Bug 1920834 - Implement a nightly pref to toggle experimental conversation view. r=laurel,vineet

Differential Revision: https://phabricator.services.mozilla.com/D223442

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

mail/app/profile/all-thunderbird.js

@@ -1417,3 +1417,8 @@ pref("mail.inappnotifications.refreshInterval", 21600000);
 pref("mail.inappnotifications.url", "https://notifications-stage.thunderbird.net/notifications.json");
 // Disables all filtering of in-app notifications, useful for testing.
 pref("mail.inappnotifications.bypass-filtering", false);
+
+#ifdef NIGHTLY_BUILD
+// Enable the new experimental conversation view based on Gloda.
+pref("mail.thread.conversation.enabled", false);
+#endif

mail/components/MailGlue.sys.mjs

@@ -1333,6 +1333,11 @@ function reportPreferences() {
     booleanPrefs.push("browser.crashReports.unsubmittedCheck.autoSubmit2");
   }
 
+  // Nightly experimental prefs.
+  if (AppConstants.NIGHTLY_BUILD) {
+    booleanPrefs.push("mail.thread.conversation.enabled");
+  }
+
   // Fetch and report preference values
   for (const prefName of booleanPrefs) {
     const prefValue = Services.prefs.getBoolPref(prefName, false);

mail/components/preferences/general.inc.xhtml

@@ -769,6 +769,22 @@
                     other-cases-text-label.value"/>
         </hbox>
       </hbox>
+#ifdef NIGHTLY_BUILD
+      <separator/>
+      <vbox>
+        <hbox class="align-baseline">
+          <html:legend data-l10n-id="conversation-view-legend"></html:legend>
+          <span class="label-experiment" data-l10n-id="label-experiment"></span>
+        </hbox>
+        <vbox>
+          <checkbox id="conversationView"
+                    data-l10n-id="conversation-view-checkbox-label"
+                    preference="mail.thread.conversation.enabled"/>
+          <description data-l10n-id="conversation-view-checkbox-description"
+                       class="tip-caption indent"/>
+        </vbox>
+      </vbox>
+#endif
     </html:fieldset>
     </html:div>
 

mail/components/preferences/general.js

@@ -133,6 +133,11 @@ if (AppConstants.MOZ_UPDATER) {
   }
 }
 
+// Nightly experimental prefs.
+if (AppConstants.NIGHTLY_BUILD) {
+  Preferences.add({ id: "mail.thread.conversation.enabled", type: "bool" });
+}
+
 var gGeneralPane = {
   // The set of types the app knows how to handle. A map of HandlerInfoWrapper
   // objects, indexed by type.

mail/components/preferences/test/browser/browser_general.js

@@ -155,6 +155,14 @@ add_task(async () => {
       pref: "mail.threadpane.table.horizontal_scroll",
     }
   );
+
+  // Nightly experimental prefs.
+  if (AppConstants.NIGHTLY_BUILD) {
+    await testCheckboxes("paneGeneral", "readingAndDisplayCategory", {
+      checkboxID: "conversationView",
+      pref: "mail.thread.conversation.enabled",
+    });
+  }
 });
 
 add_task(async () => {

mail/locales/en-US/messenger/preferences/preferences.ftl

@@ -540,6 +540,15 @@ table-layout-horizontal-scroll-label =
     .label = Allow horizontal scroll
     .accesskey = h
 
+conversation-view-legend = Conversation view
+
+conversation-view-checkbox-label =
+    .label = Enable conversation view
+    .accesskey = c
+conversation-view-checkbox-description = Experimental feature based on Gloda, use it at your own risk
+
+label-experiment = Experimental
+
 ## Compose Tab
 
 forward-label =

mail/themes/shared/mail/preferences/preferences.css

@@ -1134,3 +1134,21 @@ calendar-notifications-setting {
     vertical-align: sub;
   }
 }
+
+/* Feature labels */
+
+.align-baseline {
+  align-items: baseline;
+}
+
+.label-experiment {
+  font-size: 0.85rem;
+  line-height: 1;
+  text-transform: uppercase;
+  display: inline-block;
+  padding: 3px;
+  background-color: var(--color-warning-default);
+  color: var(--color-text-warning);
+  border-radius: 3px;
+  margin-inline-start: 12px;
+}