eslint-plugin-sonarjs
Version:
SonarJS rules for ESLint
237 lines (236 loc) • 11.1 kB
JavaScript
;
/*
* SonarQube JavaScript Plugin
* Copyright (C) 2011-2025 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the Sonar Source-Available License for more details.
*
* You should have received a copy of the Sonar Source-Available License
* along with this program; if not, see https://sonarsource.com/license/ssal/
*/
// https://sonarsource.github.io/rspec/#/rspec/S1226/javascript
Object.defineProperty(exports, "__esModule", { value: true });
exports.rule = void 0;
const index_js_1 = require("../helpers/index.js");
const meta_js_1 = require("./meta.js");
exports.rule = {
meta: (0, index_js_1.generateMeta)(meta_js_1.meta, {
messages: {
noReassignment: 'Introduce a new variable or use its initial value before reassigning "{{reference}}".',
},
}),
create(context) {
let variableUsageContext = {
type: 'global',
variablesToCheckInCurrentScope: new Set(),
variablesToCheck: new Set(),
variablesRead: new Set(),
referencesByIdentifier: new Map(),
};
function checkIdentifierUsage(identifier, identifierContextType) {
if (variableUsageContext.type !== identifierContextType) {
return;
}
const variableName = identifier.name;
const currentReference = getReference(variableUsageContext, identifier);
if (currentReference &&
!currentReference.init &&
!variableUsageContext.variablesRead.has(variableName)) {
if (variableUsageContext.variablesToCheck.has(variableName) &&
currentReference.isWriteOnly() &&
!isUsedInWriteExpression(variableName, currentReference.writeExpr)) {
// we do not raise issue when value is reassigned inside a top-level IfStatement, as it might be a shift or
// default value reassignment
if (isInsideIfStatement(context, identifier) ||
context.sourceCode.getAncestors(identifier).some(node => node.type === 'SwitchCase') // issue-2398
) {
return;
}
raiseIssue(currentReference);
}
markAsRead(variableUsageContext, variableName);
}
else if (variableName === 'arguments') {
markAllFunctionArgumentsAsRead(variableUsageContext);
}
}
function isUsedInWriteExpression(variableName, writeExpr) {
return (writeExpr &&
context.sourceCode.getFirstToken(writeExpr, token => token.value === variableName || token.value === 'arguments'));
}
function raiseIssue(reference) {
const locationHolder = getPreciseLocationHolder(reference);
context.report({
messageId: 'noReassignment',
data: {
reference: reference.identifier.name,
},
...locationHolder,
});
}
function popContext() {
variableUsageContext = variableUsageContext.parentContext
? variableUsageContext.parentContext
: variableUsageContext;
}
return {
onCodePathStart(_codePath, node) {
const currentScope = context.sourceCode.getScope(node);
if (currentScope && currentScope.type === 'function') {
const { referencesByIdentifier, variablesToCheck, variablesToCheckInCurrentScope } = computeNewContextInfo(variableUsageContext, context, node);
const functionName = getFunctionName(node);
if (functionName) {
variablesToCheck.delete(functionName);
}
variableUsageContext = {
type: 'function',
parentContext: variableUsageContext,
variablesToCheck,
referencesByIdentifier,
variablesToCheckInCurrentScope,
variablesRead: computeSetDifference(variableUsageContext.variablesRead, variablesToCheckInCurrentScope),
};
}
else {
variableUsageContext = {
type: 'global',
parentContext: variableUsageContext,
variablesToCheckInCurrentScope: new Set(),
variablesToCheck: new Set(),
variablesRead: new Set(),
referencesByIdentifier: new Map(),
};
}
},
onCodePathSegmentLoop(_fromSegment, _toSegment, node) {
const parent = (0, index_js_1.getParent)(context, node);
if (!isForEachLoopStart(node, parent)) {
return;
}
const currentScope = context.sourceCode.scopeManager.acquire(parent.body);
const { referencesByIdentifier, variablesToCheck, variablesToCheckInCurrentScope } = computeNewContextInfo(variableUsageContext, context, parent.left);
if (currentScope) {
for (const ref of currentScope.references) {
referencesByIdentifier.set(ref.identifier, ref);
}
}
// In case of array or object pattern expression, the left hand side are not declared variables but simply identifiers
