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Allow duplicate __proto__ keys in patterns, simple case (babel#6705)
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@alejo90
alejo90 committed Oct 9, 2019
1 parent c7add11 commit fab52c9
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Showing 4 changed files with 230 additions and 15 deletions.
25 changes: 15 additions & 10 deletions packages/babel-parser/src/parser/expression.js
View file
Expand Up @@ -67,14 +67,13 @@ export default class ExpressionParser extends LValParser {
+parseFunctionParams: (node: N.Function, allowModifiers?: boolean) => void;
+takeDecorators: (node: N.HasDecorators) => void;

// Check if property name clashes with already added.
// Object/class getters and setters are not allowed to clash —
// either with each other or with an init property — and in
// strict mode, init properties are also not allowed to be repeated.
// Check if property __proto__ has been used more than once.
// If the expression is a destructuring assignment, then __proto__ may appear
// multiple times. Otherwise, __proto__ is a duplicated key.

checkPropClash(
checkDuplicatedProto(
prop: N.ObjectMember | N.SpreadElement,
propHash: { [key: string]: boolean },
propHash: { [key: string]: number },
): void {
if (
prop.type === "SpreadElement" ||
Expand All @@ -91,10 +90,12 @@ export default class ExpressionParser extends LValParser {
const name = key.type === "Identifier" ? key.name : String(key.value);

if (name === "__proto__") {
if (propHash.proto) {
this.raise(key.start, "Redefinition of __proto__ property");
propHash.proto = (propHash.proto || 0) + 1;

// Store the first redefinition's position
if (propHash.proto === 2) {
propHash.protoStart = key.start;
}
propHash.proto = true;
}
}

Expand Down Expand Up @@ -1509,7 +1510,7 @@ export default class ExpressionParser extends LValParser {

const prop = this.parseObjectMember(isPattern, refShorthandDefaultPos);
// $FlowIgnore RestElement will never be returned if !isPattern
if (!isPattern) this.checkPropClash(prop, propHash);
if (!isPattern) this.checkDuplicatedProto(prop, propHash);

// $FlowIgnore
if (prop.shorthand) {
Expand All @@ -1519,6 +1520,10 @@ export default class ExpressionParser extends LValParser {
node.properties.push(prop);
}

if (!this.match(tt.eq) && propHash.protoStart !== undefined) {
this.raise(propHash.protoStart, "Redefinition of __proto__ property");
}

return this.finishNode(
node,
isPattern ? "ObjectPattern" : "ObjectExpression",
Expand Down
12 changes: 7 additions & 5 deletions packages/babel-parser/src/plugins/estree.js
View file
Expand Up @@ -125,9 +125,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
}
}

checkPropClash(
checkDuplicatedProto(
prop: N.ObjectMember | N.SpreadElement,
propHash: { [key: string]: boolean },
propHash: { [key: string]: number },
): void {
if (
prop.type === "SpreadElement" ||
Expand All @@ -144,10 +144,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
const name = key.type === "Identifier" ? key.name : String(key.value);

if (name === "__proto__" && prop.kind === "init") {
if (propHash.proto) {
this.raise(key.start, "Redefinition of __proto__ property");
propHash.proto = (propHash.proto || 0) + 1;

// Store the first redefinition's position
if (propHash.proto === 2) {
propHash.protoStart = key.start;
}
propHash.proto = true;
}
}

Expand Down
1 change: 1 addition & 0 deletions packages/babel-parser/test/fixtures/es2015/destructuring/duplicate-proto/input.js
View file
@@ -0,0 +1 @@
({ __proto__: x, __proto__: y } = {});
207 changes: 207 additions & 0 deletions packages/babel-parser/test/fixtures/es2015/destructuring/duplicate-proto/output.json
View file
@@ -0,0 +1,207 @@
{
"type": "File",
"start": 0,
"end": 38,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 38
}
},
"program": {
"type": "Program",
"start": 0,
"end": 38,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 38
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "ExpressionStatement",
"start": 0,
"end": 38,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 38
}
},
"expression": {
"type": "AssignmentExpression",
"start": 1,
"end": 36,
"loc": {
"start": {
"line": 1,
"column": 1
},
"end": {
"line": 1,
"column": 36
}
},
"operator": "=",
"left": {
"type": "ObjectPattern",
"start": 1,
"end": 31,
"loc": {
"start": {
"line": 1,
"column": 1
},
"end": {
"line": 1,
"column": 31
}
},
"properties": [
{
"type": "ObjectProperty",
"start": 3,
"end": 15,
"loc": {
"start": {
"line": 1,
"column": 3
},
"end": {
"line": 1,
"column": 15
}
},
"method": false,
"key": {
"type": "Identifier",
"start": 3,
"end": 12,
"loc": {
"start": {
"line": 1,
"column": 3
},
"end": {
"line": 1,
"column": 12
},
"identifierName": "__proto__"
},
"name": "__proto__"
},
"computed": false,
"shorthand": false,
"value": {
"type": "Identifier",
"start": 14,
"end": 15,
"loc": {
"start": {
"line": 1,
"column": 14
},
"end": {
"line": 1,
"column": 15
},
"identifierName": "x"
},
"name": "x"
}
},
{
"type": "ObjectProperty",
"start": 17,
"end": 29,
"loc": {
"start": {
"line": 1,
"column": 17
},
"end": {
"line": 1,
"column": 29
}
},
"method": false,
"key": {
"type": "Identifier",
"start": 17,
"end": 26,
"loc": {
"start": {
"line": 1,
"column": 17
},
"end": {
"line": 1,
"column": 26
},
"identifierName": "__proto__"
},
"name": "__proto__"
},
"computed": false,
"shorthand": false,
"value": {
"type": "Identifier",
"start": 28,
"end": 29,
"loc": {
"start": {
"line": 1,
"column": 28
},
"end": {
"line": 1,
"column": 29
},
"identifierName": "y"
},
"name": "y"
}
}
]
},
"right": {
"type": "ObjectExpression",
"start": 34,
"end": 36,
"loc": {
"start": {
"line": 1,
"column": 34
},
"end": {
"line": 1,
"column": 36
}
},
"properties": []
},
"extra": {
"parenthesized": true,
"parenStart": 0
}
}
}
],
"directives": []
}
}

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