tests/ui/io-checks fail locally on master

[WaffleLapkin]

The tests/ui/io-checks/inaccessbile-temp-dir.rs test fails for me locally on the master branch (and was failing for a while now). I can of course ignore it, but it's annoying. tests/ui/io-checks/non-ice-error-on-worker-io-fail.rs also fails if run after/with inaccessbile-temp-dir.rs.

It looks like inaccessbile-temp-dir.rs successfully creates a temp directory even if it's parent does not exist:

output

:~/rust-b (master); git log -1 --oneline
91b61a4ad61 (HEAD -> master, upstream/master) Auto merge of #110389 - mazong1123:add-shortcut-for-grisu3, r=Mark-Simulacrum
:~/rust-b (master); ls /does-not-exist
ls: cannot access '/does-not-exist': No such file or directory
:~/rust-b (master) [2]; x t tests/ui/io-checks/inaccessbile-temp-dir.rs
Building bootstrap
    Finished dev [unoptimized] target(s) in 0.06s
Building stage0 library artifacts (aarch64-unknown-linux-gnu)
    Finished release [optimized + debuginfo] target(s) in 0.18s
Building compiler artifacts (stage0 -> stage1, aarch64-unknown-linux-gnu)
    Finished release [optimized + debuginfo] target(s) in 0.29s
Assembling stage1 compiler
Building stage1 library artifacts (aarch64-unknown-linux-gnu)
    Blocking waiting for file lock on package cache
    Blocking waiting for file lock on package cache
    Finished release [optimized + debuginfo] target(s) in 0.21s
Building stage0 tool compiletest (aarch64-unknown-linux-gnu)
    Finished release [optimized + debuginfo] target(s) in 0.19s
Check compiletest suite=ui mode=ui (aarch64-unknown-linux-gnu -> aarch64-unknown-linux-gnu)

running 1 tests
F

failures:

---- [ui] tests/ui/io-checks/inaccessbile-temp-dir.rs stdout ----

error: ui test compiled successfully!
status: exit status: 0
command: "/home/gh-WaffleLapkin/rust-b/build/aarch64-unknown-linux-gnu/stage1/bin/rustc" "/home/gh-WaffleLapkin/rust-b/tests/ui/io-checks/inaccessbile-temp-dir.rs" "-Zthreads=1" "--sysroot" "/home/gh-WaffleLapkin/rust-b/build/aarch64-unknown-linux-gnu/stage1" "--target=aarch64-unknown-linux-gnu" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Zdeduplicate-diagnostics=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/home/gh-WaffleLapkin/rust-b/build/aarch64-unknown-linux-gnu/test/ui/io-checks/inaccessbile-temp-dir" "-A" "unused" "-Crpath" "-Cdebuginfo=0" "-Lnative=/home/gh-WaffleLapkin/rust-b/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/home/gh-WaffleLapkin/rust-b/build/aarch64-unknown-linux-gnu/test/ui/io-checks/inaccessbile-temp-dir/auxiliary" "-Z" "temps-dir=/does-not-exist/output"
stdout: none
stderr: none



failures:
    [ui] tests/ui/io-checks/inaccessbile-temp-dir.rs

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 14869 filtered out; finished in 60.70ms

Some tests failed in compiletest suite=ui mode=ui host=aarch64-unknown-linux-gnu target=aarch64-unknown-linux-gnu
Build completed unsuccessfully in 0:00:03
:~/rust-b (master) [1]; ls /does-not-exist
output
:~/rust-b (master); 

This causes the failure (as the test is expected to not compile) and also creates the directory, which non-ice-error-on-worker-io-fail.rs then observes and also fails.

This happens for me on the dev-desktop-eu-1.

cc @fee1-dead iirc you had the same problems
cc @cuviper you changed those tests at some point, so maybe you know something

[KittyBorgX]

Summing up findings from discord, This test is wrong in its entirity since it gambles on permissions. The underlying rustc subcommand creates the dir if you have enough permission to create in / so it would fail. Otherwise, the directory is never created due to insufficient user permission, so the test passes.

To sum it up, the test passed (for me) since I did not have enough permission to create a new directory (/does-not-exist/output) in /:

[WaffleLapkin]

The test assumes that the compiler uses create_dir and so it must fail to create /does-not-exist/another-dir, but this is actually not the case:

rust/compiler/rustc_interface/src/passes.rs

Lines 608 to 612 in 999e6e5

	if let Some(ref dir) = sess.io.temps_dir {
	if fs::create_dir_all(dir).is_err() {
	sess.emit_fatal(errors::TempsDirError);
	}
	}

The test happens to pass in the CI and for many developers because you generally can't create a directory in /. However this is not always the case (for example I happen to run tests in chroot).

@jyn514 suggests that the proper fix for the test would be for the test to create an inaccessible directory, basically making a run-make analog to chmod 000 some-dir && rustc -Z temps-dir=some-dir/foo

[cuviper]

the proper fix for the test would be for the test to create an inaccessible directory, basically making a run-make analog to chmod 000 some-dir && rustc -Z temps-dir=some-dir/foo

That still doesn't work if you're the root user, but I guess that's not what you're doing in your chroot?

You could use a path like /proc/... where even root can't create anything, but there's no OS-agnostic path like that.

[WaffleLapkin]

That still doesn't work if you're the root user, but I guess that's not what you're doing in your chroot?

I guess my point is that inaccessbile-temp-dir.rs was broken on root anyway (because root has access to /, same as in chroot). The explanation in the test was because of the original non-ice-error-on-worker-io-fail.rs test it looks like, which works because it uses -o which requires at least the "parent must exist".

So change /dev/null -> /does-not-exist/output

• non-ice-error-on-worker-io-fail.rs now works on root, but doesn't work on chroot anymore
• inaccessbile-temp-dir.rs does not work on root/chroot, but also doesn't clobber /dev/null

My change:

• non-ice-error-on-worker-io-fail.rs unchanged
• inaccessbile-temp-dir.rs now works in chroot

Sooo, while inaccessbile-temp-dir.rs fails on root, since it doesn't have global effects (clobbering /dev/null as it originally did), I don't think it's a big deal. IMO you are not supposed to run tests on root (but it's also bad for tests to have global effects)...

[cuviper]

Yeah, that's fair -- we don't have to support root, but it should at least do no harm.

While you're poking at that, maybe you can fix the filename spelling to "inaccessible"?

[WaffleLapkin]

Fixed the spelling, thanks.