Bug 1866589 - Enable ESLint rule no-unreachable for dom/*. r=dom-core,dom-worker-reviewers,mccr8,smaug

Differential Revision: https://phabricator.services.mozilla.com/D194662

.eslintrc.js

@@ -497,7 +497,6 @@ module.exports = {
         "no-shadow": "off",
         "no-sparse-arrays": "off",
         "no-throw-literal": "off",
-        "no-unreachable": "off",
         "no-useless-call": "off",
         "no-useless-concat": "off",
       },

dom/events/test/clipboard/simple_navigator_clipboard_read.html

@@ -18,7 +18,6 @@
         let items = await navigator.clipboard.read();
         if (items.length != 1) {
           throw Error(`incorrect number of clipboard item (${items.length})`);
-          return;
         }
 
         let item = items[0];

dom/media/webrtc/tests/mochitests/test_peerConnection_throwInCallbacks.html

@@ -38,7 +38,6 @@ runNetworkTest(function () {
       finish();
     }
     throw new Error("window.onerror may throw");
-    return false;
   }
 
   let pc0, pc1, pc2;

dom/media/webspeech/recognition/test/test_online_http.html

@@ -40,14 +40,12 @@ that audio is being properly encoded
     while (true) {
       if (performance.now() - start > 10000) {
         return false;
-        break;
       }
       analyser.getByteFrequencyData(data);
       if (data[binIndexForFrequency(200)] < 50 &&
           data[binIndexForFrequency(440)] > 180 &&
           data[binIndexForFrequency(1000)] < 50) {
         return true;
-        break;
       }
       await new Promise(r => requestAnimationFrame(r));
     }

dom/media/webspeech/recognition/test/test_online_http_webkit.html

@@ -40,14 +40,12 @@ that audio is being properly encoded
     while (true) {
       if (performance.now() - start > 10000) {
         return false;
-        break;
       }
       analyser.getByteFrequencyData(data);
       if (data[binIndexForFrequency(200)] < 50 &&
           data[binIndexForFrequency(440)] > 180 &&
           data[binIndexForFrequency(1000)] < 50) {
         return true;
-        break;
       }
       await new Promise(r => requestAnimationFrame(r));
     }

dom/payments/test/test_retryPayment.html

@@ -148,13 +148,10 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1435161
     try {
       await payResponse.retry(validationErrors);
       ok(false, `${testName}: Unexpected success when retry the PaymentResponse.`);
-      return;
     } catch(err) {
       is(err.name,
          "InvalidStateError",
          expectedErrMsg(testName, "InvalidStateError", err.name, "retrying"));
-      await requestChromeAction("finish-test");
-      return;
     }
     await requestChromeAction("finish-test");
   }

dom/security/test/csp/test_redirects.html

@@ -19,10 +19,9 @@ var path = "/tests/dom/security/test/csp/";
 
 // debugging
 function log(s) {
-  return;
-  dump("**" + s + "\n");
-  var log = document.getElementById("log");
-  log.textContent = log.textContent+s+"\n";
+  // dump("**" + s + "\n");
+  // var log = document.getElementById("log");
+  // log.textContent = log.textContent+s+"\n";
 }
 
 SpecialPowers.registerObservers("csp-on-violate-policy");

dom/serviceworkers/test/strict_mode_warning.js

@@ -1,4 +1,5 @@
 function f() {
   return 1;
+  // eslint-disable-next-line no-unreachable
   return 2;
 }

dom/serviceworkers/test/test_devtools_bypass_serviceworker.html

@@ -53,7 +53,6 @@ async function testBypassSW () {
     }
 
     throw("Unexpected error");
-    return;
   }
 
   let docShell = SpecialPowers.wrap(window).docShell;

dom/workers/test/WorkerDebuggerGlobalScope.reportError_debugger.js

@@ -7,6 +7,5 @@ this.onmessage = function (event) {
       break;
     case "throw":
       throw new Error("thrown");
-      break;
   }
 };

dom/workers/test/WorkerDebugger_sharedWorker.js

@@ -11,7 +11,6 @@ self.onconnect = function (event) {
         close();
         // Let's loop forever.
         while (1) {}
-        break;
     }
   };
 };

dom/workers/test/dynamicImport_worker.js

@@ -10,6 +10,5 @@ onmessage = function (event) {
       break;
     default:
       throw new Error("Bad message: " + event.data);
-      break;
   }
 };

dom/workers/test/importScripts_worker.js

@@ -56,7 +56,6 @@ onmessage = function (event) {
       break;
     default:
       throw new Error("Bad message: " + event.data);
-      break;
   }
 };
 

dom/workers/test/recursion_worker.js

@@ -42,5 +42,6 @@ onmessage = function (event) {
       throw "Weird number of messages: " + messageCount;
   }
 
+  // eslint-disable-next-line no-unreachable
   throw "Impossible to get here!";
 };

dom/workers/test/sharedWorker_sharedWorker.js

@@ -80,6 +80,7 @@ onconnect = function (event) {
   // at us.
   (function () {
     return;
+    // eslint-disable-next-line no-unreachable
     1;
   });
 

dom/workers/test/test_sharedWorker.html

@@ -22,7 +22,7 @@
         const sentMessage = "ping";
         const errorFilename = href.substring(0, href.lastIndexOf("/") + 1) +
                               filename;
-        const errorLine = 97;
+        const errorLine = 98;
         const errorColumn = 11;
 
         var worker = new SharedWorker(filename);