Fix flaky test

[jyn514]

Rustdoc writes to a pipe, and if the program on the other side has
exited, it will exit with SIGPIPE. To avoid that happening, call rustc
instead of true, which will wait to exit until it sees EOF on stdin.

cc #79705 (comment), #80924 (comment)

r? @ijackson

[rust-log-analyzer]

The job x86_64-gnu-llvm-9 failed! Check out the build log: (web)(plain)

Click to see the possible cause of the failure (guessed by this bot)

Suite("src/test/assembly") not skipped for "bootstrap::test::Assembly" -- not in ["src/tools/tidy"]
Check compiletest suite=assembly mode=assembly (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
running 29 tests
iiiiiiiiiiiiiiiiiiiiiiiiiiiii
finished in 0.059 seconds
Suite("src/test/incremental") not skipped for "bootstrap::test::Incremental" -- not in ["src/tools/tidy"]
Check compiletest suite=incremental mode=incremental (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
---
Suite("src/test/debuginfo") not skipped for "bootstrap::test::Debuginfo" -- not in ["src/tools/tidy"]
Check compiletest suite=debuginfo mode=debuginfo (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
running 116 tests
iiiiiiiiii.i.i..i..i..ii....i.i....ii..........iiii..........i....i...i.......ii.i.ii.....iiii.....i 100/116
test result: ok. 78 passed; 0 failed; 38 ignored; 0 measured; 0 filtered out; finished in 1.86s
finished in 1.922 seconds
Suite("src/test/ui-fulldeps") not skipped for "bootstrap::test::UiFullDeps" -- not in ["src/tools/tidy"]
---
---- [rustdoc] rustdoc/issue-80893.rs stdout ----
error: rustdoc failed!
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustdoc" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/issue-80893/auxiliary" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/issue-80893" "/checkout/src/test/rustdoc/issue-80893.rs" "--test" "-Z" "unstable-options" "--test-builder" "rustc"
------------------------------------------
running 1 test
test /checkout/src/test/rustdoc/issue-80893.rs - Foo (line 3) ... FAILED
test /checkout/src/test/rustdoc/issue-80893.rs - Foo (line 3) ... FAILED
failures:
---- /checkout/src/test/rustdoc/issue-80893.rs - Foo (line 3) stdout ----
thread '/checkout/src/test/rustdoc/issue-80893.rs - Foo (line 3)' panicked at 'Failed to spawn rustc process: Os { code: 2, kind: NotFound, message: "No such file or directory" }', src/librustdoc/doctest.rs:317:38
failures:
---
test result: FAILED. 410 passed; 1 failed; 2 ignored; 0 measured; 0 filtered out; finished in 25.59s
command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--rustdoc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustdoc" "--src-base" "/checkout/src/test/rustdoc" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--suite" "rustdoc" "--mode" "rustdoc" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-9/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python3" "--lldb-python" "/usr/bin/python3" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "9.0.0" "--llvm-components" "aarch64 aarch64asmparser aarch64codegen aarch64desc aarch64disassembler aarch64info aarch64utils aggressiveinstcombine all all-targets amdgpu amdgpuasmparser amdgpucodegen amdgpudesc amdgpudisassembler amdgpuinfo amdgpuutils analysis arm armasmparser armcodegen armdesc armdisassembler arminfo armutils asmparser asmprinter avr avrasmparser avrcodegen avrdesc avrdisassembler avrinfo binaryformat bitreader bitstreamreader bitwriter bpf bpfasmparser bpfcodegen bpfdesc bpfdisassembler bpfinfo codegen core coroutines coverage debuginfocodeview debuginfodwarf debuginfogsym debuginfomsf debuginfopdb demangle dlltooldriver engine executionengine fuzzmutate globalisel hexagon hexagonasmparser hexagoncodegen hexagondesc hexagondisassembler hexagoninfo instcombine instrumentation interpreter ipo irreader jitlink lanai lanaiasmparser lanaicodegen lanaidesc lanaidisassembler lanaiinfo libdriver lineeditor linker lto mc mca mcdisassembler mcjit mcparser mips mipsasmparser mipscodegen mipsdesc mipsdisassembler mipsinfo mirparser msp430 msp430asmparser msp430codegen msp430desc msp430disassembler msp430info native nativecodegen nvptx nvptxcodegen nvptxdesc nvptxinfo objcarcopts object objectyaml option orcjit passes perfjitevents powerpc powerpcasmparser powerpccodegen powerpcdesc powerpcdisassembler powerpcinfo profiledata remarks riscv riscvasmparser riscvcodegen riscvdesc riscvdisassembler riscvinfo riscvutils runtimedyld scalaropts selectiondag sparc sparcasmparser sparccodegen sparcdesc sparcdisassembler sparcinfo support symbolize systemz systemzasmparser systemzcodegen systemzdesc systemzdisassembler systemzinfo tablegen target textapi transformutils vectorize webassembly webassemblyasmparser webassemblycodegen webassemblydesc webassemblydisassembler webassemblyinfo windowsmanifest x86 x86asmparser x86codegen x86desc x86disassembler x86info x86utils xcore xcorecodegen xcoredesc xcoredisassembler xcoreinfo xray" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
failed to run: /checkout/obj/build/bootstrap/debug/bootstrap --stage 2 test --exclude src/tools/tidy
Build completed unsuccessfully in 0:14:27

[jyn514]

Oh boo, rustc isn't available on CI because the only compiler available is the one built from source, which isn't in PATH.

