Bug 1543190 - Fix console autocomplete throwing for null. r=nchevobbe

Differential Revision: https://phabricator.services.mozilla.com/D55391

--HG--
extra : moz-landing-system : lando

devtools/client/webconsole/test/browser/_jsterm.ini

@@ -43,6 +43,7 @@ support-files =
 [browser_jsterm_autocomplete_inside_text.js]
 [browser_jsterm_autocomplete_native_getters.js]
 [browser_jsterm_autocomplete_nav_and_tab_key.js]
+[browser_jsterm_autocomplete_null.js]
 [browser_jsterm_autocomplete_paste_undo.js]
 [browser_jsterm_autocomplete_race_on_enter.js]
 [browser_jsterm_autocomplete_return_key_no_selection.js]

devtools/client/webconsole/test/browser/browser_jsterm_autocomplete_null.js

@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function() {
+  await pushPref("devtools.chrome.enabled", true);
+  await addTab("about:blank");
+
+  info(`Open browser console with ctrl-shift-j`);
+  const opened = waitForBrowserConsole();
+  EventUtils.synthesizeKey("j", { accelKey: true, shiftKey: true }, window);
+  const hud = await opened;
+  const { jsterm } = hud;
+  const { autocompletePopup: popup } = jsterm;
+
+  info(`Clear existing messages`);
+  const onMessagesCleared = hud.ui.once("messages-cleared");
+  await clearOutput(hud);
+  await onMessagesCleared;
+
+  info(`Create a null variable`);
+  execute(hud, "globalThis.nullVar = null;");
+
+  info(`Check completion suggestions for "null"`);
+  const onPopUpOpen = popup.once("popup-opened");
+  EventUtils.sendString("null", hud.iframeWindow);
+  await onPopUpOpen;
+  ok(popup.isOpen, "popup is open");
+  const expectedPopupItems = ["null", "nullVar"];
+  is(
+    popup.items.map(i => i.label).join("-"),
+    expectedPopupItems.join("-"),
+    "popup has expected items"
+  );
+
+  info(`Check completion suggestions for "null."`);
+  let onAutocompleteUpdated = jsterm.once("autocomplete-updated");
+  EventUtils.sendString(".", hud.iframeWindow);
+  await onAutocompleteUpdated;
+  is(popup.itemCount, 0, "popup has no items");
+
+  info(`Check completion suggestions for "null"`);
+  onAutocompleteUpdated = jsterm.once("autocomplete-updated");
+  EventUtils.synthesizeKey("KEY_Backspace", undefined, hud.iframeWindow);
+  await onAutocompleteUpdated;
+  is(popup.itemCount, 2, "popup has 2 items");
+
+  info(`Check completion suggestions for "nullVar"`);
+  onAutocompleteUpdated = jsterm.once("autocomplete-updated");
+  EventUtils.sendString("Var.", hud.iframeWindow);
+  await onAutocompleteUpdated;
+  is(popup.itemCount, 0, "popup has no items");
+
+  info(`Check that no error was logged`);
+  await waitFor(() => findMessage(hud, "", ".message.error")).then(
+    message => {
+      ok(false, `Got error ${JSON.stringify(message.textContent)}`);
+    },
+    error => {
+      if (!error.includes("waitFor - timed out")) {
+        throw error;
+      }
+      ok(true, `No error was logged`);
+    }
+  );
+
+  info(`Cleanup`);
+  execute(hud, "delete globalThis.nullVar;");
+});

devtools/shared/webconsole/js-property-provider.js

@@ -980,9 +980,9 @@ var DebuggerEnvironmentSupport = {
 
     // FIXME: Need actual UI, bug 941287.
     if (
-      result === undefined ||
-      result.optimizedOut ||
-      result.missingArguments
+      result == null ||
+      (typeof result == "object" &&
+        (result.optimizedOut || result.missingArguments))
     ) {
       return null;
     }