Keep spec-derived TUI text out of the Textual markup parser

Substate lines interpolated arbitrary text (acceptance-test text from the
spec, module names) into a markup string. Textual treats every unescaped
"[" as a tag opener, so a spec line such as "ZLEXCOUNT z [b + should reply
3." swallowed the timer's "[#888888]" tag, the closing "[/#888888]" had no
match, and the whole TUI crashed with MarkupError. Terminated brackets
("LPOP key [count]") were silently dropped from the display as well.
Textual's escape() does not cover unterminated brackets, so build the line
as Content and style only the timer span instead.

Also render the other widgets that show paths or spec text (progress
descriptions, module/functionality rows, test-script rows, render id,
success/error status) with markup disabled or as Content.

Author: VitjanZ

tests/test_tui_components.py

@@ -0,0 +1,88 @@
+"""Regression tests: spec-derived text with square brackets must never be parsed as Textual markup."""
+
+import asyncio
+
+from textual.widgets import Static
+
+from event_bus import EventBus
+from plain2code_state import RunState
+from tui.components import ProgressItem, SubstateLine, TUIComponents
+from tui.models import Substate
+from tui.plain2code_tui import Plain2CodeTUI
+from tui.widget_helpers import display_error_message, display_success_message, update_progress_item_substates
+
+# Exact acceptance-test text that crashed the TUI with
+# "MarkupError: closing tag '[/#888888]' does not match any open tag":
+# the unterminated "[b" swallowed the timer's opening tag.
+UNTERMINATED_BRACKET_TEXT = (
+    "Rendering acceptance test: With a=1, b=2, c=3, d=4: ZRANK z c should reply 2, "
+    'ZREVRANK z c WITHSCORE should reply [1, "3"], ZRANK z zz should reply null, '
+    "ZCOUNT z (1 3 should reply 2, and ZLEXCOUNT z [b + should reply 3."
+)
+# Terminated brackets used to be silently eaten as a markup tag ("LPOP key ").
+TERMINATED_BRACKET_TEXT = "LPOP key [count] and RPOP key [count] reply one element"
+
+
+def _make_app(run_state: RunState, event_bus: EventBus) -> Plain2CodeTUI:
+    return Plain2CodeTUI(
+        event_bus=event_bus,
+        run_state=run_state,
+        on_ready=lambda: None,
+        render_id="test-render-id",
+        unittests_script=None,
+        conformance_tests_script="run_conformance_tests.sh",
+        prepare_environment_script=None,
+        state_machine_version="0.0.0",
+        css_path="styles.css",
+    )
+
+
+def test_substate_line_keeps_bracket_text_verbatim():
+    for text in (UNTERMINATED_BRACKET_TEXT, TERMINATED_BRACKET_TEXT):
+        line = SubstateLine(text, "    ", ProgressItem.PROCESSING)._format_line()
+        assert text in line.plain
+        assert line.plain.endswith("(0s)")
+        # Only the timer carries the muted style; the text itself is unstyled.
+        assert len(line.spans) == 1
+        assert line.plain[line.spans[0].start : line.spans[0].end] == "(0s)"
+
+
+def test_substate_with_brackets_renders_without_markup_error():
+    async def scenario():
+        event_bus = EventBus()
+        run_state = RunState(spec_filename="x.plain")
+        app = _make_app(run_state, event_bus)
+        async with app.run_test() as pilot:
+            widget_id = TUIComponents.FRID_PROGRESS_CONFORMANCE_TEST.value
+            update_progress_item_substates(
+                app, widget_id, [Substate(UNTERMINATED_BRACKET_TEXT), Substate(TERMINATED_BRACKET_TEXT)]
+            )
+            await pilot.pause()
+            await pilot.pause()
+
+            lines = app.query(".substate-line-text").results(Static)
+            rendered = [str(line.content) for line in lines]
+            assert any(UNTERMINATED_BRACKET_TEXT in text for text in rendered)
+            assert any(TERMINATED_BRACKET_TEXT in text for text in rendered)
+
+    asyncio.run(scenario())
+
+
+def test_status_messages_keep_brackets():
+    async def scenario():
+        event_bus = EventBus()
+        run_state = RunState(spec_filename="x.plain")
+        app = _make_app(run_state, event_bus)
+        async with app.run_test() as pilot:
+            status = app.query_one(f"#{TUIComponents.RENDER_STATUS_WIDGET.value}", Static)
+
+            display_success_message(app, "out/[weird] path")
+            await pilot.pause()
+            assert "rendering completed!" in str(status.content)
+            assert "generated code folder: out/[weird] path" in str(status.content)
+
+            display_error_message(app, "Error: [Errno 2] No such file: run_tests.sh [b")
+            await pilot.pause()
+            assert "[Errno 2] No such file: run_tests.sh [b" in str(status.content)
+
+    asyncio.run(scenario())

