x.py clean does not clean bootstrap anymore

[matthiaskrgr]

./x.py clean used to clean the compiled artifacts of the bootstrap tool, this no longer seems to be the case.
After running x.py clean, build/bootstrap was not removed.

I also noticed that on a clean build, ./x.py check would build bootstrap twice; first it would be compiler at the beginning, then it would be checked at the very end of the compilation again, is this intended?

Updating only changed submodules
Submodules updated in 0.03 seconds
   Compiling proc-macro2 v1.0.19
   Compiling unicode-xid v0.2.1
   Compiling memchr v2.3.3
   Compiling syn v1.0.38
   Compiling serde_derive v1.0.115
   Compiling libc v0.2.74
   Compiling lazy_static v1.4.0
   Compiling cfg-if v0.1.10
   Compiling log v0.4.11
   Compiling serde v1.0.115
   Compiling autocfg v1.0.0
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   Compiling same-file v1.0.6
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   Compiling unicode-width v0.1.8
   Compiling cc v1.0.58
   Compiling itoa v0.4.6
   Compiling build_helper v0.1.0 (/home/matthias/vcs/github/rust/src/build_helper)
   Compiling opener v0.4.1
   Compiling thread_local v1.0.1
   Compiling crossbeam-utils v0.7.2
   Compiling walkdir v2.3.1
   Compiling getopts v0.2.21
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   Compiling bootstrap v0.0.0 (/home/matthias/vcs/github/rust/src/bootstrap)
    Finished dev [unoptimized + debuginfo] target(s) in 44.28s
Checking std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[...]
    Checking clippy_lints v0.0.212 (/home/matthias/vcs/github/rust/src/tools/clippy/clippy_lints)
    Finished release [optimized] target(s) in 19.51s
Checking bootstrap artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
   Compiling syn v1.0.38
    Checking fnv v1.0.7
    Checking same-file v1.0.6
    Checking cc v1.0.58
    Checking opener v0.4.1
    Checking build_helper v0.1.0 (/home/matthias/vcs/github/rust/src/build_helper)
    Checking ansi_term v0.11.0
    Checking difference v2.0.0
    Checking walkdir v2.3.1
    Checking cmake v0.1.44
    Checking pretty_assertions v0.6.1
    Checking bstr v0.2.13
    Checking time v0.1.43
    Checking globset v0.4.5
    Checking ignore v0.4.16
   Compiling serde_derive v1.0.115
    Checking serde v1.0.115
    Checking serde_json v1.0.57
    Checking toml v0.5.6
    Checking bootstrap v0.0.0 (/home/matthias/vcs/github/rust/src/bootstrap)
    Finished release [optimized] target(s) in 15.75s
Build completed successfully in 0:04:41

Seems to be related to #76423 , cc @Mark-Simulacrum

[Mark-Simulacrum]

The double check changed in #76258, intentionally, because I wanted to check bootstrap's cfg(test) annotated bits too. Maybe it should be off by default though; ideally we'd have some sort of "this branch changed bootstrap" to auto-enable that but.. that's hard.

I am unsure why x.py clean stopped removing bootstrap, since the snippet of code seems to still be there:

rust/src/bootstrap/bootstrap.py

Lines 710 to 711 in 3f5e617

	if self.clean and os.path.exists(build_dir):
	shutil.rmtree(build_dir)

. Bisecting that would be helpful.

[RalfJung]

I don't think it ever cleaned bootstrap? I thought that was a feature.^^

[Mark-Simulacrum]

I don't think it was intentional to not do so, indeed looking at the git blame it seems like we explicitly did want to delete the build system: ac19420