Fix path comparison between tools/bazel and bazelisk source

[clintharrison]

The os.path.join() here was resulting in ~/foo/./tools/bazel being compared to ~/foo/tools/bazel, which should actually match, but didn't.

[philwo]

Thank you!

[philwo]

@clintharrison Alternatively, what about using os.path.samefile here?

Return True if both pathname arguments refer to the same file or directory. This is determined by the device number and i-node number and raises an exception if an os.stat() call on either pathname fails.

[clintharrison]

@clintharrison Alternatively, what about using os.path.samefile here?

Return True if both pathname arguments refer to the same file or directory. This is determined by the device number and i-node number and raises an exception if an os.stat() call on either pathname fails.

Cool! I like that more -- I didn't realize py3 supported that on Windows now. It's not Windows-compatible in py2, but it looks like we don't intend on having py2 compatibility anymore?

[philwo]

Mhm, I would like to preserve Python 2.7 compatibility until the end of this year. What about this:

try:
  if not os.path.samefile(wrapper, __file__):
    return wrapper
except AttributeError:
  # Python 2.x on Windows does not support os.path.samefile yet.
  if os.path.abspath(wrapper) != os.path.abspath(__file__):
    return wrapper

We can then remove the try/catch when we finally drop Python 2.x support together with everyone else in the world beginning of 2020 😊

[clintharrison]

Ok, that's fair! That looks like a good alternative to me.

(Though I do wonder if anyone runs it with py2 in practice? It has a py3 shebang.)

[philwo]

Ok, that's fair! That looks like a good alternative to me.

(Though I do wonder if anyone runs it with py2 in practice? It has a py3 shebang.)

You have a point there :D I just checked the issue history and found that I actually promised users in #6 (comment) that it's compatible with Python 2 and 3. I don't remember why I didn't change the shebang to just /usr/bin/python at the time. 🤔

However, luckily this will all be much simpler in 2 months, when we can move to Python 3 only.