Under MinGW, x.py fails to run with UnboundLocalError.

[barik]

Under MinGW, x.py will fail with the following errors:

$ ./x.py
Traceback (most recent call last):
  File "./x.py", line 20, in <module>
    bootstrap.main()
  File "C:/src/rust/src/bootstrap/bootstrap.py", line 620, in main
    bootstrap()
  File "C:/src/rust/src/bootstrap/bootstrap.py", line 601, in bootstrap
    rb.build = rb.build_triple()
  File "C:/src/rust/src/bootstrap/bootstrap.py", line 459, in build_triple
    if os.environ.get('MSYSTEM') == 'MINGW64':
UnboundLocalError: local variable 'os' referenced before assignment

The reason is due to the build_triple function in src/bootstrap/bootstrap.py (Line 416):

if ostype == 'Linux':
    os = subprocess.check_output(['uname', '-o']).strip().decode(default_encoding)
        

Here, the assignment to os is causing the os module to be shadowed.

Then, in (Line 459):

if os.environ.get('MSYSTEM') == 'MINGW64':
    cputype = 'x86_64'

os now refers to the uninitialized local variable, not the os module.

Easiest fix is to simply rename the os variable to something like os_from_sp.

Also, there is a small typo fix in x.py referencing the wrong file name.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[alexcrichton]

@bors: r+

Thanks!

[bors]

📌 Commit 04e4d42 has been approved by alexcrichton

[bors]

⌛ Testing commit 04e4d42 with merge e4f1dc7...

[bors]

💔 Test failed - status-travis

[arielb1]

• Travis mac builder craziness (logs are empty)
  @bors retry