1289988 - Do something when terminal is mintty

Status: NEW

(Firefox Build System :: General, defect)

Description

[Mike Hommey [:glandium]]

It turns out that running mach (or any python for that matter) under mintty (which happens to be the default terminal emulator with msys2), makes sys.stdin/stdout/stderr be *non* ttys, which has multiple consequences:
- stdout is not line-buffered, which means in many cases, nothing is printed out
- things like the raw_input() function seem to want to open a tty, and consequently don't work in mintty. Combined with the above, for example, this leaves mach boostrap hanging printing nothing and not responding to input where it would normally print a message and expect the user to enter a number.
- mach itself relies on whether stdout is a tty to trigger auto-logging.
- while it doesn't work currently because of the lack of a curses package, mach output colorization relies on the same property.
- etc.

Even the python CLI doesn't work for the same reasons.

Fortunately, under normal conditions, we can detect the terminal emulator is mintty: in that case, the MSYSCON environment variable is set to mintty.exe. We can also distinguish between the process output being redirected to a file or being set to the terminal (S_ISREG vs. S_ISFIFO). But it's not straightforward to distinguish between terminal and pipe, since the terminal is actually using a pipe :(.

All that to say: We need to do something because things won't work properly under mintty, but the remaining question is: what?

Comment 1

[Mike Hommey [:glandium]]

Related:
http://stackoverflow.com/questions/13588454/invoking-python-under-cygwin-on-windows-hangs
https://github.com/mintty/mintty/issues/56

Comment 2

[Gregory Szorc [:gps]]

This likely also explains why Mercurial doesn't behave well in mintty.

Comment 3

[Ryan VanderMeulen [:RyanVM]]

Isn't that what winpty is supposed to help with?

Comment 4

[Mike Hommey [:glandium]]

(In reply to Ryan VanderMeulen [:RyanVM] from comment #3)
> Isn't that what winpty is supposed to help with?

Yes, but aiui, you need to wrap all your commands with it.

Comment 5

[Mike Hommey [:glandium]]

We /could/ reexecute mach under it, but that would break `mach command | foo`