1 files changed, 72 insertions, 0 deletions
diff --git a/browser/components/downloads/test/browser/browser_iframe_gone_mid_download.js b/browser/components/downloads/test/browser/browser_iframe_gone_mid_download.js
new file mode 100644
index 0000000000..a1b82fb9c2
--- /dev/null
+++ b/browser/components/downloads/test/browser/browser_iframe_gone_mid_download.js
@@ -0,0 +1,72 @@
+const SAVE_PER_SITE_PREF = "browser.download.lastDir.savePerSite";
+
+function test_deleted_iframe(perSitePref, windowOptions = {}) {
+  return async function () {
+    await SpecialPowers.pushPrefEnv({
+      set: [[SAVE_PER_SITE_PREF, perSitePref]],
+    });
+    let { DownloadLastDir } = ChromeUtils.importESModule(
+      "resource://gre/modules/DownloadLastDir.sys.mjs"
+    );
+
+    let win = await BrowserTestUtils.openNewBrowserWindow(windowOptions);
+    let tab = await BrowserTestUtils.openNewForegroundTab(
+      win.gBrowser,
+      "about:mozilla"
+    );
+
+    let doc = tab.linkedBrowser.contentDocument;
+    let iframe = doc.createElement("iframe");
+    doc.body.appendChild(iframe);
+
+    ok(iframe.contentWindow, "iframe should have a window");
+    let gDownloadLastDir = new DownloadLastDir(iframe.contentWindow);
+    let cw = iframe.contentWindow;
+    let promiseIframeWindowGone = new Promise((resolve, reject) => {
+      Services.obs.addObserver(function obs(subject, topic) {
+        if (subject == cw) {
+          Services.obs.removeObserver(obs, topic);
+          resolve();
+        }
+      }, "dom-window-destroyed");
+    });
+    iframe.remove();
+    await promiseIframeWindowGone;
+    cw = null;
+    ok(!iframe.contentWindow, "Managed to destroy iframe");
+
+    let someDir = "blah";
+    try {
+      someDir = await gDownloadLastDir.getFileAsync("http://www.mozilla.org/");
+    } catch (ex) {
+      ok(
+        false,
+        "Got an exception trying to get the directory where things should be saved."
+      );
+      console.error(ex);
+    }
+    // NB: someDir can legitimately be null here when set, hence the 'blah' workaround:
+    isnot(
+      someDir,
+      "blah",
+      "Should get a file even after the window was destroyed."
+    );
+
+    try {
+      gDownloadLastDir.setFile("http://www.mozilla.org/", null);
+    } catch (ex) {
+      ok(
+        false,
+        "Got an exception trying to set the directory where things should be saved."
+      );
+      console.error(ex);
+    }
+
+    await BrowserTestUtils.closeWindow(win);
+  };
+}
+
+add_task(test_deleted_iframe(false));
+add_task(test_deleted_iframe(false));
+add_task(test_deleted_iframe(true, { private: true }));
+add_task(test_deleted_iframe(true, { private: true }));