CommonJS: symbol not renamed in inline module.exports assignment

[blutorange]

java -jar closure-compiler-v20191027.jar --version
Closure Compiler (http://github.com/google/closure-compiler)
Version: v20191027
Built on: 2019-10-30 03:56

Came across this when running closure compiler on core-js, caused by this file: zloirock/core-js/internal-metadata.js. It contains a module.exports assignment within a compound assignment (see at the bottom).

Possibly related to #3093 ?

Minimal example that reproduces this:

// /tmp/export-wrong.js
var exp = () => {};
var meta = module.exports = {exp: exp}

This currently compiles to:

java -jar closure-compiler-v20191027.jar --process_common_js_modules=true --entry_point=/tmp/exports-wrong.js  --compilation_level=SIMPLE_OPTIMIZATIONS --js /tmp/exports-wrong.js

var module$tmp$exports_wrong={default:{}};
module$tmp$exports_wrong.default.exp=function(){};
var meta$$module$tmp$exports_wrong=module$tmp$exports_wrong.default={exp:exp};

Are these kind of exports supported? When this code is run, exp will be undefined. It works correctly when changing the export to a top-level assignment statement:

var exp = () => {};
var meta = {exp: exp};
module.exports = meta;

[mprobst]

Created internal issue b/144257170.

[mprobst]

@ChadKillingsworth maybe something for you?

[brad4d]

FWIW, if you try to write similar code when using goog.module() you get an error that stops compilation.

https://closure-compiler-debugger.appspot.com/#input0%3Dgoog.module('foo')%253B%250A%250Aconst%2520exp%2520%253D%2520()%2520%253D%253E%2520%257B%257D%253B%250Aconst%2520meta%2520%253D%2520exports%2520%253D%2520%257Bexp%253Aexp%2520%257D%253B%250A%26input1%26conformanceConfig%26externs%26refasterjs-template%26includeDefaultExterns%3Dtrue%26CHECK_TYPES%3Dtrue%26REWRITE_MODULES_BEFORE_TYPECHECKING%3Dtrue%26TRANSPILE%3Dtrue%26CLOSURE_PASS%3Dtrue%26PRESERVE_TYPE_ANNOTATIONS%3Dtrue%26PRETTY_PRINT%3Dtrue

It seems likely that the code for handling CommonJS modules should do something similar.