gh-123756: Disable restart command if pdb is in inline mode (#123757)

Doc/library/pdb.rst

@@ -198,7 +198,7 @@ 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)
+               nosigint=False, readrc=True, mode=None)
 
    :class:`Pdb` is the debugger class.
 
@@ -217,6 +217,13 @@ access further features, you have to do this yourself:
    The *readrc* argument defaults to true and controls whether Pdb will load
    .pdbrc files from the filesystem.
 
+   The *mode* argument specifies how the debugger was invoked.
+   It impacts the workings of some debugger commands.
+   Valid values are ``'inline'`` (used by the breakpoint() builtin),
+   ``'cli'`` (used by the command line invocation)
+   or ``None`` (for backwards compatible behaviour, as before the *mode*
+   argument was added).
+
    Example call to enable tracing with *skip*::
 
       import pdb; pdb.Pdb(skip=['django.*']).set_trace()
@@ -233,6 +240,9 @@ access further features, you have to do this yourself:
    .. versionchanged:: 3.6
       The *readrc* argument.
 
+   .. versionadded:: 3.14
+      Added the *mode* argument.
+
    .. method:: run(statement, globals=None, locals=None)
                runeval(expression, globals=None, locals=None)
                runcall(function, *args, **kwds)
@@ -675,6 +685,10 @@ can be overridden by the local file.
    History, breakpoints, actions and debugger options are preserved.
    :pdbcmd:`restart` is an alias for :pdbcmd:`run`.
 
+   .. versionchanged:: 3.14
+      :pdbcmd:`run` and :pdbcmd:`restart` commands are disabled when the
+      debugger is invoked in ``'inline'`` mode.
+
 .. pdbcommand:: q(uit)
 
    Quit from the debugger.  The program being executed is aborted.

Doc/whatsnew/3.14.rst

@@ -318,6 +318,9 @@ pdb
   :pdbcmd:`commands` are preserved across hard-coded breakpoints.
   (Contributed by Tian Gao in :gh:`121450`.)
 
+* Added a new argument ``mode`` to :class:`pdb.Pdb`. Disabled ``restart``
+  command when :mod:`pdb` is in ``inline`` mode.
+  (Contributed by Tian Gao in :gh:`123757`.)
 
 pickle
 ------

Lib/pdb.py

@@ -309,7 +309,7 @@ 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):
+                 nosigint=False, readrc=True, mode=None):
         bdb.Bdb.__init__(self, skip=skip)
         cmd.Cmd.__init__(self, completekey, stdin, stdout)
         sys.audit("pdb.Pdb")
@@ -321,6 +321,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         self.mainpyfile = ''
         self._wait_for_mainpyfile = False
         self.tb_lineno = {}
+        self.mode = mode
         # Try to load readline if it exists
         try:
             import readline
@@ -1611,6 +1612,11 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         sys.argv.  History, breakpoints, actions and debugger options
         are preserved.  "restart" is an alias for "run".
         """
+        if self.mode == 'inline':
+            self.error('run/restart command is disabled when pdb is running in inline mode.\n'
+                       'Use the command line interface to enable restarting your program\n'
+                       'e.g. "python -m pdb myscript.py"')
+            return
         if arg:
             import shlex
             argv0 = sys.argv[0:1]
@@ -2366,7 +2372,7 @@ def set_trace(*, header=None, commands=None):
     if Pdb._last_pdb_instance is not None:
         pdb = Pdb._last_pdb_instance
     else:
-        pdb = Pdb()
+        pdb = Pdb(mode='inline')
     if header is not None:
         pdb.message(header)
     pdb.set_trace(sys._getframe().f_back, commands=commands)
@@ -2481,7 +2487,7 @@ 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()
+    pdb = Pdb(mode='cli')
     pdb.rcLines.extend(opts.commands)
     while True:
         try:

Lib/test/test_pdb.py

@@ -901,6 +901,27 @@ def test_pdb_where_command():
     (Pdb) continue
     """
 
+def test_pdb_restart_command():
+    """Test restart command
+
+    >>> def test_function():
+    ...     import pdb; pdb.Pdb(nosigint=True, readrc=False, mode='inline').set_trace()
+    ...     x = 1
+
+    >>> with PdbTestInput([  # doctest: +ELLIPSIS
+    ...     'restart',
+    ...     'continue',
+    ... ]):
+    ...    test_function()
+    > <doctest test.test_pdb.test_pdb_restart_command[0]>(2)test_function()
+    -> import pdb; pdb.Pdb(nosigint=True, readrc=False, mode='inline').set_trace()
+    (Pdb) restart
+    *** run/restart command is disabled when pdb is running in inline mode.
+    Use the command line interface to enable restarting your program
+    e.g. "python -m pdb myscript.py"
+    (Pdb) continue
+    """
+
 def test_pdb_commands_with_set_trace():
     """Test that commands can be passed to Pdb.set_trace()
 

Misc/NEWS.d/next/Library/2024-09-06-01-35-11.gh-issue-123756.Ozbhke.rst

@@ -0,0 +1 @@
+Added a new argument ``mode`` to :class:`pdb.Pdb`. Only allow :mod:`pdb` from command line to use ``restart`` command.