Support for await using

babel · May 17, 2023 · dad4497 · dad4497
1 parent 52ce528
commit dad4497
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Showing 9 changed files with 103 additions and 31 deletions.
diff --git a/packages/babel-helpers/src/helpers-generated.ts b/packages/babel-helpers/src/helpers-generated.ts
@@ -59,7 +59,7 @@ export default Object.freeze({
   ),
   dispose: helper(
     "7.0.0-beta.0",
-    "function dispose_SuppressedError(suppressed,error){return dispose_SuppressedError=function(suppressed,error){this.suppressed=suppressed,this.error=error,this.stack=(new Error).stack},dispose_SuppressedError.prototype=Object.create(Error.prototype,{constructor:{value:dispose_SuppressedError,writable:!0,configurable:!0}}),new dispose_SuppressedError(suppressed,error)}export default function _dispose(stack,error,hasError,SuppressedError){for(;stack.length>0;){const r=stack.pop();try{r.d.call(r.v)}catch(e){error=hasError?new(SuppressedError||dispose_SuppressedError)(e,error):e,hasError=!0}}if(hasError)throw error}",
+    "function dispose_SuppressedError(suppressed,error){return dispose_SuppressedError=function(suppressed,error){this.suppressed=suppressed,this.error=error,this.stack=(new Error).stack},dispose_SuppressedError.prototype=Object.create(Error.prototype,{constructor:{value:dispose_SuppressedError,writable:!0,configurable:!0}}),new dispose_SuppressedError(suppressed,error)}export default function _dispose(stack,error,hasError,SuppressedError){function next(){if(0!==stack.length){var r=stack.pop();if(r.a)return r.d.call(r.v).then(next,err);try{r.d.call(r.v)}catch(e){return err(e)}return next()}if(hasError)throw error}function err(e){return error=hasError?new(SuppressedError||dispose_SuppressedError)(e,error):e,hasError=!0,next()}return next()}",
   ),
   iterableToArrayLimit: helper(
     "7.0.0-beta.0",
@@ -87,7 +87,7 @@ export default Object.freeze({
   ),
   using: helper(
     "7.0.0-beta.0",
-    'export default function _using(stack,value){if(null!=value){var dispose=value[Symbol.dispose||Symbol.for("Symbol.dispose")];if("function"!=typeof dispose)throw new TypeError("Property [Symbol.dispose] is not a function.");stack.push({v:value,d:dispose})}return value}',
+    'export default function _using(stack,value,isAwait){if(null!=value){var dispose=value[Symbol.dispose||Symbol.for("Symbol.dispose")];if("function"!=typeof dispose)throw new TypeError("Property [Symbol.dispose] is not a function.");stack.push({v:value,d:dispose,a:isAwait})}return value}',
   ),
   wrapRegExp: helper(
     "7.19.0",

diff --git a/packages/babel-helpers/src/helpers/dispose.js b/packages/babel-helpers/src/helpers/dispose.js
@@ -16,16 +16,33 @@ function dispose_SuppressedError(suppressed, error) {
 }
 
 export default function _dispose(stack, error, hasError, SuppressedError) {
-  while (stack.length > 0) {
-    const r = stack.pop();
-    try {
-      r.d.call(r.v);
-    } catch (e) {
-      error = hasError
-        ? new (SuppressedError || dispose_SuppressedError)(e, error)
-        : e;
-      hasError = true;
+  function next() {
+    if (stack.length === 0) {
+      if (hasError) throw error;
+      return;
     }
+
+    var r = stack.pop();
+    if (r.a) {
+      return r.d.call(r.v).then(next, err);
+    } else {
+      try {
+        r.d.call(r.v);
+      } catch (e) {
+        return err(e);
+      }
+      return next();
+    }
+  }
+
+  function err(e) {
+    error = hasError
+      ? new (SuppressedError || dispose_SuppressedError)(e, error)
+      : e;
+    hasError = true;
+
+    return next();
   }
-  if (hasError) throw error;
+
+  return next();
 }
diff --git a/packages/babel-helpers/src/helpers/using.js b/packages/babel-helpers/src/helpers/using.js
@@ -1,13 +1,13 @@
 /* @minVersion 7.0.0-beta.0 */
 
-export default function _using(stack, value) {
+export default function _using(stack, value, isAwait) {
   if (value !== null && value !== void 0) {
     // core-js-pure uses Symbol.for("Symbol.dispose").
     var dispose = value[Symbol.dispose || Symbol.for("Symbol.dispose")];
     if (typeof dispose !== "function") {
       throw new TypeError(`Property [Symbol.dispose] is not a function.`);
     }
-    stack.push({ v: value, d: dispose });
+    stack.push({ v: value, d: dispose, a: isAwait });
   }
   return value;
 }
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/src/index.ts b/packages/babel-plugin-proposal-explicit-resource-management/src/index.ts
@@ -3,6 +3,11 @@ import syntacExplicitResourceManagement from "@babel/plugin-syntax-explicit-reso
 import { types as t, template } from "@babel/core";
 import type { NodePath } from "@babel/traverse";
 
