Cocoa MessageBox: don't use native message box if detailed text is set

As per the documentation: A message box displays a primary
text to alert the user to a situation, an informative text to
further explain the situation, and an optional detailed text to provide
even more data if the user requests it.

The AppKit NSAlert doesn't provide such a "detailed" section, and our
code just added this "even more data" detailed text to the primary text.

This breaks the UI when the detailed text is very long, perhaps a
complete log output with dozens or even hundreds of lines of text.

Since NSAlert doesn't provide a "details" space, fall-back to the non-
native message box if detailed text is provided.

[ChangeLog][QtWidgets][QMessageBox] On Apple platforms, the native
message box is no longer used when detailed text is set.

Pick-to: 6.5
Fixes: QTBUG-118992
Change-Id: I6f4764ceb8f8e57d641c0b0660223a9c26f5bd26
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
(cherry picked from commit 8753bb3045d020bcae33eed67a2770a4709ac7b8)

1 files changed, 7 insertions, 4 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
index b09f6bf54e..82a4c90c23 100644
--- a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
+++ b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
@@ -91,6 +91,12 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
     if (!options())
         return false;
 
+    // NSAlert doesn't have a section for detailed text
+    if (!options()->detailedText().isEmpty()) {
+        qCWarning(lcQpaDialogs, "Message box contains detailed text");
+        return false;
+    }
+
     if (Qt::mightBeRichText(options()->text()) ||
         Qt::mightBeRichText(options()->informativeText())) {
         // Let's fallback to non-native message box,
@@ -103,10 +109,7 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
     m_alert = [NSAlert new];
     m_alert.window.title = options()->windowTitle().toNSString();
 
-    QString text = toPlainText(options()->text());
-    QString details = toPlainText(options()->detailedText());
-    if (!details.isEmpty())
-        text += u"\n\n"_s + details;
+    const QString text = toPlainText(options()->text());
     m_alert.messageText = text.toNSString();
     m_alert.informativeText = toPlainText(options()->informativeText()).toNSString();