(0, index_js_1.resolveIdentifiers)(parent.left, true)
.map(identifier => identifier.name)
.forEach(name => {
variablesToCheck.add(name);
variablesToCheckInCurrentScope.add(name);
});
variableUsageContext = {
type: 'foreach',
parentContext: variableUsageContext,
variablesToCheckInCurrentScope,
variablesToCheck,
variablesRead: computeSetDifference(variableUsageContext.variablesRead, variablesToCheckInCurrentScope),
referencesByIdentifier,
};
},
onCodePathSegmentStart(_segment, node) {
if (node.type !== 'CatchClause') {
return;
}
const { referencesByIdentifier, variablesToCheck, variablesToCheckInCurrentScope } = computeNewContextInfo(variableUsageContext, context, node);
variableUsageContext = {
type: 'catch',
parentContext: variableUsageContext,
variablesToCheckInCurrentScope,
variablesToCheck,
variablesRead: computeSetDifference(variableUsageContext.variablesRead, variablesToCheckInCurrentScope),
referencesByIdentifier,
};
},
onCodePathEnd: popContext,
'ForInStatement:exit': popContext,
'ForOfStatement:exit': popContext,
'CatchClause:exit': popContext,
'*:function > BlockStatement Identifier': (node) => checkIdentifierUsage(node, 'function'),
'ForInStatement > *:statement Identifier': (node) => checkIdentifierUsage(node, 'foreach'),
'ForOfStatement > *:statement Identifier': (node) => checkIdentifierUsage(node, 'foreach'),
'CatchClause > BlockStatement Identifier': (node) => checkIdentifierUsage(node, 'catch'),
};
},
};
function isInsideIfStatement(context, node) {
const ancestors = context.sourceCode.getAncestors(node);
for (let i = ancestors.length - 1; i >= 0; i--) {
if (ancestors[i].type === 'IfStatement' &&
// We check if the consequent or the alternate are also ancestors
// Nodes in the test attribute should be raised
i < ancestors.length - 1 &&
(ancestors[i + 1] === ancestors[i].consequent ||
ancestors[i + 1] === ancestors[i].alternate)) {
return true;
}
}
return false;
}
/**
* Computes the set difference (a \ b)
*/
function computeSetDifference(a, b) {
return new Set([...a].filter(str => !b.has(str)));
}
function getFunctionName(node) {
return !node.id ? null : node.id.name;
}
function isForEachLoopStart(node, parent) {
return (node.type === 'BlockStatement' &&
!!parent &&
(parent.type === 'ForInStatement' || parent.type === 'ForOfStatement'));
}
function computeNewContextInfo(variableUsageContext, context, node) {
const referencesByIdentifier = new Map();
const variablesToCheck = new Set(variableUsageContext.variablesToCheck);
const variablesToCheckInCurrentScope = new Set();
context.sourceCode.getDeclaredVariables(node).forEach(variable => {
variablesToCheck.add(variable.name);
variablesToCheckInCurrentScope.add(variable.name);
for (const currentRef of variable.references) {
referencesByIdentifier.set(currentRef.identifier, currentRef);
}
});
return { referencesByIdentifier, variablesToCheck, variablesToCheckInCurrentScope };
}
function markAsRead(context, variableName) {
context.variablesRead.add(variableName);
if (!context.variablesToCheckInCurrentScope.has(variableName) && context.parentContext) {
markAsRead(context.parentContext, variableName);
}
}
function markAllFunctionArgumentsAsRead(variableUsageContext) {
let functionContext = variableUsageContext;
while (functionContext && functionContext.type !== 'function') {
functionContext = functionContext.parentContext;
}
if (functionContext) {
for (const variableName of functionContext.variablesToCheckInCurrentScope) {
functionContext.variablesRead.add(variableName);
}
}
}
function getPreciseLocationHolder(reference) {
const identifierLoc = reference.identifier.loc;
if (identifierLoc && reference.writeExpr && reference.writeExpr.loc) {
return { loc: { start: identifierLoc.start, end: reference.writeExpr.loc.end } };
}
return { node: reference.identifier };
}
function getReference(variableUsageContext, identifier) {
const identifierReference = variableUsageContext.referencesByIdentifier.get(identifier);
if (!identifierReference && variableUsageContext.parentContext) {
return getReference(variableUsageContext.parentContext, identifier);
}
return identifierReference;
}