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Fix tdz checks in transform-block-scoping plugin (#9498)

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* Better tdz tests

- Use jest's expect.toThrow/expect.not.toThrow
- Add input/output tests

* Fix basic tdz (a = 2; let a)

Fixes #6848

* Make _guessExecutionStatusRelativeTo more robust

* Add tests

* Return less "unkown" execution status

* "function" execution status does not exist

* Fix recursive functions

* Update helper version

* "finally" blocks are always executed

* Typo
This commit is contained in:
Nicolò Ribaudo
2019-07-21 06:34:43 +02:00
committed by GitHub
parent 9bc9571381
commit fced5cea43
65 changed files with 507 additions and 122 deletions
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18
packages/babel-plugin-transform-block-scoping/src/index.js
View File

@@ -16,7 +16,7 @@ export default declare((api, opts) => {
throw new Error(`.throwIfClosureRequired must be a boolean, or undefined`);
}
if (typeof tdzEnabled !== "boolean") {
throw new Error(`.throwIfClosureRequired must be a boolean, or undefined`);
throw new Error(`.tdz must be a boolean, or undefined`);
}
return {
@@ -33,11 +33,13 @@ export default declare((api, opts) => {
for (let i = 0; i < node.declarations.length; i++) {
const decl = node.declarations[i];
if (decl.init) {
const assign = t.assignmentExpression("=", decl.id, decl.init);
assign._ignoreBlockScopingTDZ = true;
nodes.push(t.expressionStatement(assign));
}
const assign = t.assignmentExpression(
"=",
decl.id,
decl.init || scope.buildUndefinedNode(),
);
assign._ignoreBlockScopingTDZ = true;
nodes.push(t.expressionStatement(assign));
decl.init = this.addHelper("temporalUndefined");
}
@@ -181,6 +183,8 @@ const letReferenceBlockVisitor = traverse.visitors.merge([
// simply rename the variables.
if (state.loopDepth > 0) {
path.traverse(letReferenceFunctionVisitor, state);
} else {
path.traverse(tdzVisitor, state);
}
return path.skip();
},
@@ -756,7 +760,7 @@ class BlockScoping {
closurify: false,
loopDepth: 0,
tdzEnabled: this.tdzEnabled,
addHelper: name => this.addHelper(name),
addHelper: name => this.state.addHelper(name),
};
if (isInLoop(this.blockPath)) {

27
packages/babel-plugin-transform-block-scoping/src/tdz.js
View File

@@ -1,12 +1,12 @@
import { types as t } from "@babel/core";
import { types as t, template } from "@babel/core";
function getTDZStatus(refPath, bindingPath) {
const executionStatus = bindingPath._guessExecutionStatusRelativeTo(refPath);
if (executionStatus === "before") {
return "inside";
} else if (executionStatus === "after") {
return "outside";
} else if (executionStatus === "after") {
return "inside";
} else {
return "maybe";
}
@@ -41,7 +41,7 @@ export const visitor = {
if (bindingPath.isFunctionDeclaration()) return;
const status = getTDZStatus(path, bindingPath);
if (status === "inside") return;
if (status === "outside") return;
if (status === "maybe") {
const assert = buildTDZAssert(node, state);
@@ -57,19 +57,8 @@ export const visitor = {
} else {
path.replaceWith(assert);
}
} else if (status === "outside") {
path.replaceWith(
t.throwStatement(
t.inherits(
t.newExpression(t.identifier("ReferenceError"), [
t.stringLiteral(
`${node.name} is not defined - temporal dead zone`,
),
]),
node,
),
),
);
} else if (status === "inside") {
path.replaceWith(template.ast`${state.addHelper("tdz")}("${node.name}")`);
}
},
@@ -87,14 +76,14 @@ export const visitor = {
const id = ids[name];
if (isReference(id, path.scope, state)) {
nodes.push(buildTDZAssert(id, state));
nodes.push(id);
}
}
if (nodes.length) {
node._ignoreBlockScopingTDZ = true;
nodes.push(node);
path.replaceWithMultiple(nodes.map(t.expressionStatement));
path.replaceWithMultiple(nodes.map(n => t.expressionStatement(n)));
}
},
},