catkin_make and friends fail to correctly resolve paths when invoked inside symlinked folders

[tkruse]

To reproduce

# in basefolder, e.g. /tmp
mkdir origin
mkdir hydro-ws
cd hydro-ws/
ln -s ../origin/ src
cd src
catkin_make -C ..

Result:
The specified source space "/src" does not exist

Should be:
Building in basefolder/hydro-ws

The issue was originally discovered by @dirk-thomas in #603 and used as a reason to reject new features. Not sure why it was not ticketed and/or fixed since then, maybe keeping this bug can help reject more undesired pull requests in the future.
A function used to fix the buggy behavior was also originally given in PR #603, and would be merged in catkin by now if the maintainers had cared.

[dirk-thomas]

Thank you for filling the ticket.

The problem is that Python is not aware that it is invoked in /tmp/hydro-ws/src as far as I can see. If you run the following command in that folder:

python -c "import os; print(os.getcwd())"

it outputs /tmp/origin as the already resolved symlinked location. I am not aware of any method how Python could get the information that it was actually in /tmp/hydro-ws/src. But I think this piece of information would be necessary to resolve the scenario you describe.

If you do know a way how Python can get the required information please share it and I will be happy to resolve the the described bug in the catkin_make and catkin_make_isolated tools.

[tkruse]

As I have said before, I had already solved this in #603 using

python -c "import os; print(os.getenv('PWD'))"

https://github.com/tkruse/catkin/commit/de98d064b32eea82b023a2056f25dba4a70edb3a

In catkin/python/catkin/workspace.py

def get_cwd_rel_path(rel_or_abspath):
    '''returns the path if absolute, cwd if None, else cwd joined with the given relative path'''
    if rel_or_abspath and os.path.isabs(rel_or_abspath):
        return rel_or_abspath
    # Many, but not all shells, support this var that contains the path preserving symbolic link structures
    pwdpath = os.getenv('PWD')
    if pwdpath is None:
        # this function normalizes the path, does not follow symbolic links
        pwdpath = os.getcwd()
    if rel_or_abspath is not None:
        pwdpath = os.path.join(pwdpath, rel_or_abspath)
    return pwdpath

This then has to be invoked in the repsective places in catkin_make and catkin_make_isolated, as I had done in my pull request, until you kept on dismissing my PR due to this catkin bug.

[dirk-thomas]

Since you removed the code from your pull request at some time that information was not publically available anymore.

With that snippet I was able to create a pull request which should address this bug. Please try #639 and verify that it works for you, too.