self._write_failed = False
-        super().__init__(**kwargs)
+        super().__init__(colorize=False, **kwargs)
 
     @staticmethod
     def protocol_version():
@@ -3338,7 +3355,7 @@ def main():
     # modified by the script being debugged. It's a bad idea when it was
     # changed by the user from the command line. There is a "restart" command
     # which allows explicit specification of command line arguments.
-    pdb = Pdb(mode='cli', backend='monitoring')
+    pdb = Pdb(mode='cli', backend='monitoring', colorize=True)
     pdb.rcLines.extend(opts.commands)
     while True:
         try:

Lib/test/test_pdb.py

@@ -1,7 +1,9 @@
 # A test suite for pdb; not very comprehensive at the moment.
 
+import _colorize
 import doctest
 import gc
+import io
 import os
 import pdb
 import sys
@@ -4688,6 +4690,40 @@ def foo():
         self.assertIn("42", stdout)
 
 
+@unittest.skipUnless(_colorize.can_colorize(), "Test requires colorize")
+class PdbTestColorize(unittest.TestCase):
+    def setUp(self):
+        self._original_can_colorize = _colorize.can_colorize
+        # Force colorize to be enabled because we are sending data
+        # to a StringIO
+        _colorize.can_colorize = lambda *args, **kwargs: True
+
+    def tearDown(self):
+        _colorize.can_colorize = self._original_can_colorize
+
+    def test_code_display(self):
+        output = io.StringIO()
+        p = pdb.Pdb(stdout=output, colorize=True)
+        p.set_trace(commands=['ll', 'c'])
+        self.assertIn("\x1b", output.getvalue())
+
+        output = io.StringIO()
+        p = pdb.Pdb(stdout=output, colorize=False)
+        p.set_trace(commands=['ll', 'c'])
+        self.assertNotIn("\x1b", output.getvalue())
+
+        output = io.StringIO()
+        p = pdb.Pdb(stdout=output)
+        p.set_trace(commands=['ll', 'c'])
+        self.assertNotIn("\x1b", output.getvalue())
+
+    def test_stack_entry(self):
+        output = io.StringIO()
+        p = pdb.Pdb(stdout=output, colorize=True)
+        p.set_trace(commands=['w', 'c'])
+        self.assertIn("\x1b", output.getvalue())
+
+
 @support.force_not_colorized_test_class
 @support.requires_subprocess()
 class TestREPLSession(unittest.TestCase):

Misc/NEWS.d/next/Library/2025-05-03-18-48-54.gh-issue-113081.JsLJ1X.rst

@@ -0,0 +1 @@
+Highlight syntax on source code in :mod:`pdb`.