+function isUsingDeclaration(node: t.Node): node is t.VariableDeclaration {
+  if (!t.isVariableDeclaration(node)) return false;
+  return node.kind === "using" || node.kind === "await using";
+}
+
 export default declare(api => {
   // TOOD: assert version 7.22.0
   api.assertVersion(7);
@@ -13,15 +18,15 @@ export default declare(api => {
 
     visitor: {
       VariableDeclaration(path) {
-        if (path.node.kind === "using") {
+        if (path.node.kind === "using" || path.node.kind === "await using") {
           throw path.buildCodeFrameError(
             `"using" declaration at the top-level of modules is not supported yet.`,
           );
         }
       },
       ForOfStatement(path: NodePath<t.ForOfStatement>) {
         const { left } = path.node;
-        if (!t.isVariableDeclaration(left, { kind: "using" })) return;
+        if (!isUsingDeclaration(left)) return;
 
         const { id } = left.declarations[0];
         const tmpId = path.scope.generateUidIdentifierBasedOnNode(id);
@@ -37,23 +42,42 @@ export default declare(api => {
       },
       BlockStatement(path, state) {
         let stackId: t.Identifier | null = null;
+        let needsAwait = false;
+
         for (const node of path.node.body) {
-          if (!t.isVariableDeclaration(node, { kind: "using" })) continue;
-          node.kind = "const";
+          if (!isUsingDeclaration(node)) continue;
           stackId ??= path.scope.generateUidIdentifier("stack");
+          const isAwaitUsing = node.kind === "await using";
+          needsAwait ||= isAwaitUsing;
 
+          node.kind = "const";
           node.declarations.forEach(decl => {
-            decl.init = t.callExpression(state.addHelper("using"), [
-              t.cloneNode(stackId),
-              decl.init,
-            ]);
+            const args = [t.cloneNode(stackId), decl.init];
+            if (isAwaitUsing) args.push(t.booleanLiteral(true));
+            decl.init = t.callExpression(state.addHelper("using"), args);
           });
         }
         if (!stackId) return;
 
         const errorId = path.scope.generateUidIdentifier("error");
         const hasErrorId = path.scope.generateUidIdentifier("hasError");
 
+        let disposeCall: t.Expression = t.callExpression(
+          state.addHelper("dispose"),
+          [
+            t.cloneNode(stackId),
+            t.cloneNode(errorId),
+            t.cloneNode(hasErrorId),
+            // Pass SuppressedError so that it can be used with "pure"
+            // polyfills that do not compile the contents of runtime
+            // helpers.
+            template.expression.ast`
+              typeof SuppressedError !== undefined && SuppressedError
+            `,
+          ],
+        );
+        if (needsAwait) disposeCall = t.awaitExpression(disposeCall);
+
         const replacement = template.statement.ast`
           try {
             var ${stackId} = [];
@@ -62,15 +86,7 @@ export default declare(api => {
             var ${errorId} = _;
             var ${hasErrorId} = true;
           } finally {
-            ${state.addHelper("dispose")}(
-              ${t.cloneNode(stackId)},
-              ${t.cloneNode(errorId)},
-              ${t.cloneNode(hasErrorId)},
-              // Pass SuppressedError so that it can be used with "pure"
-              // polyfills that do not compile the contents of runtime
-              // helpers.
-              typeof SuppressedError !== undefined && SuppressedError
-            );
+            ${disposeCall}
           }
         `;
 

diff --git a/...plugin-proposal-explicit-resource-management/test/fixtures/transform-await/mixed/input.js b/...plugin-proposal-explicit-resource-management/test/fixtures/transform-await/mixed/input.js
@@ -0,0 +1,5 @@
+{
+  using a = 1;
+  await using b = 2;
+  using c = 3;
+}
diff --git a/...ugin-proposal-explicit-resource-management/test/fixtures/transform-await/mixed/output.mjs b/...ugin-proposal-explicit-resource-management/test/fixtures/transform-await/mixed/output.mjs
@@ -0,0 +1,11 @@
+try {
+  var _stack = [];
+  const a = babelHelpers.using(_stack, 1);
+  const b = babelHelpers.using(_stack, 2, true);
+  const c = babelHelpers.using(_stack, 3);
+} catch (_) {
+  var _error = _;
+  var _hasError = true;
+} finally {
+  await babelHelpers.dispose(_stack, _error, _hasError, typeof SuppressedError !== undefined && SuppressedError);
+}
diff --git a/...osal-explicit-resource-management/test/fixtures/transform-await/only-using-await/input.js b/...osal-explicit-resource-management/test/fixtures/transform-await/only-using-await/input.js
@@ -0,0 +1,6 @@
+{
+  await using x = obj;
+  stmt;
+  await using y = obj, z = obj;
+  doSomethingWith(x, y);
+}
diff --git a/...al-explicit-resource-management/test/fixtures/transform-await/only-using-await/output.mjs b/...al-explicit-resource-management/test/fixtures/transform-await/only-using-await/output.mjs
@@ -0,0 +1,13 @@
+try {
+  var _stack = [];
+  const x = babelHelpers.using(_stack, obj, true);
+  stmt;
+  const y = babelHelpers.using(_stack, obj, true),
+    z = babelHelpers.using(_stack, obj, true);
+  doSomethingWith(x, y);
+} catch (_) {
+  var _error = _;
+  var _hasError = true;
+} finally {
+  await babelHelpers.dispose(_stack, _error, _hasError, typeof SuppressedError !== undefined && SuppressedError);
+}
diff --git a/...l-plugin-proposal-explicit-resource-management/test/fixtures/transform-await/options.json b/...l-plugin-proposal-explicit-resource-management/test/fixtures/transform-await/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["proposal-explicit-resource-management"]
+}