[PATCH b4 1/2] tui: fix MissingStyle crash under Textual ansi themes

[PATCH b4 1/2] tui: fix MissingStyle crash under Textual ansi themes

[Konstantin Khorenko]

Resolving styles under an ansi theme (TEXTUAL_THEME=ansi-light/dark,
or one picked from the command palette) crashes:

  MissingStyle: 'transparent' is not a valid color

Textual's ansi themes resolve $panel/$surface to the CSS keyword
"transparent" and can suffix a colour with an alpha percentage; Rich
accepts neither. Reduce both to the terminal default colour in
_to_rich_color(), which fixes every consumer of resolve_styles().

Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Assisted-by: claude-sonnet-5
---
 src/b4/tui/_common.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/b4/tui/_common.py b/src/b4/tui/_common.py
index 844d980..a378dd3 100644
--- a/src/b4/tui/_common.py
+++ b/src/b4/tui/_common.py
@@ -278,9 +278,20 @@ def matches_limit(
     variable system.  Rich expects ``green``, ``bright_blue``, etc.
     Non-ansi values (hex codes, named CSS colours) pass through unchanged.
     ``ansi_default`` maps to ``default``.
+
+    Textual's ansi themes resolve ``$panel``/``$surface`` to the CSS
+    keyword ``transparent`` and can append an alpha percentage
+    (``default 50%``). Rich understands neither, and feeding one into a
+    style string raises ``MissingStyle``, so both are reduced to the
+    terminal default colour.
     """
+    parts = textual_color.rsplit(' ', 1)
+    if len(parts) == 2 and parts[1].endswith('%'):
+        textual_color = parts[0]  # drop the alpha suffix
     if textual_color.startswith('ansi_'):
         return textual_color[5:]  # strip 'ansi_' prefix
+    if textual_color == 'transparent':
+        return 'default'
     return textual_color
 
 
-- 
2.43.0

[PATCH b4 2/2] review-tui: read native_ansi_color for the trailer overlay header

[Konstantin Khorenko]

The review status overlay picks its reverse-video header style off
App.ansi_color, a tri-state that stays None until the theme is
switched at runtime, so it never reflects an ansi theme set via
TEXTUAL_THEME and the header falls back to the wrong style. Read
native_ansi_color instead, with a getattr fallback for Textual
releases that predate the property.

Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Assisted-by: claude-sonnet-5
---
 src/b4/review_tui/_review_app.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/b4/review_tui/_review_app.py b/src/b4/review_tui/_review_app.py
index e1082e9..da60455 100644
--- a/src/b4/review_tui/_review_app.py
+++ b/src/b4/review_tui/_review_app.py
@@ -924,7 +924,7 @@ from b4.review_tui._modals import (
 
             if has_content:
                 text.append('\n')
-            if self.app.ansi_color:
+            if getattr(self.app, 'native_ansi_color', self.app.ansi_color):
                 text.append(f' {header} ', style=f'bold reverse {colour}')
             else:
                 text.append(f' {header} ', style=f'bold {ts["surface"]} on {colour}')
-- 
2.43.0

Re: [PATCH b4 1/2] tui: fix MissingStyle crash under Textual ansi themes

[Konstantin Ryabitsev]

On Fri, 04 Sep 2026 16:59:50 +0200, Konstantin Khorenko wrote:
> tui: fix MissingStyle crash under Textual ansi themes

Applied, thanks!

[1/2] tui: fix MissingStyle crash under Textual ansi themes
      commit: 99687c6f54873d234b49b33322fee011682f1cc9
[2/2] review-tui: read native_ansi_color for the trailer overlay header
      commit: 7e16afe0473cf1a066dc1f5baf348d41f7911665

One thing you may want to consider as a follow-up:

There is one more Rich-invalid keyword left. On every non-ansi
theme (textual-dark, nord, gruvbox, ...) Textual generates
text-muted as 'auto 60%', so after your alpha strip it becomes
'auto', which Rich rejects the same way it rejects 'transparent':

    unable to parse 'auto' as color; 'auto' is not a valid color

It doesn't happen today, because nothing currently reads
ts['text-muted'] -- it is only consumed as the $text-muted CSS
variable, which Textual resolves itself. However, this can become a trap 
the future bug.

It can fold into the same guard:

    if textual_color in ('transparent', 'auto'):
        return 'default'

'auto' means "pick a readable foreground", so 'default' is the
closest good Rich equivalent.

Best regards,
-- 
Konstantin Ryabitsev <konstantin@linuxfoundation.org>