Merge pull request #1172 from glimmerjs/remove-try-catch-in-updating-vm

glimmerjs · Oct 13, 2020 · c00d700 · c00d700
2 parents 2a5457a + 3269ca3
commit c00d700
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Showing 2 changed files with 59 additions and 30 deletions.
diff --git a/packages/@glimmer/runtime/lib/vm/append.ts b/packages/@glimmer/runtime/lib/vm/append.ts
@@ -548,6 +548,35 @@ export default class VM implements PublicVM, InternalVM {
   /// EXECUTION
 
   execute(initialize?: (vm: this) => void): RenderResult {
+    if (DEBUG) {
+      let hasErrored = true;
+      try {
+        let value = this._execute(initialize);
+
+        // using a boolean here to avoid breaking ergonomics of "pause on uncaught exceptions"
+        // which would happen with a `catch` + `throw`
+        hasErrored = false;
+
+        return value;
+      } finally {
+        if (hasErrored) {
+          // If any existing blocks are open, due to an error or something like
+          // that, we need to close them all and clean things up properly.
+          let elements = this.elements();
+
+          while (elements.hasBlocks) {
+            elements.popBlock();
+          }
+
+          resetTracking();
+        }
+      }
+    } else {
+      return this._execute(initialize);
+    }
+  }
+
+  private _execute(initialize?: (vm: this) => void): RenderResult {
     if (LOCAL_SHOULD_LOG) {
       console.log(`EXECUTING FROM ${this[INNER_VM].fetchRegister($pc)}`);
     }
@@ -556,23 +585,9 @@ export default class VM implements PublicVM, InternalVM {
 
     let result: RichIteratorResult<null, RenderResult>;
 
-    try {
-      while (true) {
-        result = this.next();
-        if (result.done) break;
-      }
-    } catch (e) {
-      // If any existing blocks are open, due to an error or something like
-      // that, we need to close them all and clean things up properly.
-      let elements = this.elements();
-
-      while (elements.hasBlocks) {
-        elements.popBlock();
-      }
-
-      resetTracking();
-
-      throw e;
+    while (true) {
+      result = this.next();
+      if (result.done) break;
     }
 
     return result.value;

diff --git a/packages/@glimmer/runtime/lib/vm/update.ts b/packages/@glimmer/runtime/lib/vm/update.ts
@@ -1,3 +1,4 @@
+import { DEBUG } from '@glimmer/env';
 import {
   Bounds,
   DynamicScope,
@@ -41,27 +42,40 @@ export default class UpdatingVM {
   }
 
   execute(opcodes: UpdatingOpcode[], handler: ExceptionHandler) {
+    if (DEBUG) {
+      let hasErrored = true;
+      try {
+        this._execute(opcodes, handler);
+
+        // using a boolean here to avoid breaking ergonomics of "pause on uncaught exceptions"
+        // which would happen with a `catch` + `throw`
+        hasErrored = false;
+      } finally {
+        if (hasErrored) {
+          resetTracking();
+        }
+      }
+    } else {
+      this._execute(opcodes, handler);
+    }
+  }
+
+  private _execute(opcodes: UpdatingOpcode[], handler: ExceptionHandler) {
     let { frameStack } = this;
 
     this.try(opcodes, handler);
 
-    try {
-      while (true) {
-        if (frameStack.isEmpty()) break;
-
-        let opcode = this.frame.nextStatement();
+    while (true) {
+      if (frameStack.isEmpty()) break;
 
-        if (opcode === undefined) {
-          frameStack.pop();
-          continue;
-        }
+      let opcode = this.frame.nextStatement();
 
-        opcode.evaluate(this);
+      if (opcode === undefined) {
+        frameStack.pop();
+        continue;
       }
-    } catch (e) {
-      resetTracking();
 
-      throw e;
+      opcode.evaluate(this);
     }
   }