fs.cp/fs.cpSync convert relative symlinks to absolute symlinks

[marcosbc]

Version

v16.13.2

Platform

Linux mbdev 4.15.0-142-generic #146~16.04.1-Ubuntu SMP Tue Apr 13 09:27:15 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

Create the following folder structure (see example code below):

.
├── test1
│   ├── bar -> foo
│   └── foo
└── test2

This can be achieved with the following commands:

$ mkdir test1 test2
$ touch test1/foo
$ ln -s foo test1/bar

Afterwards, execute the following command in your Node.js console:

$ fs.cpSync('test1', 'test2', {recursive: true});

How often does it reproduce? Is there a required condition?

This happens in all Node.js releases from 16.7.0, where fs.cp and fs.cpSync are supported.

What is the expected behavior?

Given the above example, it would be expected for the test2 folder to contain a relative symlink bar, same than test1, since the action is expected to replicate the entire structure from one folder to another, i.e.:

.
├── test1
│   ├── bar -> foo
│   └── foo
└── test2
    ├── bar -> foo
    └── foo

What do you see instead?

Given the above example, the symlinks are converted to absolute symlinks, and also pointing to the "previous" path, i.e.:

.
├── test1
│   ├── bar -> foo
│   └── foo
└── test2
    ├── bar -> /tmp/nodejs-cp-error/test1/foo
    └── foo

Additional information

No response

[tniessen]

.
├── foo
|   ├── target
│   ├── copy_me
│       ├── somelink -> ../target
└── bar
    ├── copy_here

To clarify, what should be the result of copying copy_me to copy_here? Should bar/copy_here/somelink point to ../../foo/target? What if foo and bar are on different Windows drives and no relative path exists that could refer to the original link?

[marcosbc]

@tniessen I agree that in this case it would not make sense. In our case, we were finding issues because we were distributing a folder created as a result of cpSync, but not the "origin" folder there the files were copied from, so some symlinks would point to the "origin" paths that were not available.

I sent a proposal in #41819 to implement this feature, which could be enabled by passing absolute: false verbatimSymlinks: true to fs.cp or fs.cpSync. In order not to break existing code, I proposed disabling it by default.

[tniessen]

I am going to mark this as a feature request, not a bug, then.