Bug 1571863 Part 2 - Handle failures when communicating with source fronts, and reenable browser_dbg-worker-scopes.js, r=loganfsmyth.

Depends on D50762

Differential Revision: https://phabricator.services.mozilla.com/D50763

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

devtools/client/debugger/src/actions/sources/loadSourceText.js

@@ -73,18 +73,32 @@ async function loadSource(
     return result;
   }
 
-  const actors = getSourceActorsForSource(state, source.id);
-  if (!actors.length) {
-    throw new Error("No source actor for loadSource");
+  // We only need the source text from one actor, but messages sent to retrieve
+  // the source might fail if the actor has or is about to shut down. Keep
+  // trying with different actors until one request succeeds.
+  let response;
+  const handledActors = new Set();
+  while (true) {
+    const actors = getSourceActorsForSource(state, source.id);
+    const actor = actors.find(({ actor: a }) => !handledActors.has(a));
+    if (!actor) {
+      throw new Error("Unknown source");
+    }
+    handledActors.add(actor.actor);
+
+    try {
+      telemetry.start(loadSourceHistogram, source);
+      response = await client.sourceContents(actor);
+      telemetry.finish(loadSourceHistogram, source);
+      break;
+    } catch (e) {
+      console.warn(`sourceContents failed: ${e}`);
+    }
   }
 
-  telemetry.start(loadSourceHistogram, source);
-  const response = await client.sourceContents(actors[0]);
-  telemetry.finish(loadSourceHistogram, source);
-
   return {
-    text: response.source,
-    contentType: response.contentType || "text/javascript",
+    text: (response: any).source,
+    contentType: (response: any).contentType || "text/javascript",
   };
 }
 

devtools/client/debugger/src/actions/sources/tests/loadSource.spec.js

@@ -268,7 +268,7 @@ describe("loadSourceText", () => {
       : null;
     expect(
       content && isRejected(content) && typeof content.value === "string"
-        ? content.value.indexOf("unknown source")
+        ? content.value.indexOf("Unknown source")
         : -1
     ).not.toBe(-1);
   });

devtools/client/debugger/src/client/firefox/commands.js

@@ -122,7 +122,7 @@ function lookupThreadFront(thread: string) {
 
 function listThreadFronts() {
   const targetList = (Object.values(getTargetsMap()): any);
-  return targetList.map(target => target.threadFront);
+  return targetList.map(target => target.threadFront).filter(t => !!t);
 }
 
 function forEachThread(iteratee) {
@@ -521,10 +521,11 @@ async function getSourceActorBreakableLines({
   thread,
   actor,
 }: SourceActor): Promise<Array<number>> {
-  const sourceThreadFront = lookupThreadFront(thread);
-  const sourceFront = sourceThreadFront.source({ actor });
+  let sourceFront;
   let actorLines = [];
   try {
+    const sourceThreadFront = lookupThreadFront(thread);
+    sourceFront = sourceThreadFront.source({ actor });
     actorLines = await sourceFront.getBreakableLines();
   } catch (e) {
     // Handle backward compatibility
@@ -532,10 +533,11 @@ async function getSourceActorBreakableLines({
       e.message &&
       e.message.match(/does not recognize the packet type getBreakableLines/)
     ) {
-      const pos = await sourceFront.getBreakpointPositionsCompressed();
+      const pos = await (sourceFront: any).getBreakpointPositionsCompressed();
       actorLines = Object.keys(pos).map(line => Number(line));
-    } else if (!e.message || !e.message.match(/Connection closed/)) {
-      throw e;
+    } else {
+      // Other exceptions could be due to the target thread being shut down.
+      console.warn(`getSourceActorBreakableLines failed: ${e}`);
     }
   }
 

devtools/client/debugger/test/mochitest/browser.ini

@@ -160,7 +160,7 @@ skip-if = os == "win"
 [browser_dbg-windowless-workers-early-breakpoint.js]
 [browser_dbg-worker-exception.js]
 [browser_dbg-worker-scopes.js]
-skip-if = true #Bug 1456013, Bug 1559547, Bug 1571863
+skip-if = (os == 'linux' && debug) || (os == 'linux' && asan) || ccov  #Bug 1456013, Bug 1559547
 [browser_dbg-event-handler.js]
 [browser_dbg-event-breakpoints.js]
 [browser_dbg-eval-throw.js]

devtools/client/debugger/test/mochitest/browser_dbg-worker-scopes.js

@@ -2,10 +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/>. */
 
-// This error shows up sometimes when running the test, and while this is a
-// strange problem that shouldn't be happening it doesn't prevent the test from
-// completing successfully.
 PromiseTestUtils.whitelistRejectionsGlobally(/Current state is running/);
+PromiseTestUtils.whitelistRejectionsGlobally(/Connection closed/);
 
 function findNode(dbg, text) {
   for (let index = 0; ; index++) {