Bug 1810979 - [devtools] Fix source tab names for sources with no urls r=nchevobbe

Found a bug where we just showing `SOURCE` in the tab for sources without urls,
instead of the actual source ids. e.g `SOURCE` instead of `SOURCEsource39`
This patch fixes the issue to show
- The source id ie. `(source39)`
- No need for the duplicate `SOURCE`

Differential Revision: https://phabricator.services.mozilla.com/D168245

devtools/client/debugger/src/utils/source.js

@@ -189,9 +189,7 @@ function resolveFileURL(
 }
 
 export function getFormattedSourceId(id) {
-  const firstIndex = id.indexOf("/");
-  const secondIndex = id.indexOf("/", firstIndex);
-  return `SOURCE${id.slice(firstIndex, secondIndex)}`;
+  return id.substring(id.lastIndexOf("/") + 1);
 }
 
 /**

devtools/client/debugger/test/mochitest/browser_dbg-tabs-without-urls.js

@@ -2,8 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
 
-// Test that URL-less sources have tabs added to the UI but
-// do not persist upon reload
+// Test that URL-less sources have tabs added to the UI, are named correctly
+// and do not persist upon reload
 
 "use strict";
 
@@ -15,28 +15,32 @@ add_task(async function() {
   );
 
   await selectSource(dbg, "simple1.js");
-  await selectSource(dbg, "simple2.js");
-
-  is(countTabs(dbg), 2);
+  is(countTabs(dbg), 1, "Only the `simple.js` source tab exists");
 
   invokeInTab("doEval");
   await waitForPaused(dbg);
-  await resume(dbg);
-  is(countTabs(dbg), 3);
 
-  invokeInTab("doEval");
-  await waitForPaused(dbg);
+  is(countTabs(dbg), 2, "The new eval tab is now added");
+
+  info("Assert that the eval source the tab source name correctly");
+  ok(
+    /source\d+/g.test(getTabContent(dbg, 0)),
+    "The tab name pattern is correct"
+  );
+
   await resume(dbg);
-  is(countTabs(dbg), 4);
 
   // Test reloading the debugger
   await reload(dbg, "simple1.js", "simple2.js");
-  is(countTabs(dbg), 2);
-
-  // TODO: This is here to make this test less flakey because otherwise the
-  // test will end while the files are still loading, which will stop all
-  // in-progress requests causing uncaught rejections when querying
-  // 'getBreakpointPositionsCompressed'.
-  await selectSource(dbg, "simple1.js");
-  await selectSource(dbg, "simple2.js");
+  is(countTabs(dbg), 1, "The eval source tab is no longer available");
 });
+
+/*
+ * Get the tab content for the specific tab
+ *
+ * @param {Number} index - index of the tab to get the source content
+ */
+function getTabContent(dbg, index) {
+  const tabs = findElement(dbg, "sourceTabs").children;
+  return tabs[index]?.innerText || "";
+}