Mark renamed paths in mangler (#390)

The issue was renaming an already renamed path. Maybe something quircky about bindings of destructuring assingments in babel.

+ (Fix #326)
+ (Fix #369)

packages/babel-plugin-minify-mangle-names/__tests__/mangle-names-test.js

@@ -1067,4 +1067,42 @@ describe("mangle-names", () => {
 
     expect(transform(source, { topLevel: true })).toBe(expected);
   });
+
+  it("should fix #326, #369 - destructuring", () => {
+    const source = unpad(`
+      // issue#326
+      function a() {
+        let foo, bar, baz;
+        ({foo, bar, baz} = {});
+        return {foo, bar, baz};
+      }
+      // issue#369
+      function decodeMessage(message){
+        let namespace;
+        let name;
+        let value = null;
+
+        [, namespace, name, value] = message.split(',') || [];
+        console.log(name);
+      }
+    `);
+    const expected = unpad(`
+      // issue#326
+      function a() {
+        let b, c, d;
+        ({ foo: b, bar: c, baz: d } = {});
+        return { foo: b, bar: c, baz: d };
+      }
+      // issue#369
+      function decodeMessage(b) {
+        let c;
+        let d;
+        let e = null;
+
+        [, c, d, e] = b.split(\',\') || [];
+        console.log(d);
+      }
+    `);
+    expect(transform(source)).toBe(expected);
+  });
 });

packages/babel-plugin-minify-mangle-names/src/index.js

@@ -6,6 +6,8 @@ const {
   hasEval,
 } = require("babel-helper-mark-eval-scopes");
 
+const PATH_RENAME_MARKER = Symbol("PATH_RENAME_MARKER");
+
 module.exports = ({ types: t, traverse }) => {
   const hop = Object.prototype.hasOwnProperty;
 
@@ -181,7 +183,16 @@ module.exports = ({ types: t, traverse }) => {
       const binding = scope.getBinding(oldName);
 
       // rename at the declaration level
-      binding.identifier.name = newName;
+      const bindingPaths = binding.path.getBindingIdentifierPaths();
+
+      Object
+        .keys(bindingPaths)
+        .map((b) => {
+          if (b === oldName && !bindingPaths[b][PATH_RENAME_MARKER]) {
+            bindingPaths[b].replaceWith(t.identifier(newName));
+            bindingPaths[b][PATH_RENAME_MARKER] = true;
+          }
+        });
 
       const {bindings} = scope;
       bindings[newName] = binding;
@@ -192,18 +203,23 @@ module.exports = ({ types: t, traverse }) => {
       for (let i = 0; i < violations.length; i++) {
         if (violations[i].isLabeledStatement()) continue;
 
-        const bindings = violations[i].getBindingIdentifiers();
+        const bindings = violations[i].getBindingIdentifierPaths();
         Object
           .keys(bindings)
           .map((b) => {
-            bindings[b].name = newName;
+            if (b === oldName && !bindings[b][PATH_RENAME_MARKER]) {
+              bindings[b].replaceWith(t.identifier(newName));
+              bindings[b][PATH_RENAME_MARKER] = true;
+            }
           });
       }
 
       // update all referenced places
       const refs = binding.referencePaths;
       for (let i = 0; i < refs.length; i++) {
         const path = refs[i];
+        if (path[PATH_RENAME_MARKER]) continue;
+
         const {node} = path;
         if (!path.isIdentifier()) {
           // Ideally, this should not happen
@@ -216,7 +232,7 @@ module.exports = ({ types: t, traverse }) => {
           // replacement in dce from `x` to `!x` gives referencePath as `!x`
           path.traverse({
             ReferencedIdentifier(refPath) {
-              if (refPath.node.name === oldName && refPath.scope === scope) {
+              if (refPath.node.name === oldName && refPath.scope === scope && !refPath[PATH_RENAME_MARKER]) {
                 refPath.node.name = newName;
               }
             }