Add the possibility to follow symlinks on copytree also for py3

[alquerci]

Hello,

Reply to #1311

It's an answer of https://github.com/pypa/pip/pull/1311/files#r7640350

If a project contains true NTFS symlinks it require elevated privileges indeed (source: @docs.python: os.symlink and @wikipedia: NTFS_symbolic_link)

• Fix shutil.copytree for py3 when a symlink points to a directory
• Prevent circular symbolic links
• Add test with circular symbolic links
• revert f579c17

It should be also update tests.lib.path.Path.copytree method (e.g. git revert 99a4f6f) but it will add a dependency to pip.util module.

All comments are welcome

[alquerci]

rebase done

The commit history should be clean up after the review.

[dstufft]

Accidentally closed this, reopening. Sorry!

[BrownTruck]

Hello!

As part of an effort to ease the contribution process and adopt a more standard workflow pip has switched to doing development on the master branch. However, this Pull Request was made against the develop branch so it will need to be resubmitted against master. Unfortunately, this pull request does not cleanly merge against the current master branch.

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If this pull request is still valid, please rebase it against master (or merge master into it) and resubmit it against the master branch, closing and referencing the original Pull Request.

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Hello,

Reply to #1311

It's an answer of https://github.com/pypa/pip/pull/1311/files#r7640350

If a project contains true NTFS symlinks it require elevated privileges indeed (source: @docs.python: os.symlink and @wikipedia: NTFS_symbolic_link)



 Fix shutil.copytree for py3 when a symlink points to a directory

 Prevent circular symbolic links

 Add test with circular symbolic links

 revert pypa/pip@f579c17



It should be also update tests.lib.path.Path.copytree method (e.g. git revert pypa/pip@99a4f6f) but it will add a dependency to pip.util module.

All comments are welcome

---

*This was migrated from pypa/pip#1329 to reparent it to the ``master`` branch. Please see original pull request for any previous discussion.*

[alquerci]

Closing in favor of #3707