Installing 1.15.0 from source fails in bootstrap.py

[djc]

While updating the Gentoo package for rust to 1.15.0, I get this error:

Traceback (most recent call last):
  File "/var/tmp/portage/dev-lang/rust-1.15.0/work/rustc-1.15.0-src/src/bootstrap/bootstrap.py", line 491, in <module>
    main()
  File "/var/tmp/portage/dev-lang/rust-1.15.0/work/rustc-1.15.0-src/src/bootstrap/bootstrap.py", line 440, in main
    if os.environ['USER'] != os.environ['SUDO_USER']:
  File "/usr/lib64/python2.7/UserDict.py", line 40, in __getitem__
    raise KeyError(key)
KeyError: 'USER'

This appears to have been introduced as part of 0e272de, the commit that switched to rustbuild by default. I don't really get what the USER != SUDO_USER heuristic is intended to protect against, but it looks a bit fishy to me. For one thing, from this failure it would seem that it has not seen testing in very diverse environments, so using .get('USER') and .get('SUDO_USER') would probably make a lot more sense here. Second, while the goal appears to be to set enable_vendored_sources in some situations, this code is still executed when enable_vendored_sources is already set. Finally, there is a typo in the help text that is printed for this case ('intall').

[durka]

Strange, Gentoo doesn't have $USER or names it something else?

[alexcrichton]

This was originally intended to detect sudo make install and warn you that you should do make first then sudo make install. There's no need for us to require these env vars, though, so a patch to use .get should work just fie!

[djc]

@durka I think it has it, but it's probably not available in the constrained environment set up by the package manager.

[djc]

Would it make sense to uplift this to 1.16.0? If so, how do I go about nominating it?

[alexcrichton]

@djc sure yeah, I've nominated #39471 for a backport (tag)