output colors broken on beta and nightly

[durka]

stable:

beta:

nightly:

[nrc]

There have been more than a few changes to diagnostics in rustc, but the colouring on the terminal is still OK. Looking through the playpen source I don't see anywhere obvious this could be going wrong.

[durka]

I was going to try to inspect the color codes that rustc produces, but I can't convince it to show them to me at all:

TERM=xterm rustc foo.rs --color=always 2>&1 | xxd

this produces no color codes in the output, on any release channel. Confusing.

[nrc]

I wonder if that broke as part of the diagnostics work. Would that cause this breakage? Looks like it might from the source code, but I don't really understand it.

Ah, but I would expect this to work on the release channel, if that were the case.

[durka]

If you look in the network console, it's simply not sending any color codes in the compiler output for beta and nightly. Did something change in how it process $TERM? I seem to remember that libterm was updated.

[durka]

Sorry, it does produce colors on stable, I was wrong before. So something changed such that after 1.6.0 rustc checks for a terminal and can't be convinced to print colors to a non-terminal. This seems like a bug, anyway, since --color=always exists.

[TimNN]

I'm pretty sure that rust-lang/rust#29999 inadvertently brought this to light since it somehow changed how term::stderr() works: colours will only be used when destination is a Terminal, which is only the case if term::stderr() returns Some(_) (see emitter.rs:686).

[respeccing]

Looks like this got fixed and is no longer and issue.

https://play.rust-lang.org/?gist=2f5920fe579ff82b69b87b94b8727d7f&version=stable&backtrace=0

[alexcrichton]

Indeed! (I believe this was fixed)