Fix location of temporary hard links of index.json

[nehaljwani]

The command:
$ conda install https://repo.continuum.io/pkgs/free/linux-64/affine-1.1.0-py27_0.tar.bz2 --debug

Reveals:
DEBUG conda.common.disk:rm_rf(198): rm_rf /home/wani/conda/.tmp-affine-1.1.0-py27_0

The command:
$ conda install /tmp/affine-1.1.0-py27_0.tar.bz2 --debug

Reveals:
DEBUG conda.common.disk:rm_rf(198): rm_rf /home/wani/conda/file:/tmp::/.tmp-affine-1.1.0-py27_0

As is evident, when the protocol is file://, conda creates a bogus
folder by the name: file:/ + /path/to/folder/of/tar.gz + '::'

The variable 'prefix' is required by the function try_hard_link().
We shouldn't modify it before that. This change ensures that the
file ${prefix}/.tmp-${pkgname} is indeed created inside the folder
${prefix}.

Fixes #3801

[kalefranz]

I think I'm missing something here. I think you've debugged the problem correctly in your description, but all I can tell from the PR is that you've renamed prefix to url_prefix. Is there a logic change I'm missing?

[kalefranz]

Appreciate the work on this btw. This has been an annoying bug that I just haven't had time to track down. It was easier to write the clean-all target in the Makefile 😬

[nehaljwani]

@kalefranz The rename itself fixes the issue.
In the code, the function explicit() calls try_hard_link() near the end. Since try_hard_link() expects the parameter prefix, we should make sure that it is passed as such, un-modified. Without this patch, the variable prefix gets modified to 'file://tmp::' which is not expected. Hence, I use a different variable url_prefix to hold the url prefix.

[kalefranz]

👍

[github-actions]

Hi there, thank you for your contribution to Conda!

This pull request has been automatically locked since it has not had recent activity after it was closed.

Please open a new issue or pull request if needed.