[commonjs] Undeclared value gets exported

[bpierre]

• Rollup Plugin Name: commonjs
• Rollup Plugin Version: 14.0.0
• Rollup Version: 2.23.0
• Operating System (or Browser): Linux
• Node Version: 13.7.0
• Link to reproduction: https://gist.github.com/bpierre/981a9c9d79adc32f06c4bcf9fef3962c

How to reproduce:

git clone git@gist.github.com:981a9c9d79adc32f06c4bcf9fef3962c.git
cd 981a9c9d79adc32f06c4bcf9fef3962c
yarn && yarn rollup -c
cat dist/981a9c9d79adc32f06c4bcf9fef3962c/node_modules/@walletconnect/web3-provider/dist/cjs/index.js

Expected Behavior

The last line of the output shouldn’t contain index as i:

// …
export { cjs as __moduleExports };

Actual Behavior

An non-declared value, index, gets exported:

// …
export { cjs as __moduleExports, index as i };

[shellscape]

Thanks for opening an issue. Citing the issue template:

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Please provide one by:

1. Using the REPL.it plugin reproduction template at https://repl.it/@rollup/rollup-plugin-repro
2. Provide a minimal repository link (Read https://git.io/fNzHA for instructions).
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We cannot make this any clearer. Please add a valid reproduction from the list above and we'll be happy to triage further.

[shellscape]

Hey sorry, the script got ya. It doesn't recognize a gist as a repo. It's a little unorthodox, but no worries.

[lukastaegert]

It appears that this is a bug in Rollup core that is triggered by dynamically importing a file with synthetic named exports: https://repl.it/@lukastaegert/rollup-plugin-repro-1#dist/lib.js

[lukastaegert]

Fix at rollup/rollup#3738