2 files changed, 65 insertions, 0 deletions

diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 0131959..9a94a2e 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -422,6 +422,33 @@ void MainWindow::closeEvent(QCloseEvent *event)
         }
     }
 
+    // Every composer goes with the window, and this is the LAST thing before
+    // the close is accepted: every route that turns back (Cancel, a failed
+    // sync, a refused save) has already returned above, so reaching here means
+    // the application really is quitting.
+    //
+    // A composer is deliberately parentless, so that it appears in the task
+    // switcher and stays usable while the main window is. Qt therefore does not
+    // take it down with this window, and it kept the process alive: the main
+    // window vanished, the composer stayed on screen with nothing behind it,
+    // and closing it then raised the unsaved-edits dialog for a session that
+    // had already ended.
+    //
+    // Closing rather than deleting. WA_DeleteOnClose is set on every composer,
+    // so close() is what frees them, and it lets ComposeWindow::closeEvent()
+    // run its own draft handling on the way out. The drafts have already been
+    // saved by the dialogs above, so that pass has nothing left to do; going
+    // through it anyway keeps ONE exit path rather than a second one that has
+    // to be kept in step.
+    //
+    // Iterating a COPY: closing a composer runs the `closed` handler, which
+    // mutates m_composers, and mutating a container mid-iteration is undefined.
+    const QList<QPointer<ComposeWindow>> composers = m_composers;
+    for (const QPointer<ComposeWindow> &composer : composers) {
+        if (composer)
+            composer->close();
+    }
+
     saveUiState();
     QMainWindow::closeEvent(event);
 }
diff --git a/tests/test_mainwindow.cpp b/tests/test_mainwindow.cpp
index ecaab2f..98dae12 100644
--- a/tests/test_mainwindow.cpp
+++ b/tests/test_mainwindow.cpp
@@ -267,6 +267,7 @@ private slots:
     void savingAMessageWithAHostileSubjectStaysInTheDirectory();
     void aStuckComposeRequestDoesNotHijackTheNextPaneLoad();
     void theSaveLoopToleratesAComposerClosedUnderTheDialog();
+    void quittingClosesEveryComposerRatherThanOrphaningIt();
     void forwardingCarriesTheOriginalsAttachments();
     void forwardSeedsHtmlFromTheConfigNotTheOriginal();
     void aStartupAccountScopesTheStartupQuery();
@@ -8833,6 +8834,43 @@ void TestMainWindow::aStuckComposeRequestDoesNotHijackTheNextPaneLoad()
     QCOMPARE(window.openComposerCount(), 0);
 }
 
+void TestMainWindow::quittingClosesEveryComposerRatherThanOrphaningIt()
+{
+    // A composer is a parentless top-level window, deliberately: it must appear
+    // in the task switcher and be usable while the main window is. The cost is
+    // that closing the main window does NOT take it down, so quitting left a
+    // composer on screen with no application behind it, and Qt kept the process
+    // alive for it. Reported from a hand test: the main window closed, the
+    // orphan stayed, and its own close then raised the unsaved-edits dialog for
+    // a session the user had already ended.
+    //
+    // The quit path already ASKS about those edits and saves them; what it
+    // never did was close the windows afterwards.
+    WorkerComposeFixture fixture;
+    QVERIFY2(fixture.seed({ { QStringLiteral("work"), QStringLiteral("work"),
+                              QString(), QStringLiteral("/bin/true"),
+                              QStringLiteral("you@example.org") } },
+                          QStringLiteral("work/inbox")),
+             qPrintable(fixture.backed.error()));
+
+    MainWindow window(fixture.backed.config());
+    QTRY_VERIFY_WITH_TIMEOUT(!window.mailRootForTesting().isEmpty(), 15000);
+
+    // Two, so the fix cannot be "close the last one" and pass.
+    QVERIFY2(window.openComposerForTest(), "no composer opened");
+    QVERIFY2(window.openComposerForTest(), "no second composer opened");
+    QCOMPARE(window.openComposerCount(), 2);
+
+    // Clean composers: the point here is the CLOSE, not the unsaved-edits
+    // dialog, which has its own tests and would block this one on a modal.
+    window.show();
+    window.close();
+
+    // deleteLater() is how a composer goes away, so the count settles on the
+    // next event-loop pass rather than synchronously.
+    QTRY_COMPARE_WITH_TIMEOUT(window.openComposerCount(), 0, 5000);
+}
+
 void TestMainWindow::theSaveLoopToleratesAComposerClosedUnderTheDialog()
 {
     // The regression for a measured use-after-free. composersBlockingQuit()