packageFilter paths should be realpathed with preserveSymlinks: false

[bterlson]

Right now a package filter is called with potentially symlinked paths.

[ljharb]

Thanks! I'll take a look, but a PR with a test case would be super helpful.

[bterlson]

@ljharb will try to put up a PR, but test cases are really annoying to make when symlinking is involved. Here's how to repro, though:

Directory structure like:

common
  node_modules
    mod-a
project
  node_modules
    mod-a -> ..\..\common\node_modules\mod-a

cd into project, open a node console, and enter:

> require('resolve').sync('mod-a', {
    preserveSymlinks: false,
    packageFilter (_, path) { console.log(path) }
  });
// console logs a symlinked path for the package json, but returns a realpath as expected.

[ljharb]

@bterlson in your example, there's no package.jsons - packageFilter only kicks in when there is one. Do you also have a package.json inside mod-a?

[bterlson]

@ljharb yessir, and main files, although that part is probably not necessary to highlight the problem.

[ljharb]

Writing this failing test exposed two more unrelated bugs (#202 covers one of them) that I'll need to test and fix separately :-) This one's coming up shortly tho!

[ljharb]

v1.12.1 v1.12.2 is released.

Note that this includes a bugfix where packageFilter was incorrectly getting called with the documented 2nd arg omitted; any sync packageFilter callbacks will likely need to be altered.