Maybe we should just remove this test?

[Mark-Simulacrum]

A run-make test should be able to do provide the rustc path correctly.

[jyn514]

Thanks, done. I had to build rustdoc for run-make tests.

r? @Mark-Simulacrum

[jyn514]

@bors p=5

This is causing spurious failures.

[jyn514]

@bors p=0

#81231 is fixing the immediate issue.

[Mark-Simulacrum]

r=me with two nits fixed

[Mark-Simulacrum]

I would prefer to avoid this and instead move the test to fulldeps.

[jyn514]

That seems a shame when this doesn't actually need a stage 2 build :/ that means you have to compiler rustc twice to run the test at all. Rustdoc only takes about a minute to build even with a clean cache.

[Mark-Simulacrum]

I don't want to make this change in this PR. We can consider it separately.

[jyn514]

Ok, I reverted the change. I do think it would be useful though - #81223 could also use it, and that test is much more likely to fail, so building the compiler twice is painful.

[Mark-Simulacrum]

r=me with commits squashed

[jyn514]

@bors r=Mark-Simulacrum rollup

[ijackson]

Wouldn't e.g. cat also have the same effect of exiting at EOF rather than immediately? If so, we could use a regular UI test.

AIUI the program we specify here gets passed rustc flags. So we need something that:

• will accept or ignore rustc command line options
• will read the whole input
• works on Windows too (which I think rules out something like providing a little script which is a wrapper around cat >/dev/null)

rustc seems like the obvious answer. Maybe we are getting the stage0 rustc and we need a stage1?

[Mark-Simulacrum]

Yeah I'm afraid I don't have the time to do a deep dive into why the rustc being passed isn't found; I would recommend starting by making sure it is getting passed by printing out the command rustdoc tries to run when it fails...

[JohnCSimon]

@jyn514 - looks like this already has an approval and is waiting for merge.
@rustbot label: +S-waiting-on-review -S-waiting-on-author

[jyn514]

@JohnCSimon This fails when tested on windows: #81197 (comment)

@rustbot label: +S-waiting-on-author -S-waiting-on-review

[jyn514]

Yeah I'm afraid I don't have the time to do a deep dive into why the rustc being passed isn't found; I would recommend starting by making sure it is getting passed by printing out the command rustdoc tries to run when it fails...

I've tried to do this for about 15 minutes now and I'm really stumped - is there a way to show the output when a run-make test passes?

Here's what I've tried so far:

Details

diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 86d940cd733..9a33d952ff1 100644
--- a/src/bootstrap/test.rs+++ b/src/bootstrap/test.rs@@ -1257,7 +1257,7 @@ fn run(self, builder: &Builder<'_>) {
cmd.arg("--verbose");
}
- if !builder.config.verbose_tests {+ if !builder.config.verbose_tests && !builder.is_verbose() {
cmd.arg("--quiet");
}
@@ -1808,7 +1808,7 @@ fn run(self, builder: &Builder<'_>) {
cargo.arg("--");
cargo.args(&builder.config.cmd.test_args());
- if !builder.config.verbose_tests {+ if !builder.config.verbose_tests && !builder.is_verbose() {
cargo.arg("--quiet");
}
@@ -1921,7 +1921,7 @@ fn run(self, builder: &Builder<'_>) {
dylib_path.insert(0, PathBuf::from(&*builder.sysroot_libdir(compiler, target)));
cargo.env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
- if !builder.config.verbose_tests {+ if !builder.config.verbose_tests && !builder.is_verbose() {
cargo.arg("--quiet");
}
@@ -1992,7 +1992,7 @@ fn run(self, builder: &Builder<'_>) {
cargo.arg("'-Ctarget-feature=-crt-static'");
}
- if !builder.config.verbose_tests {+ if !builder.config.verbose_tests && !builder.is_verbose() {
cargo.arg("--quiet");
}

$ RUST_TEST_NOCAPTURE=1 xpy test src/test/run-make-fulldeps --test-args rustdoc-test-builder -v
running 1 test
test [run-make] run-make-fulldeps/rustdoc-test-builder ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 221 filtered out; finished in 0.04s
finished in 0.086 seconds

[jyn514]

Also, if there's a way to get CI to run tests for Windows instead of Linux on PR builds, that would be super helpful.

[crlf0710]

Also, if there's a way to get CI to run tests for Windows instead of Linux on PR builds, that would be super helpful.

I think it's possible. Maybe just edit the CI related configurations temporarily in this PR... and revert the changes after it's ready.

[jyn514]

I'm not planning to spend any more time on this.