No longer overwriting sys.stderr.

CHANGELOG.md

@@ -6,6 +6,14 @@
       `Cmd._build_parser()`. This code had previously been restored to support backward
       compatibility in `cmd2` 2.0 family.
 
+    - In an effort be consistent with the purpose of `self.stdout` and our own documentation, the
+      following changes were made.
+        - No longer redirecting `sys.stdout`.
+        - No longer capturing pyscript output written to `sys.stdout`.
+            - To assist with this change, calling `print()` within a pyscript now writes to
+              `self.stdout`. Calling `self.poutput()` within a pyscript is still preferred, but that
+              may not always be possible.
+
 - Enhancements
 
     - Simplified the process to set a custom parser for `cmd2's` built-in commands. See

cmd2/cmd2.py

@@ -2856,7 +2856,7 @@ def _redirect_output(self, statement: Statement) -> utils.RedirectionSavedState:
 
         # Initialize the redirection saved state
         redir_saved_state = utils.RedirectionSavedState(
-            cast(TextIO, self.stdout), sys.stdout, self._cur_pipe_proc_reader, self._redirecting
+            cast(TextIO, self.stdout), self._cur_pipe_proc_reader, self._redirecting
         )
 
         # The ProcReader for this command
@@ -2912,7 +2912,7 @@ def _redirect_output(self, statement: Statement) -> utils.RedirectionSavedState:
                 raise RedirectionError(f'Pipe process exited with code {proc.returncode} before command could run')
             redir_saved_state.redirecting = True  # type: ignore[unreachable]
             cmd_pipe_proc_reader = utils.ProcReader(proc, cast(TextIO, self.stdout), sys.stderr)
-            sys.stdout = self.stdout = new_stdout
+            self.stdout = new_stdout
 
         elif statement.output:
             if statement.output_to:
@@ -2926,7 +2926,7 @@ def _redirect_output(self, statement: Statement) -> utils.RedirectionSavedState:
                     raise RedirectionError('Failed to redirect output') from ex
 
                 redir_saved_state.redirecting = True
-                sys.stdout = self.stdout = new_stdout
+                self.stdout = new_stdout
 
             else:
                 # Redirecting to a paste buffer
@@ -2944,7 +2944,7 @@ def _redirect_output(self, statement: Statement) -> utils.RedirectionSavedState:
                 # create a temporary file to store output
                 new_stdout = cast(TextIO, tempfile.TemporaryFile(mode="w+"))  # noqa: SIM115
                 redir_saved_state.redirecting = True
-                sys.stdout = self.stdout = new_stdout
+                self.stdout = new_stdout
 
                 if statement.output == constants.REDIRECTION_APPEND:
                     self.stdout.write(current_paste_buffer)
@@ -2972,9 +2972,8 @@ def _restore_output(self, statement: Statement, saved_redir_state: utils.Redirec
                 # Close the file or pipe that stdout was redirected to
                 self.stdout.close()
 
-            # Restore the stdout values
+            # Restore self.stdout
             self.stdout = cast(TextIO, saved_redir_state.saved_self_stdout)
-            sys.stdout = cast(TextIO, saved_redir_state.saved_sys_stdout)
 
             # Check if we need to wait for the process being piped to
             if self._cur_pipe_proc_reader is not None:
@@ -4449,22 +4448,13 @@ def _set_up_py_shell_env(self, interp: InteractiveConsole) -> _SavedCmd2Env:
         # Set up sys module for the Python console
         self._reset_py_display()
 
-        cmd2_env.sys_stdout = sys.stdout
-        sys.stdout = self.stdout  # type: ignore[assignment]
-
-        cmd2_env.sys_stdin = sys.stdin
-        sys.stdin = self.stdin  # type: ignore[assignment]
-
         return cmd2_env
 
     def _restore_cmd2_env(self, cmd2_env: _SavedCmd2Env) -> None:
         """Restore cmd2 environment after exiting an interactive Python shell.
 
         :param cmd2_env: the environment settings to restore
         """
-        sys.stdout = cmd2_env.sys_stdout  # type: ignore[assignment]
-        sys.stdin = cmd2_env.sys_stdin  # type: ignore[assignment]
-
         # Set up readline for cmd2
         if rl_type != RlType.NONE:
             # Save py's history
@@ -4539,6 +4529,11 @@ def py_quit() -> None:
             if self.self_in_py:
                 local_vars['self'] = self
 
+            # Since poutput() may not be available in a pyscript, like in the case when self_in_py is False,
+            # provide a version of print() which writes to self.stdout. This way, print's output can be
+            # captured and redirected.
+            local_vars['print'] = functools.partial(print, file=self.stdout)
+
             # Handle case where we were called by do_run_pyscript()
             if pyscript is not None:
                 # Read the script file

cmd2/py_bridge.py

@@ -4,10 +4,7 @@
 """
 
 import sys
-from contextlib import (
-    redirect_stderr,
-    redirect_stdout,
-)
+from contextlib import redirect_stderr
 from typing import (
     IO,
     TYPE_CHECKING,
@@ -19,9 +16,7 @@
     cast,
 )
 
-from .utils import (  # namedtuple_with_defaults,
-    StdSim,
-)
+from .utils import StdSim
 
 if TYPE_CHECKING:  # pragma: no cover
     import cmd2
@@ -113,7 +108,7 @@ def __call__(self, command: str, *, echo: Optional[bool] = None) -> CommandResul
         if echo is None:
             echo = self.cmd_echo
 
