Copy docstrings to wrapped pdb methods

Co-authored-by: Bruno Oliveira <bruno@pytest.org>
Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

changelog/12946.bugfix.rst

@@ -0,0 +1 @@
+Fixed missing help for :mod:`pdb` commands wrapped by pytest -- by :user:`adamchainz`.

src/_pytest/debugging.py

@@ -159,6 +159,9 @@ def do_debug(self, arg):
                 cls._recursive_debug -= 1
                 return ret
 
+            if hasattr(pdb_cls, "do_debug"):
+                do_debug.__doc__ = pdb_cls.do_debug.__doc__
+
             def do_continue(self, arg):
                 ret = super().do_continue(arg)
                 if cls._recursive_debug == 0:
@@ -185,22 +188,27 @@ def do_continue(self, arg):
                 self._continued = True
                 return ret
 
+            if hasattr(pdb_cls, "do_continue"):
+                do_continue.__doc__ = pdb_cls.do_continue.__doc__
+
             do_c = do_cont = do_continue
 
             def do_quit(self, arg):
-                """Raise Exit outcome when quit command is used in pdb.
-
-                This is a bit of a hack - it would be better if BdbQuit
-                could be handled, but this would require to wrap the
-                whole pytest run, and adjust the report etc.
-                """
+                # Raise Exit outcome when quit command is used in pdb.
+                #
+                # This is a bit of a hack - it would be better if BdbQuit
+                # could be handled, but this would require to wrap the
+                # whole pytest run, and adjust the report etc.
                 ret = super().do_quit(arg)
 
                 if cls._recursive_debug == 0:
                     outcomes.exit("Quitting debugger")
 
                 return ret
 
+            if hasattr(pdb_cls, "do_quit"):
+                do_quit.__doc__ = pdb_cls.do_quit.__doc__
+
             do_q = do_quit
             do_exit = do_quit
 

testing/test_debugging.py

@@ -52,6 +52,16 @@ def reset(self):
         def interaction(self, *args):
             called.append("interaction")
 
+        # Methods which we copy docstrings to.
+        def do_debug(self, *args):  # pragma: no cover
+            pass
+
+        def do_continue(self, *args):  # pragma: no cover
+            pass
+
+        def do_quit(self, *args):  # pragma: no cover
+            pass
+
     _pytest._CustomPdb = _CustomPdb  # type: ignore
     return called
 
@@ -75,6 +85,16 @@ def set_trace(self, frame):
             print("**CustomDebugger**")
             called.append("set_trace")
 
+        # Methods which we copy docstrings to.
+        def do_debug(self, *args):  # pragma: no cover
+            pass
+
+        def do_continue(self, *args):  # pragma: no cover
+            pass
+
+        def do_quit(self, *args):  # pragma: no cover
+            pass
+
     _pytest._CustomDebugger = _CustomDebugger  # type: ignore
     yield called
     del _pytest._CustomDebugger  # type: ignore
@@ -965,6 +985,34 @@ def test_1():
         child.sendeof()
         self.flush(child)
 
+    def test_pdb_wrapped_commands_docstrings(self, pytester: Pytester) -> None:
+        p1 = pytester.makepyfile(
+            """
+            def test_1():
+                assert False
+            """
+        )
+
+        child = pytester.spawn_pytest(f"--pdb {p1}")
+        child.expect("Pdb")
+
+        # Verify no undocumented commands
+        child.sendline("help")
+        child.expect("Documented commands")
+        assert "Undocumented commands" not in child.before.decode()
+
+        child.sendline("help continue")
+        child.expect("Continue execution")
+        child.expect("Pdb")
+
+        child.sendline("help debug")
+        child.expect("Enter a recursive debugger")
+        child.expect("Pdb")
+
+        child.sendline("c")
+        child.sendeof()
+        self.flush(child)
+
 
 class TestDebuggingBreakpoints:
     @pytest.mark.parametrize("arg", ["--pdb", ""])
@@ -1288,6 +1336,16 @@ def set_trace(self, *args):
 
                 def runcall(self, *args, **kwds):
                     print("runcall_called", args, kwds)
+
+                # Methods which we copy the docstring over.
+                def do_debug(self, *args):
+                    pass
+
+                def do_continue(self, *args):
+                    pass
+
+                def do_quit(self, *args):
+                    pass
         """,
     )
     result = pytester.runpytest(
@@ -1354,6 +1412,16 @@ def __init__(self, *args, **kwargs):
 
             def set_trace(self, *args):
                 print("set_trace_called", args)
+
+            # Methods which we copy the docstring over.
+            def do_debug(self, *args):
+                pass
+
+            def do_continue(self, *args):
+                pass
+
+            def do_quit(self, *args):
+                pass
         """,
     )
     result = pytester.runpytest(str(p1), "--pdbcls=mypdb:MyPdb", syspathinsert=True)