Remove catch from Scheduler build

Makes debugging errors harder.

In this case, we can use `finally` instead.

Author: acdlite

packages/scheduler/src/forks/SchedulerDOM.js

@@ -519,8 +519,13 @@ const performWorkUntilDeadline = () => {
     // the message event.
     deadline = currentTime + yieldInterval;
     const hasTimeRemaining = true;
+
+    // Use a variable to track whether something task throws, instead of a try-
+    // catch, since that makes some debugging techniques harder.
+    let didError = true;
     try {
       const hasMoreWork = scheduledHostCallback(hasTimeRemaining, currentTime);
+      didError = false;
       if (!hasMoreWork) {
         isMessageLoopRunning = false;
         scheduledHostCallback = null;
@@ -529,11 +534,12 @@ const performWorkUntilDeadline = () => {
         // of the preceding one.
         port.postMessage(null);
       }
-    } catch (error) {
-      // If a scheduler task throws, exit the current browser task so the
-      // error can be observed.
-      port.postMessage(null);
-      throw error;
+    } finally {
+      if (didError) {
+        // If a scheduler task throws, exit the current browser task so the
+        // error can be observed.
+        port.postMessage(null);
+      }
     }
   } else {
     isMessageLoopRunning = false;

packages/scheduler/src/forks/SchedulerPostTaskOnly.js

@@ -512,21 +512,27 @@ const performWorkUntilDeadline = () => {
     // the message event.
     deadline = currentTime + yieldInterval;
     const hasTimeRemaining = true;
+
+    // Use a variable to track whether something task throws, instead of a try-
+    // catch, since that makes some debugging techniques harder.
+    let didError = true;
     try {
       const hasMoreWork = scheduledHostCallback(hasTimeRemaining, currentTime);
+      didError = false;
       if (!hasMoreWork) {
         isTaskLoopRunning = false;
         scheduledHostCallback = null;
       } else {
-        // If there's more work, schedule the next message event at the end
-        // of the preceding one.
+        // If there's more work, schedule the next browser task at the end of
+        // the preceding one.
+        postTask(performWorkUntilDeadline);
+      }
+    } finally {
+      if (didError) {
+        // If a scheduler task throws, exit the current browser task so the
+        // error can be observed.
         postTask(performWorkUntilDeadline);
       }
-    } catch (error) {
-      // If a scheduler task throws, exit the current browser task so the
-      // error can be observed.
-      postTask(performWorkUntilDeadline);
-      throw error;
     }
   } else {
     isTaskLoopRunning = false;