-        # This will be used to capture _cmd2_app.stdout and sys.stdout
+        # This will be used to capture _cmd2_app.stdout
         copy_cmd_stdout = StdSim(cast(Union[TextIO, StdSim], self._cmd2_app.stdout), echo=echo)
 
         # Pause the storing of stdout until onecmd_plus_hooks enables it
@@ -127,7 +122,7 @@ def __call__(self, command: str, *, echo: Optional[bool] = None) -> CommandResul
         stop = False
         try:
             self._cmd2_app.stdout = cast(TextIO, copy_cmd_stdout)
-            with redirect_stdout(cast(IO[str], copy_cmd_stdout)), redirect_stderr(cast(IO[str], copy_stderr)):
+            with redirect_stderr(cast(IO[str], copy_stderr)):
                 stop = self._cmd2_app.onecmd_plus_hooks(
                     command,
                     add_to_history=self._add_to_history,

cmd2/utils.py

@@ -13,10 +13,22 @@
 import sys
 import threading
 import unicodedata
-from collections.abc import Callable, Iterable
+from collections.abc import (
+    Callable,
+    Iterable,
+)
 from difflib import SequenceMatcher
 from enum import Enum
-from typing import TYPE_CHECKING, Any, Optional, TextIO, TypeVar, Union, cast, get_type_hints
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Optional,
+    TextIO,
+    TypeVar,
+    Union,
+    cast,
+    get_type_hints,
+)
 
 from . import constants
 from .argparse_custom import ChoicesProviderFunc, CompleterFunc
@@ -683,23 +695,20 @@ class RedirectionSavedState:
     def __init__(
         self,
         self_stdout: Union[StdSim, TextIO],
-        sys_stdout: Union[StdSim, TextIO],
         pipe_proc_reader: Optional[ProcReader],
         saved_redirecting: bool,
     ) -> None:
         """RedirectionSavedState initializer.
 
         :param self_stdout: saved value of Cmd.stdout
-        :param sys_stdout: saved value of sys.stdout
         :param pipe_proc_reader: saved value of Cmd._cur_pipe_proc_reader
         :param saved_redirecting: saved value of Cmd._redirecting.
         """
         # Tells if command is redirecting
         self.redirecting = False
 
-        # Used to restore values after redirection ends
+        # Used to restore self.stdout after redirection ends
         self.saved_self_stdout = self_stdout
-        self.saved_sys_stdout = sys_stdout
 
         # Used to restore values after command ends regardless of whether the command redirected
         self.saved_pipe_proc_reader = pipe_proc_reader

docs/features/settings.md

@@ -61,7 +61,7 @@ be run by the [edit](./builtin_commands.md#edit) command.
 
 ### feedback_to_output
 
-Controls whether feedback generated with the `cmd2.Cmd.pfeedback` method is sent to `sys.stdout` or
+Controls whether feedback generated with the `cmd2.Cmd.pfeedback` method is sent to `self.stdout` or
 `sys.stderr`. If `False` the output will be sent to `sys.stderr`
 
 If `True` the output is sent to `stdout` (which is often the screen but may be

tests/test_run_pyscript.py

@@ -9,6 +9,7 @@
 import pytest
 
 from cmd2 import (
+    cmd2,
     plugin,
     utils,
 )
@@ -18,14 +19,6 @@
     run_cmd,
 )
 
-HOOK_OUTPUT = "TEST_OUTPUT"
-
-
-def cmdfinalization_hook(data: plugin.CommandFinalizationData) -> plugin.CommandFinalizationData:
-    """A cmdfinalization_hook hook which requests application exit"""
-    print(HOOK_OUTPUT)
-    return data
-
 
 def test_run_pyscript(base_app, request) -> None:
     test_dir = os.path.dirname(request.module.__file__)
@@ -133,11 +126,23 @@ def test_run_pyscript_dir(base_app, request) -> None:
     assert out[0] == "['cmd_echo']"
 
 
-def test_run_pyscript_stdout_capture(base_app, request) -> None:
-    base_app.register_cmdfinalization_hook(cmdfinalization_hook)
+def test_run_pyscript_stdout_capture(request) -> None:
+    class HookApp(cmd2.Cmd):
+        HOOK_OUTPUT = "TEST_OUTPUT"
+
+        def __init__(self) -> None:
+            super().__init__()
+            self.register_cmdfinalization_hook(self.cmdfinalization_hook)
+
+        def cmdfinalization_hook(self, data: plugin.CommandFinalizationData) -> plugin.CommandFinalizationData:
+            """A cmdfinalization_hook prints output."""
+            self.poutput(self.HOOK_OUTPUT)
+            return data
+
+    hook_app = HookApp()
     test_dir = os.path.dirname(request.module.__file__)
     python_script = os.path.join(test_dir, 'pyscript', 'stdout_capture.py')
-    out, err = run_cmd(base_app, f'run_pyscript {python_script} {HOOK_OUTPUT}')
+    out, err = run_cmd(hook_app, f'run_pyscript {python_script} {hook_app.HOOK_OUTPUT}')
 
     assert out[0] == "PASSED"
     assert out[1] == "PASSED"