Fixed cmd2 bypassing NO_COLOR and allow_style when setting prompt-toolkit's color depth.

Author: kmvanbrunt

CHANGELOG.md

@@ -12,6 +12,7 @@
 - Bug Fixes
     - Fixed type hinting so that methods decorated with `with_annotated` no longer trigger spurious
       mypy errors and preserve their original signature.
+    - Fixed cmd2 bypassing NO_COLOR and allow_style when setting prompt-toolkit's color depth.
 
 - Experimental features
     - `@with_annotated` now supports `frozenset[T]` collection parameters, alongside the existing

cmd2/cmd2.py

@@ -79,7 +79,6 @@
 from prompt_toolkit.input import DummyInput, create_input
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit.output import DummyOutput, create_output
-from prompt_toolkit.output.color_depth import ColorDepth
 from prompt_toolkit.patch_stdout import patch_stdout
 from prompt_toolkit.shortcuts import CompleteStyle, PromptSession, choice, set_title
 from prompt_toolkit.styles import DynamicStyle
@@ -202,6 +201,7 @@ def __init__(self, msg: str = "") -> None:
     Cmd2History,
     Cmd2Lexer,
     pt_filter_style,
+    pt_resolve_color_depth,
 )
 from .utils import (
     Settable,
@@ -778,7 +778,7 @@ def _(event: Any) -> None:  # pragma: no cover
         kwargs: dict[str, Any] = {
             "auto_suggest": AutoSuggestFromHistory() if auto_suggest else None,
             "bottom_toolbar": self.get_bottom_toolbar if enable_bottom_toolbar else None,
-            "color_depth": ColorDepth.TRUE_COLOR,
+            "color_depth": pt_resolve_color_depth(),
             "complete_style": CompleteStyle.MULTI_COLUMN,
             "complete_in_thread": complete_in_thread,
             "complete_while_typing": False,
@@ -1443,6 +1443,7 @@ def allow_style(self) -> ru.AllowStyle:
     def allow_style(self, value: ru.AllowStyle) -> None:
         """Setter property needed to support do_set when it updates allow_style."""
         ru.ALLOW_STYLE = value
+        self.main_session.color_depth = pt_resolve_color_depth()
 
     @property
     def traceback_show_locals(self) -> bool:

cmd2/pt_utils.py

@@ -1,5 +1,6 @@
 """Utilities for integrating prompt_toolkit with cmd2."""
 
+import os
 import re
 from collections.abc import (
     Callable,
@@ -21,6 +22,7 @@
 from prompt_toolkit.formatted_text import ANSI
 from prompt_toolkit.history import History
 from prompt_toolkit.lexers import Lexer
+from prompt_toolkit.output.color_depth import ColorDepth
 from rich.style import Style, StyleType
 
 from . import (
@@ -75,6 +77,13 @@ def pt_filter_style(text: str | ANSI) -> str | ANSI:
     return text if isinstance(text, ANSI) else ANSI(text)
 
 
+def pt_resolve_color_depth() -> ColorDepth:
+    """Determine the prompt-toolkit ColorDepth based on NO_COLOR and ru.ALLOW_STYLE."""
+    if "NO_COLOR" in os.environ or ru.ALLOW_STYLE == ru.AllowStyle.NEVER:
+        return ColorDepth.DEPTH_1_BIT
+    return ColorDepth.TRUE_COLOR
+
+
 @lru_cache(maxsize=256)
 def rich_to_pt_color(color: "Color | None") -> str:
     """Convert a rich Color object to a prompt_toolkit color string."""

cmd2/styles.py

@@ -72,7 +72,10 @@ class Cmd2Style(StrEnum):
     Cmd2Style.COMMAND_LINE: Style(color=Color.CYAN, bold=True),
     Cmd2Style.COMPLETION_MENU: Style(color="#000000", bgcolor="#bbbbbb"),  # prompt-toolkit default
     Cmd2Style.COMPLETION_MENU_COMPLETION: Style(),  # prompt-toolkit default
-    Cmd2Style.COMPLETION_MENU_CURRENT: Style(color=Color.GREEN, bgcolor=Color.BLACK),  # This style swaps FG and BG colors
+    # Defined with swapped FG/BG colors because prompt-toolkit applies 'reverse' by default.
+    # This yields a black-on-green highlight in color mode, while maintaining a fallback
+    # reverse-video highlight when colors are disabled (e.g. NO_COLOR=1 or allow_style=never).
+    Cmd2Style.COMPLETION_MENU_CURRENT: Style(color=Color.GREEN, bgcolor=Color.BLACK),
     Cmd2Style.COMPLETION_MENU_META: Style(color="#000000", bgcolor="#bbbbbb"),  # prompt-toolkit default
     Cmd2Style.COMPLETION_MENU_META_CURRENT: Style(color=Color.BLACK, bgcolor=Color.BRIGHT_GREEN),
     Cmd2Style.ERROR: Style(color=Color.BRIGHT_RED),

tests/test_cmd2.py

@@ -245,7 +245,9 @@ def test_set_no_settables(base_app) -> None:
     ],
 )
 @with_ansi_style(ru.AllowStyle.TERMINAL)
-def test_set_allow_style(base_app, new_val, is_valid, expected) -> None:
+def test_set_allow_style(base_app: cmd2.Cmd, new_val: str, is_valid: bool, expected: ru.AllowStyle) -> None:
+    from cmd2.pt_utils import pt_resolve_color_depth
+
     # Use the set command to alter allow_style
     out, err = run_cmd(base_app, f"set allow_style {new_val}")
     assert base_app.last_result is is_valid
@@ -255,6 +257,7 @@ def test_set_allow_style(base_app, new_val, is_valid, expected) -> None:
     if is_valid:
         assert out
         assert not err
+        assert base_app.main_session.color_depth == pt_resolve_color_depth()
 
 
 def test_set_traceback_show_locals(base_app: cmd2.Cmd) -> None:

tests/test_pt_utils.py

@@ -11,6 +11,7 @@
     ANSI,
     to_formatted_text,
 )
+from prompt_toolkit.output.color_depth import ColorDepth
 from rich.table import Table
 
 import cmd2
@@ -25,6 +26,7 @@
 from cmd2.pt_utils import (
     Cmd2Lexer,
     pt_filter_style,
+    pt_resolve_color_depth,
 )
 
 from .conftest import with_ansi_style
@@ -96,6 +98,34 @@ def test_pt_filter_style_never() -> None:
     assert result == su.strip_style(styled)
 
 
+@with_ansi_style(ru.AllowStyle.ALWAYS)
+def test_pt_resolve_color_depth_always(monkeypatch) -> None:
+    # Ensure any host NO_COLOR environment variable doesn't affect the test
+    monkeypatch.delenv("NO_COLOR", raising=False)
+    assert pt_resolve_color_depth() == ColorDepth.TRUE_COLOR
+
+
+@with_ansi_style(ru.AllowStyle.TERMINAL)
+def test_pt_resolve_color_depth_terminal(monkeypatch) -> None:
+    # Ensure any host NO_COLOR environment variable doesn't affect the test
+    monkeypatch.delenv("NO_COLOR", raising=False)
+    assert pt_resolve_color_depth() == ColorDepth.TRUE_COLOR
+
+
+@with_ansi_style(ru.AllowStyle.NEVER)
+def test_pt_resolve_color_depth_never(monkeypatch) -> None:
+    # Under NEVER, colors are suppressed regardless of NO_COLOR
+    monkeypatch.delenv("NO_COLOR", raising=False)
+    assert pt_resolve_color_depth() == ColorDepth.DEPTH_1_BIT
+
+
+@with_ansi_style(ru.AllowStyle.ALWAYS)
+def test_pt_resolve_color_depth_no_color(monkeypatch) -> None:
+    # Mock NO_COLOR=1 to ensure colors are suppressed
+    monkeypatch.setenv("NO_COLOR", "1")
+    assert pt_resolve_color_depth() == ColorDepth.DEPTH_1_BIT
+
+
 class TestCmd2Lexer:
     @with_ansi_style(ru.AllowStyle.NEVER)
     def test_lex_document_no_style(self, mock_cmd_app):