Update: Improve parser integrations (fixes #8392)

lib/linter.js

@@ -43,6 +43,8 @@ const MAX_AUTOFIX_PASSES = 10;
  * @property {ASTNode} ast The ESTree AST Program node.
  * @property {Object} services An object containing additional services related
  *      to the parser.
+ * @property {ScopeManager|null} scope The scope of this AST.
+ * @property {Object|null} visitorKeys The visitor keys to traverse this AST.
  */
 
 //------------------------------------------------------------------------------
@@ -763,9 +765,7 @@ class Linter extends EventEmitter {
      */
     verify(textOrSourceCode, config, filenameOrOptions, saveState) {
         const text = (typeof textOrSourceCode === "string") ? textOrSourceCode : null;
-        let ast,
-            parseResult,
-            allowInlineConfig;
+        let allowInlineConfig;
 
         // evaluate arguments
         if (typeof filenameOrOptions === "object") {
@@ -805,7 +805,7 @@ class Linter extends EventEmitter {
                 return this.messages;
             }
 
-            parseResult = parse(
+            const parseResult = parse(
                 stripUnicodeBOM(text).replace(astUtils.SHEBANG_MATCHER, (match, captured) => `//${captured}`),
                 config,
                 this.currentFilename,
@@ -814,27 +814,35 @@ class Linter extends EventEmitter {
 
             // if this result is from a parseForESLint() method, normalize
             if (parseResult && parseResult.ast) {
-                ast = parseResult.ast;
-            } else {
-                ast = parseResult;
-                parseResult = null;
-            }
 
-            if (ast) {
-                this.sourceCode = new SourceCode(text, ast);
+                // Save all returned values of `parse()` because this source code object can be reused.
+                // This ensures the same result when reused.
+                this.sourceCode = new SourceCode(
+                    text,
+                    parseResult.ast,
+                    parseResult.services,
+                    parseResult.scope,
+                    parseResult.visitorKeys
+                );
+            } else if (parseResult) {
+                this.sourceCode = new SourceCode(
+                    text,
+                    parseResult
+                );
+            } else {
+                this.sourceCode = null;
             }
 
         } else {
             this.sourceCode = textOrSourceCode;
-            ast = this.sourceCode.ast;
         }
 
         // if espree failed to parse the file, there's no sense in setting up rules
-        if (ast) {
+        if (this.sourceCode) {
 
             // parse global comments and modify config
             if (allowInlineConfig !== false) {
-                config = modifyConfigsFromComments(this.currentFilename, ast, config, this);
+                config = modifyConfigsFromComments(this.currentFilename, this.sourceCode.ast, config, this);
             }
 
             // ensure that severities are normalized in the config
@@ -865,7 +873,7 @@ class Linter extends EventEmitter {
                         key, this, severity, options,
                         config.settings, config.parserOptions, config.parser,
                         ruleCreator.meta,
-                        (parseResult && parseResult.services ? parseResult.services : {})
+                        this.sourceCode.parserServices || {}
                     );
 
                     const rule = ruleCreator.create ? ruleCreator.create(ruleContext)
@@ -890,21 +898,25 @@ class Linter extends EventEmitter {
 
             const ecmaFeatures = this.currentConfig.parserOptions.ecmaFeatures || {};
             const ecmaVersion = this.currentConfig.parserOptions.ecmaVersion || 5;
+            const sourceType = this.currentConfig.parserOptions.sourceType || "script";
 
             // gather scope data that may be needed by the rules
-            this.scopeManager = eslintScope.analyze(ast, {
-                ignoreEval: true,
-                nodejsScope: ecmaFeatures.globalReturn,
-                impliedStrict: ecmaFeatures.impliedStrict,
-                ecmaVersion,
-                sourceType: this.currentConfig.parserOptions.sourceType || "script",
-                fallback: Traverser.getKeys
-            });
+            this.scopeManager =
+                this.sourceCode.scopeManager ||
+                eslintScope.analyze(this.sourceCode.ast, {
+                    ignoreEval: true,
+                    nodejsScope: ecmaFeatures.globalReturn,
+                    impliedStrict: ecmaFeatures.impliedStrict,
+                    ecmaVersion,
+                    sourceType,
+                    fallback: Traverser.getKeys,
+                    childVisitorKeys: this.sourceCode.visitorKeys || Traverser.DEFAULT_VISITOR_KEYS
+                });
 
             this.currentScopes = this.scopeManager.scopes;
 
             // augment global scope with declared global variables
-            addDeclaredGlobals(ast, this.currentScopes[0], this.currentConfig, this.environments);
+            addDeclaredGlobals(this.sourceCode.ast, this.currentScopes[0], this.currentConfig, this.environments);
 
             let eventGenerator = new NodeEventGenerator(this);
 
@@ -916,7 +928,8 @@ class Linter extends EventEmitter {
              * automatically be informed that this type of node has been found
              * and react accordingly.
              */
-            this.traverser.traverse(ast, {
+            this.traverser.traverse(this.sourceCode.ast, {
+                keys: this.sourceCode.visitorKeys,
                 enter(node, parent) {
                     node.parent = parent;
                     eventGenerator.enterNode(node);

lib/rules/no-unmodified-loop-condition.js

@@ -111,13 +111,14 @@ const isInLoop = {
  *
  * @param {ASTNode} root - A node to check.
  *      This node is one of BinaryExpression or ConditionalExpression.
+ * @param {SourceCode} sourceCode - The source code object of this context.
  * @returns {boolean} `true` if the node is dynamic.
  */
-function hasDynamicExpressions(root) {
+function hasDynamicExpressions(root, sourceCode) {
     let retv = false;
-    const traverser = new Traverser();
 
-    traverser.traverse(root, {
+    Traverser.traverse(root, {
+        keys: sourceCode.visitorKeys,
         enter(node) {
             if (DYNAMIC_PATTERN.test(node.type)) {
                 retv = true;
@@ -135,9 +136,10 @@ function hasDynamicExpressions(root) {
  * Creates the loop condition information from a given reference.
  *
  * @param {eslint-scope.Reference} reference - A reference to create.
+ * @param {SourceCode} sourceCode - The source code object of this context.
  * @returns {LoopConditionInfo|null} Created loop condition info, or null.
  */
-function toLoopCondition(reference) {
+function toLoopCondition(reference, sourceCode) {
     if (reference.init) {
         return null;
     }
@@ -170,7 +172,7 @@ function toLoopCondition(reference) {
         if (GROUP_PATTERN.test(node.type)) {
 
             // If this expression is dynamic, no need to check.
-            if (hasDynamicExpressions(node)) {
+            if (hasDynamicExpressions(node, sourceCode)) {
                 break;
             } else {
                 group = node;
@@ -254,6 +256,7 @@ module.exports = {
     },
 
     create(context) {
+        const sourceCode = context.getSourceCode();
         let groupMap = null;
 
         /**
@@ -319,7 +322,7 @@ module.exports = {
             // Gets references that exist in loop conditions.
             const conditions = variable
                 .references
-                .map(toLoopCondition)
+                .map(reference => toLoopCondition(reference, sourceCode))
                 .filter(Boolean);
 
             if (conditions.length === 0) {