Prevent parseForESLint() behavior from changing after parse() is called

(fixes #558, fixes eslint/eslint#9767)

Author: not-an-aardvark

lib/index.js

@@ -1,18 +1,14 @@
 "use strict";
 
-let patched = false;
-
 exports.parse = function(code, options) {
-  patched = true;
   return require("./parse-with-patch")(code, options);
 };
 
 exports.parseForESLint = function(code, options) {
-  if (!patched && options.eslintVisitorKeys && options.eslintScopeManager) {
+  if (options.eslintVisitorKeys && options.eslintScopeManager) {
     return require("./parse-with-scope")(code, options);
   }
 
-  patched = true;
   return { ast: require("./parse-with-patch")(code, options) };
 };
 

test/babel-eslint.js

@@ -539,4 +539,16 @@ describe("Public API", () => {
       babelEslint.parseNoPatch("foo", {})
     );
   });
+
+  it("still provides a custom scope with parseForESLint after calling parse()", () => {
+    assertImplementsAST(
+      espree.parse("foo", { sourceType: "module" }),
+      babelEslint.parse("foo", {})
+    );
+    const parseForESLintResult = babelEslint.parseForESLint("foo", {
+      eslintVisitorKeys: true,
+      eslintScopeManager: true,
+    });
+    assert(parseForESLintResult.visitorKeys);
+  });
 });