4 files changed, 38 insertions, 20 deletions

diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 6dbba8b433..b4e2b47c03 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -971,6 +971,11 @@ QString QWindow::filePath() const
 
     The window icon might be used by the windowing system for example to
     decorate the window, and/or in the task switcher.
+
+    \note On \macos, the window title bar icon is meant for windows representing
+    documents, and will only show up if a file path is also set.
+
+    \sa setFilePath()
 */
 void QWindow::setIcon(const QIcon &icon)
 {
@@ -983,7 +988,7 @@ void QWindow::setIcon(const QIcon &icon)
 }
 
 /*!
-    \brief Sets the window's icon in the windowing system
+    \brief Returns the window's icon in the windowing system
 
     \sa setIcon()
 */
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.h b/src/plugins/platforms/cocoa/qcocoawindow.h
index a93a391358..3230c32133 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.h
+++ b/src/plugins/platforms/cocoa/qcocoawindow.h
@@ -285,8 +285,6 @@ public: // for QNSView
     };
     QHash<quintptr, BorderRange> m_contentBorderAreas; // identifer -> uppper/lower
     QHash<quintptr, bool> m_enabledContentBorderAreas; // identifer -> enabled state (true/false)
-
-    bool m_hasWindowFilePath;
 };
 
 #ifndef QT_NO_DEBUG_STREAM
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index 217bfb3602..8f5b419f2a 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -157,7 +157,6 @@ QCocoaWindow::QCocoaWindow(QWindow *win, WId nativeHandle)
     , m_drawContentBorderGradient(false)
     , m_topContentBorderThickness(0)
     , m_bottomContentBorderThickness(0)
-    , m_hasWindowFilePath(false)
 {
     qCDebug(lcQpaCocoaWindow) << "QCocoaWindow::QCocoaWindow" << window();
 
@@ -594,6 +593,11 @@ void QCocoaWindow::setWindowTitle(const QString &title)
 
     QMacAutoReleasePool pool;
     m_view.window.title = title.toNSString();
+
+    if (title.isEmpty() && !window()->filePath().isEmpty()) {
+        // Clearing the title should restore the default filename
+        setWindowFilePath(window()->filePath());
+    }
 }
 
 void QCocoaWindow::setWindowFilePath(const QString &filePath)
@@ -602,9 +606,14 @@ void QCocoaWindow::setWindowFilePath(const QString &filePath)
         return;
 
     QMacAutoReleasePool pool;
-    QFileInfo fi(filePath);
-    [m_view.window setRepresentedFilename:fi.exists() ? filePath.toNSString() : @""];
-    m_hasWindowFilePath = fi.exists();
+
+    if (window()->title().isNull())
+        [m_view.window setTitleWithRepresentedFilename:filePath.toNSString()];
+    else
+        m_view.window.representedFilename = filePath.toNSString();
+
+    // Changing the file path may affect icon visibility
+    setWindowIcon(window()->icon());
 }
 
 void QCocoaWindow::setWindowIcon(const QIcon &icon)
@@ -612,23 +621,21 @@ void QCocoaWindow::setWindowIcon(const QIcon &icon)
     if (!isContentView())
         return;
 
-    QMacAutoReleasePool pool;
-
     NSButton *iconButton = [m_view.window standardWindowButton:NSWindowDocumentIconButton];
-    if (iconButton == nil) {
-        if (icon.isNull())
-            return;
-        NSString *title = window()->title().toNSString();
-        [m_view.window setRepresentedURL:[NSURL fileURLWithPath:title]];
-        iconButton = [m_view.window standardWindowButton:NSWindowDocumentIconButton];
+    if (!iconButton) {
+        // Window icons are only supported on macOS in combination with a document filePath
+        return;
     }
+
+    QMacAutoReleasePool pool;
+
     if (icon.isNull()) {
-        [iconButton setImage:nil];
+        NSWorkspace *workspace = [NSWorkspace sharedWorkspace];
+        [iconButton setImage:[workspace iconForFile:m_view.window.representedFilename]];
     } else {
         QPixmap pixmap = icon.pixmap(QSize(22, 22));
         NSImage *image = static_cast<NSImage *>(qt_mac_create_nsimage(pixmap));
-        [iconButton setImage:image];
-        [image release];
+        [iconButton setImage:[image autorelease]];
     }
 }
 
diff --git a/src/plugins/platforms/cocoa/qnswindowdelegate.mm b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
index 1224d138d9..cdecd86dfb 100644
--- a/src/plugins/platforms/cocoa/qnswindowdelegate.mm
+++ b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
@@ -44,6 +44,8 @@
 #include <qpa/qplatformscreen.h>
 #include <qpa/qwindowsysteminterface.h>
 
+static QRegExp whitespaceRegex = QRegExp(QStringLiteral("\\s*"));
+
 @implementation QNSWindowDelegate
 
 - (id)initWithQCocoaWindow:(QCocoaWindow *)cocoaWindow
@@ -98,7 +100,10 @@
 {
     Q_UNUSED(window);
     Q_UNUSED(menu);
-    return m_cocoaWindow && m_cocoaWindow->m_hasWindowFilePath;
+
+    // Only pop up document path if the filename is non-empty. We allow whitespace, to
+    // allow faking a window icon by setting the file path to a single space character.
+    return !whitespaceRegex.exactMatch(m_cocoaWindow->window()->filePath());
 }
 
 - (BOOL)window:(NSWindow *)window shouldDragDocumentWithEvent:(NSEvent *)event from:(NSPoint)dragImageLocation withPasteboard:(NSPasteboard *)pasteboard
@@ -107,6 +112,9 @@
     Q_UNUSED(event);
     Q_UNUSED(dragImageLocation);
     Q_UNUSED(pasteboard);
-    return m_cocoaWindow && m_cocoaWindow->m_hasWindowFilePath;
+
+    // Only allow drag if the filename is non-empty. We allow whitespace, to
+    // allow faking a window icon by setting the file path to a single space.
+    return !whitespaceRegex.exactMatch(m_cocoaWindow->window()->filePath());
 }
 @end