Parcel: Similar Files are collapsed (breaking react-bootstrap)

[killroy42]

🐛 bug report

When two different modules contain the same code, they are collapsed such that the code does not get executed as required.

For example, react-bootstrap contains two files with this content:

import React from 'react';
export default React.createContext(null);

With parcel, these "two modules" actually execute only once and return the same value. If I add some comment to one (e.g. //) it works as expected.

🎛 Configuration (.babelrc, package.json, cli command)

Running parcel with:

parcel --no-cache ./src/index.html --public-url=/reacttest --no-hmr

🤔 Expected Behavior

Perhaps the code could be collapsed for space saving purposes, but it still needs to be executed individually.

😯 Current Behavior

Similar files are merged and eliminated and executed only once.

💁 Possible Solution

Ideally do not eliminate similar files, or ensure they are executed individually.

🔦 Context

This breaks basic behavior in react-bootstrap related to CardContext and AccordionContext.

[mischnic]

A duplicate of #3368.

[wojtekmaj]

I think it's severe enough to deserve a fix on 1.x branch.

[mischnic]

(The relevant function:
https://github.com/parcel-bundler/parcel/blob/fe08980a6f256d94100d017e7c1f1e0b3a527ec0/packages/core/parcel-bundler/src/Asset.js#L227-L229
this.name or this.relativeName could also be factored in
)

[kalda341]

Agreed that this is worth fixing on 1.x. This issue has cost me several days in troubleshooting.