v7 breaks sinon stubbing

[hldswrth]

We use sinon in our (common JS) unit tests for code which uses the tar.x function. This work fine with v6.

const tar = require('tar')
const sinon = require('sinon')
const tarXStub = sinon.stub(tar, 'x')
.. run test for code which calls the x function...
tarXstub.restore()

When using v7 with no other changes to our code or tests, the tests which involve the x function fail with error TAR_BAD_ARCHIVE: Unrecognized archive format which indicates the stubbing is not effective, despite the sinon.stub and sinon.restore calls appearing to be successful.

[AviVahl]

x is now a getter, because the codebase uses typescript and native esm, and live bindings need to work (even when transpiled to commonjs).

possible workarounds:

• require('tar/extract') directly in your code and mock the extract method.
• mock the fn on your end that calls tar.

[hldswrth]

Thanks for the quick response. I did try changing my code to call tar.extract insted of tar.x but this cannot be stubbed by sinon, doing a sinon.stub(tar, 'extract') results in TypeError: Descriptor for property extract is non-configurable and non-writable.
If I require('tar/extract') I don't see how I would stub that with sinon.

[AviVahl]

Rather than requiring tar in the implementation, require tar/extract and use the extract fn exported from that module.

Do the same where you mock. That module directly exports the fn extract, meaning it can be mocked, as it's not a getter.

[hldswrth]

Thanks! The following does appear to at least pass unit tests again:

// code:
const extract = require('tar/extract')
return extract.extract(options)

// test:
const extract = require('tar/extract')
const extractStub = sinon.stub(extract, 'extract')