rustbuild: There are two tmp/ directories

[alexcrichton]

When doing a build with rustbuild, it turns out that two tmp/ dirs end up being created. One is in the build/ directory that rustbuild owns, and one is in the current directory (next to the build directory). The one next to the build directory contains some information for partitioning tests and information about the error index. Both of these shouldn't exist and their output should be in the rustbuild build/ directory.

[cyplo]

More on rustbuild: https://internals.rust-lang.org/t/the-rustbuild-feature-thread/3643/

[Mark-Simulacrum]

I seem to recall seeing a tmp directory inside build, but I can't seem to recreate it now. Maybe it only appears temporarily during some particular steps and I've deleted it.

@alexcrichton What do you see as the steps for removing the tmp directory inside build/? Or is the solution to leave that and move the tmp directory created in the root into the build/ directory?

[alexcrichton]

I'd advocate to move the root tmp directory into the build/ directory, personally. The strategy here is to track down what's creating that dir (I'm not sure myself) and just update it to all use the build/ dir

[mati865]

Doesn't seem to be case anymore, ./x.py build creates only build/tmp/.

[petrochenkov]

Perhaps x.py test creates it because I still see the second tmp outside of the build directory created in the last few days.

[mati865]

@rustbot claim

Indeed x.py test created this directory, I'll see if I can fix it.

[mati865]

This directory is created by codegen-units tests which use // compile-flags: -Zincremental=tmp/partitioning-tests/* like here.

I'll have PR soon.

[petrochenkov]

cc #63429 (re-adds the outer tmp to .gitignore).