tui/components.py

@@ -3,6 +3,7 @@
 
 from rich.markup import escape
 from textual.containers import Horizontal, Vertical, VerticalScroll
+from textual.content import Content
 from textual.message import Message
 from textual.timer import Timer
 from textual.widgets import Button, Static
@@ -71,7 +72,7 @@ def compose(self):
         self._footer_text_widget = Static(footer_rendering_text, classes="custom-footer-text")
         yield self._footer_text_widget
         if self.render_id:
-            yield Static(f"render id: {self.render_id} ", classes="custom-footer-render-id")
+            yield Static(f"render id: {self.render_id} ", classes="custom-footer-render-id", markup=False)
 
     def update_footer_state(self, state: Literal["rendering", "pausing", "paused", "finished"]) -> None:
         self.remove_class("footer-state-default")
@@ -201,9 +202,12 @@ def _add_second(self) -> None:
     def _format_timer(self) -> str:
         return format_duration_hms(self._seconds_elapsed)
 
-    def _format_line(self) -> str:
+    def _format_line(self) -> Content:
+        # The substate text is arbitrary (acceptance-test text from the spec, module names, ...)
+        # and may contain square brackets, so it must never go through the markup parser.
+        # Build the line as Content and style only the timer part.
         timer = self._format_timer()
-        return f"{self.indent}  └ {self.text} [#888888]({timer})[/#888888]"
+        return Content.assemble(f"{self.indent}  └ {self.text} ", (f"({timer})", "#888888"))
 
     def _refresh_timer(self) -> None:
         try:
@@ -232,7 +236,7 @@ def compose(self):
         # Main row with status and description
         with Horizontal(id=f"{self.id}-main-row", classes="progress-main-row"):
             yield Static(self._get_status_text(self.PENDING), classes=f"status {self.PENDING}")
-            yield Static(self.initial_text, classes="description")
+            yield Static(self.initial_text, classes="description", markup=False)
         # Substates container (full width, aligned to left)
         yield Vertical(id=f"{self.id}-substates", classes="substates-container")
 
@@ -367,8 +371,8 @@ def on_mount(self) -> None:
         self._refresh_content()
 
     def compose(self):
-        self.module_widget = Static(self.module_text, classes="rendering-info-row")
-        self.functionality_widget = Static(self.functionality_text, classes="rendering-info-row")
+        self.module_widget = Static(self.module_text, classes="rendering-info-row", markup=False)
+        self.functionality_widget = Static(self.functionality_text, classes="rendering-info-row", markup=False)
         yield Static("module status", classes="rendering-info-title")
         with Vertical(classes="rendering-info-box"):
             yield self.module_widget
@@ -430,9 +434,9 @@ def on_mount(self) -> None:
     def compose(self):
         yield Static("testing status", classes="test-scripts-title")
         with Vertical(classes="test-scripts-box"):
-            self.unit_widget = Static(self.unit_test_text, classes="test-script-row")
-            self.conformance_widget = Static(self.conformance_test_text, classes="test-script-row")
-            self.testing_widget = Static(self.testing_env_text, classes="test-script-row")
+            self.unit_widget = Static(self.unit_test_text, classes="test-script-row", markup=False)
+            self.conformance_widget = Static(self.conformance_test_text, classes="test-script-row", markup=False)
+            self.testing_widget = Static(self.testing_env_text, classes="test-script-row", markup=False)
             yield self.unit_widget
             yield self.conformance_widget
             yield self.testing_widget

tui/widget_helpers.py

@@ -2,6 +2,7 @@
 
 from datetime import datetime
 
+from textual.content import Content
 from textual.css.query import NoMatches
 from textual.widgets import Static
 
@@ -89,9 +90,14 @@ def display_success_message(tui, rendered_code_path: str):
         rendered_code_path: The path to the rendered code
     """
 
-    message = (
-        f"[#79FC96]✓ rendering completed![/#79FC96] [#888888](press enter to exit)[/#888888]\n"
-        f"[#888888]generated code folder: {rendered_code_path}[/#888888] "
+    # rendered_code_path is user-controlled and may contain square brackets, so build the
+    # message as Content instead of interpolating it into a markup string.
+    message = Content.assemble(
+        ("✓ rendering completed!", "#79FC96"),
+        " ",
+        ("(press enter to exit)", "#888888"),
+        "\n",
+        (f"generated code folder: {rendered_code_path} ", "#888888"),
     )
 
     widget: Static = tui.query_one(f"#{TUIComponents.RENDER_STATUS_WIDGET.value}", Static)
@@ -120,7 +126,8 @@ def transition_frid_progress(tui, from_status: str | None, to_status: str):
 def display_error_message(tui, error_message: str):
     widget: Static = tui.query_one(f"#{TUIComponents.RENDER_STATUS_WIDGET.value}", Static)
     widget.add_class("error")
-    widget.update(error_message)
+    # Error text may contain square brackets (paths, tracebacks); keep it out of the markup parser.
+    widget.update(Content(error_message))
 
 
 def display_usage_summary(tui, functionalities: int, render_time_seconds: float) -> None: