fix(startup): raise the config-problem modal outside the constructor

showWarnings() did two separable things and one of them could not be
reached from a test. It set the status label, which is harmless, and it
raised a QMessageBox from the MainWindow constructor, which under the
offscreen platform nothing can dismiss: the constructor never returned
and the suite hung with no output, reading as an infrastructure failure
rather than a test one.

It splits in two. applyWarnings() keeps the status label and stays in
the constructor. configProblems() returns the list, and main.cpp raises
the dialog after show(), which also gives it a visible parent to sit on.

The distinction between warnings and problems is preserved exactly: a
keybinding being ignored interrupts startup, "no sync command
configured" does not.

The warning path now has its first test, using the config shape that
caused the original hang. Mutation checked by putting the modal back in
the constructor: the test times out at 124 rather than failing, which is
the behaviour this removes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/src/mainwindow.h b/src/mainwindow.h
index b41f75d..d844f1e 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -75,6 +75,18 @@ public:
     /// really registered.
     QStringList registeredActionNames() const;
 
+    /// Configuration problems worth interrupting startup for, empty when there
+    /// are none. A keybinding the user wrote and that is being ignored counts;
+    /// a notice such as "no sync command configured" does not.
+    ///
+    /// **Returned rather than shown, and that is the point.** This used to
+    /// raise a `QMessageBox` from the CONSTRUCTOR. A modal cannot be dismissed
+    /// under the offscreen platform, so `MainWindow` never finished
+    /// constructing and the whole suite hung with no output, which reads as an
+    /// infrastructure failure rather than a test one (item 84). The caller
+    /// raises the dialog after show(); a test asserts on the list.
+    QStringList configProblems() const;
+
     /// The thread currently shown in the message pane, empty when it is blank.
     ///
     /// Empty is what "the pane is blanked" means internally: a late-arriving
@@ -460,7 +472,9 @@ private:
 
     QList<HtmlBuilder::PlaceholderHelper> placeholderHelpers() const;
 
-    void showWarnings();
+    /// Puts the warning count in the status bar. Nothing modal: see
+    /// configProblems() for why the dialog is not raised here.
+    void applyWarnings();
     void showShortcutReference();
     void showAbout();