Added rich_to_pt_color conversion helper function

Created a new converter function to safely extract the correct string representation for prompt-toolkit:

- For `ColorSystem.STANDARD` colors (0-15), it maps directly to `prompt-toolkit`'s `ansicolor` names (e.g. `ansired`, `ansibrightred`). This ensures that `prompt-toolkit` delegates to the terminal's theme for the basic 16 colors.
- For `ColorSystem.EIGHT_BIT` and `ColorSystem.TRUECOLOR`, it falls back to parsing the RGB hex code (e.g., `#ff0000`), which `prompt-toolkit` supports natively.

Also:
- Renamed `to_pt_style` to `rich_to_pt_style` to make its intent more obvious
- Added tests for the new `rich_to_pt_color` conversion function

Author: tleonhardt

cmd2/cmd2.py

@@ -192,7 +192,7 @@ def __init__(self, msg: str = "") -> None:
     Cmd2History,
     Cmd2Lexer,
     pt_filter_style,
-    to_pt_style,
+    rich_to_pt_style,
 )
 from .utils import (
     Settable,
@@ -731,8 +731,8 @@ def _get_pt_style(self) -> "PtStyle":
         if self._cached_pt_style is not None and self._cached_pt_style_params == current_params:
             return self._cached_pt_style
 
-        item_style = to_pt_style(rich_item_style)
-        meta_style = to_pt_style(rich_meta_style)
+        item_style = rich_to_pt_style(rich_item_style)
+        meta_style = rich_to_pt_style(rich_meta_style)
 
         self._cached_pt_style_params = current_params
         self._cached_pt_style = PtStyle.from_dict(

cmd2/pt_utils.py

@@ -30,6 +30,8 @@
 from . import string_utils as su
 
 if TYPE_CHECKING:  # pragma: no cover
+    from rich.color import Color
+
     from .cmd2 import Cmd
 
 
@@ -51,22 +53,51 @@ def pt_filter_style(text: str | ANSI) -> str | ANSI:
     return text if isinstance(text, ANSI) else ANSI(text)
 
 
-def to_pt_style(rich_style: Style | None) -> str:
+def rich_to_pt_color(color: "Color | None") -> str:
+    """Convert a rich Color object to a prompt_toolkit color string."""
+    if not color or color.is_default:
+        return "default"
+
+    # Use prompt_toolkit's 16 standard ansi color names if applicable.
+    # This prevents overriding terminal themes with absolute RGB values.
+    if color.number is not None and 0 <= color.number <= 15:
+        # prompt_toolkit accepts these standard names directly
+        ansi_names = [
+            "ansiblack",
+            "ansired",
+            "ansigreen",
+            "ansiyellow",
+            "ansiblue",
+            "ansimagenta",
+            "ansicyan",
+            "ansiwhite",
+            "ansibrightblack",
+            "ansibrightred",
+            "ansibrightgreen",
+            "ansibrightyellow",
+            "ansibrightblue",
+            "ansibrightmagenta",
+            "ansibrightcyan",
+            "ansibrightwhite",
+        ]
+        return ansi_names[color.number]
+
+    # For 8-bit and truecolor, we fallback to hex RGB strings which prompt-toolkit supports natively
+    c = color.get_truecolor()
+    return f"#{c.red:02x}{c.green:02x}{c.blue:02x}"
+
+
+def rich_to_pt_style(rich_style: Style | None) -> str:
     """Convert a rich Style object to a prompt_toolkit style string."""
     if not rich_style:
         return ""
     parts = ["noreverse"]
-    if rich_style.color and not rich_style.color.is_default:
-        c = rich_style.color.get_truecolor()
-        parts.append(f"fg:#{c.red:02x}{c.green:02x}{c.blue:02x}")
-    else:
-        parts.append("fg:default")
-
-    if rich_style.bgcolor and not rich_style.bgcolor.is_default:
-        c = rich_style.bgcolor.get_truecolor()
-        parts.append(f"bg:#{c.red:02x}{c.green:02x}{c.blue:02x}")
-    else:
-        parts.append("bg:default")
+
+    fg_color = rich_to_pt_color(rich_style.color)
+    parts.append(f"fg:{fg_color}")
+
+    bg_color = rich_to_pt_color(rich_style.bgcolor)
+    parts.append(f"bg:{bg_color}")
 
     if rich_style.bold is not None:
         parts.append("bold" if rich_style.bold else "nobold")

tests/test_cmd2.py

@@ -1922,7 +1922,13 @@ def test_get_pt_style_caching(base_app) -> None:
         attrs = style3.class_names_and_attrs
         found = False
         for classes, attr in attrs:
-            if "completion-menu.completion.current" in classes and attr.color in ("800000", "darkred", "ff0000", "#800000"):
+            if "completion-menu.completion.current" in classes and attr.color in (
+                "800000",
+                "darkred",
+                "ff0000",
+                "#800000",
+                "ansired",
+            ):
                 found = True
                 break
         assert found, "Color change not found in cached style"

tests/test_pt_utils.py

@@ -602,74 +602,110 @@ def test_clear(self):
         assert not history.get_strings()
 
 
-class TestToPtStyle:
-    def test_to_pt_style_none(self):
-        assert pt_utils.to_pt_style(None) == ""
+class TestRichToPtColor:
+    def test_rich_to_pt_color_none(self):
+        assert pt_utils.rich_to_pt_color(None) == "default"
 
-    def test_to_pt_style_color(self):
+    def test_rich_to_pt_color_default(self):
+        from rich.color import Color
+
+        c = Color.parse("default")
+        assert pt_utils.rich_to_pt_color(c) == "default"
+
+    def test_rich_to_pt_color_standard(self):
+        from rich.color import Color
+
+        c = Color.parse("red")
+        assert pt_utils.rich_to_pt_color(c) == "ansired"
+        c = Color.parse("bright_red")
+        assert pt_utils.rich_to_pt_color(c) == "ansibrightred"
+        # Test a standard color initialized by number
+        c = Color.from_ansi(2)
+        assert pt_utils.rich_to_pt_color(c) == "ansigreen"
+
+    def test_rich_to_pt_color_eight_bit(self):
+        from rich.color import Color
+
+        # 155 is an 8-bit color
+        c = Color.from_ansi(155)
+        # Should convert to truecolor hex equivalent #afff5f
+        assert pt_utils.rich_to_pt_color(c) == "#afff5f"
+
+    def test_rich_to_pt_color_truecolor(self):
+        from rich.color import Color
+
+        c = Color.parse("#123456")
+        assert pt_utils.rich_to_pt_color(c) == "#123456"
+
+
+class TestRichToPtStyle:
+    def test_rich_to_pt_style_none(self):
+        assert pt_utils.rich_to_pt_style(None) == ""
+
+    def test_rich_to_pt_style_color(self):
         from rich.style import Style
 
         style = Style(color="#123456")
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "fg:#123456" in pt_style
         assert "bg:default" in pt_style
         assert "noreverse" in pt_style
 
-    def test_to_pt_style_bgcolor(self):
+    def test_rich_to_pt_style_bgcolor(self):
         from rich.style import Style
 
         style = Style(bgcolor="#654321")
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "fg:default" in pt_style
         assert "bg:#654321" in pt_style
 
-    def test_to_pt_style_default_color(self):
+    def test_rich_to_pt_style_default_color(self):
         from rich.style import Style
 
         style = Style(color="default", bgcolor="default")
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "fg:default" in pt_style
         assert "bg:default" in pt_style
 
-    def test_to_pt_style_bold(self):
+    def test_rich_to_pt_style_bold(self):
         from rich.style import Style
 
         style = Style(bold=True)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "bold" in pt_style
         assert "nobold" not in pt_style
 
-    def test_to_pt_style_nobold(self):
+    def test_rich_to_pt_style_nobold(self):
         from rich.style import Style
 
         style = Style(bold=False)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "nobold" in pt_style
 
-    def test_to_pt_style_italic(self):
+    def test_rich_to_pt_style_italic(self):
         from rich.style import Style
 
         style = Style(italic=True)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "italic" in pt_style
 
-    def test_to_pt_style_noitalic(self):
+    def test_rich_to_pt_style_noitalic(self):
         from rich.style import Style
 
         style = Style(italic=False)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "noitalic" in pt_style
 
-    def test_to_pt_style_underline(self):
+    def test_rich_to_pt_style_underline(self):
         from rich.style import Style
 
         style = Style(underline=True)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "underline" in pt_style
 
-    def test_to_pt_style_nounderline(self):
+    def test_rich_to_pt_style_nounderline(self):
         from rich.style import Style
 
         style = Style(underline=False)
-        pt_style = pt_utils.to_pt_style(style)
+        pt_style = pt_utils.rich_to_pt_style(style)
         assert "nounderline" in pt_style