gh-120254: Add a commands argument to pdb.set_trace

Doc/library/pdb.rst

@@ -192,7 +192,7 @@ 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, commands=None)
 
    :class:`Pdb` is the debugger class.
 
@@ -211,6 +211,9 @@ 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 *commands* argument, if given, would be a list of commands to execute
+   when the debugger starts. It has similar effects to the :file:`.pdbrc` file.
+
    Example call to enable tracing with *skip*::
 
       import pdb; pdb.Pdb(skip=['django.*']).set_trace()
@@ -227,6 +230,9 @@ access further features, you have to do this yourself:
    .. versionchanged:: 3.6
       The *readrc* argument.
 
+   .. versionadded:: 3.14
+      The *commands* argument.
+
    .. method:: run(statement, globals=None, locals=None)
                runeval(expression, globals=None, locals=None)
                runcall(function, *args, **kwds)

Lib/pdb.py

@@ -307,7 +307,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
     _file_mtime_table = {}
 
     def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
-                 nosigint=False, readrc=True):
+                 nosigint=False, readrc=True, commands=None):
         bdb.Bdb.__init__(self, skip=skip)
         cmd.Cmd.__init__(self, completekey, stdin, stdout)
         sys.audit("pdb.Pdb")
@@ -346,6 +346,9 @@ def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
             except OSError:
                 pass
 
+        if commands is not None:
+            self.rcLines.extend(commands)
+
         self.commands = {} # associates a command list to breakpoint numbers
         self.commands_doprompt = {} # for each bp num, tells if the prompt
                                     # must be disp. after execing the cmd list

Lib/test/test_pdb.py

@@ -833,6 +833,18 @@ def test_pdb_where_command():
     """
 
 
+def test_pdb_commands_at_init():
+    """Test that commands can be passed to the constructor
+
+    >>> def test_function():
+    ...     x = 1
+    ...     import pdb; pdb.Pdb(nosigint=True, readrc=False, commands=['p x', 'c']).set_trace()
+
+    >>> test_function()
+    1
+    """
+
+
 # skip this test if sys.flags.no_site = True;
 # exit() isn't defined unless there's a site module.
 if not sys.flags.no_site:

Misc/NEWS.d/next/Library/2024-06-08-03-29-01.gh-issue-120254.h682ke.rst

@@ -0,0 +1 @@
+Added ``commands`` argument to :class:`pdb.Pdb` which allows user to send debugger commands in the source file.