Moved to_pt_style function to pt_utils.py and added unit tests for it

Also:
- Cache prompt-toolkit completion menu styles for efficiency
- Fixed color check bug related to default terminal style

Author: tleonhardt

cmd2/cmd2.py

@@ -192,6 +192,7 @@ def __init__(self, msg: str = "") -> None:
     Cmd2History,
     Cmd2Lexer,
     pt_filter_style,
+    to_pt_style,
 )
 from .utils import (
     Settable,
@@ -523,6 +524,10 @@ def __init__(
         self._persistent_history_length = persistent_history_length
         self._initialize_history(persistent_history_file)
 
+        # Cache for prompt_toolkit completion menu styles
+        self._cached_pt_style: PtStyle | None = None
+        self._cached_pt_style_params: tuple[Style | None, Style | None] | None = None
+
         # Create the main PromptSession
         self.bottom_toolbar = bottom_toolbar
         self.main_session = self._create_main_session(auto_suggest, completekey)
@@ -718,44 +723,28 @@ def _should_continue_multiline(self) -> bool:
 
     def _get_pt_style(self) -> "PtStyle":
         """Return the prompt_toolkit style for the completion menu."""
+        theme = ru.get_theme()
+        rich_item_style = theme.styles.get(Cmd2Style.COMPLETION_MENU_ITEM)
+        rich_meta_style = theme.styles.get(Cmd2Style.COMPLETION_MENU_META)
 
-        def 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:
-                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:
-                c = rich_style.bgcolor.get_truecolor()
-                parts.append(f"bg:#{c.red:02x}{c.green:02x}{c.blue:02x}")
-            else:
-                parts.append("bg:default")
-
-            if rich_style.bold is not None:
-                parts.append("bold" if rich_style.bold else "nobold")
-            if rich_style.italic is not None:
-                parts.append("italic" if rich_style.italic else "noitalic")
-            if rich_style.underline is not None:
-                parts.append("underline" if rich_style.underline else "nounderline")
-            return " ".join(parts)
+        current_params = (rich_item_style, rich_meta_style)
+        if self._cached_pt_style is not None and self._cached_pt_style_params == current_params:
+            return self._cached_pt_style
 
-        theme = ru.get_theme()
-        item_style = to_pt_style(theme.styles.get(Cmd2Style.COMPLETION_MENU_ITEM))
-        meta_style = to_pt_style(theme.styles.get(Cmd2Style.COMPLETION_MENU_META))
+        item_style = to_pt_style(rich_item_style)
+        meta_style = to_pt_style(rich_meta_style)
 
-        return PtStyle.from_dict(
+        self._cached_pt_style_params = current_params
+        self._cached_pt_style = PtStyle.from_dict(
             {
                 "completion-menu.completion.current": item_style,
                 "completion-menu.meta.completion.current": meta_style,
                 "completion-menu.multi-column-meta": meta_style,
             }
         )
 
+        return self._cached_pt_style
+
     def _create_main_session(self, auto_suggest: bool, completekey: str) -> PromptSession[str]:
         """Create and return the main PromptSession for the application.
 

cmd2/pt_utils.py

@@ -20,6 +20,7 @@
 from prompt_toolkit.formatted_text import ANSI
 from prompt_toolkit.history import History
 from prompt_toolkit.lexers import Lexer
+from rich.style import Style
 
 from . import (
     constants,
@@ -50,6 +51,32 @@ 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:
+    """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")
+
+    if rich_style.bold is not None:
+        parts.append("bold" if rich_style.bold else "nobold")
+    if rich_style.italic is not None:
+        parts.append("italic" if rich_style.italic else "noitalic")
+    if rich_style.underline is not None:
+        parts.append("underline" if rich_style.underline else "nounderline")
+    return " ".join(parts)
+
+
 class Cmd2Completer(Completer):
     """Completer that delegates to cmd2's completion logic."""
 

tests/test_pt_utils.py

@@ -624,3 +624,76 @@ def test_clear(self):
 
         history.clear()
         assert not history.get_strings()
+
+
+class TestToPtStyle:
+    def test_to_pt_style_none(self):
+        assert pt_utils.to_pt_style(None) == ""
+
+    def test_to_pt_style_color(self):
+        from rich.style import Style
+
+        style = Style(color="#123456")
+        pt_style = pt_utils.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):
+        from rich.style import Style
+
+        style = Style(bgcolor="#654321")
+        pt_style = pt_utils.to_pt_style(style)
+        assert "fg:default" in pt_style
+        assert "bg:#654321" in pt_style
+
+    def test_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)
+        assert "fg:default" in pt_style
+        assert "bg:default" in pt_style
+
+    def test_to_pt_style_bold(self):
+        from rich.style import Style
+
+        style = Style(bold=True)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "bold" in pt_style
+        assert "nobold" not in pt_style
+
+    def test_to_pt_style_nobold(self):
+        from rich.style import Style
+
+        style = Style(bold=False)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "nobold" in pt_style
+
+    def test_to_pt_style_italic(self):
+        from rich.style import Style
+
+        style = Style(italic=True)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "italic" in pt_style
+
+    def test_to_pt_style_noitalic(self):
+        from rich.style import Style
+
+        style = Style(italic=False)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "noitalic" in pt_style
+
+    def test_to_pt_style_underline(self):
+        from rich.style import Style
+
+        style = Style(underline=True)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "underline" in pt_style
+
+    def test_to_pt_style_nounderline(self):
+        from rich.style import Style
+
+        style = Style(underline=False)
+        pt_style = pt_utils.to_pt_style(style)
+        assert "nounderline" in pt_style