Print a summary of which test suite failed

[Mark-Simulacrum]

Especially on CI, where cross-compiling is common and single builder may end up
with multiple hosts and multiple targets, it can be annoying to scroll back to
the nearest start of test marker. This prints out a summary of the test suite
being run directly in compiletest.

For example, on a mir-opt failure, this would show something like this:

failures:
    [mir-opt] mir-opt/while-storage.rs

test result: FAILED. 140 passed; 1 failed; 2 ignored; 0 measured; 0 filtered out

Some tests failed in compiletest suite=mir-opt mode=mir-opt host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu

Fixes #78517

[rust-highfive]

@Mark-Simulacrum: no appropriate reviewer found, use r? to override

[Mark-Simulacrum]

r? @jyn514 perhaps?

cc @RalfJung

[RalfJung]

Looks great!
I guess what I am most surprised by is how far away this is from the code that prints the "header" above the tests:

rust/src/bootstrap/test.rs

Line 1299 in a6403b0

"Check compiletest suite={} mode={} ({} -> {})",

Do you want to keep these two in sync in terms of output? One uses HOST -> TARGET, the other host=HOST, target=TARGET.

[Mark-Simulacrum]

IMO the HOST -> TARGET terminology is a bit confusing and likely not immediately obvious; I don't personally care to change the (many) locations in bootstrap right now, but I also think consistency in this case is not too important.

I think this could be in bootstrap but -- as you noted on the issue -- it'd be annoying to pipe the relevant data in, and here we immediately have it available.

[jyn514]

Some tests failed in compiletest suite=mir-opt mode=mir-opt

Will the suite and mode ever be different? r=me if so, but otherwise I don't think we need to print both.

[Mark-Simulacrum]

I don't have the time to do a detailed investigation, but I suspect the answer is yes (or, at least, that this is plausible). The two are tracked and passed as separate things in bootstrap as well.

[jyn514]

Ok, they can be different:

host_test!(UiFullDeps { path: "src/test/ui-fulldeps", mode: "ui", suite: "ui-fulldeps" });
--
    mode: "run-make",
    suite: "run-make-fulldeps"
--
                mode: "js-doc-test",
                suite: "rustdoc-js",
--
            mode: "ui",
            suite: "rustdoc-ui",
--

@bors r+

[bors]

📌 Commit f289a87 has been approved by jyn514

[bors]

💡 This pull request was already approved, no need to approve it again.

• There's another pull request that is currently being tested, blocking this pull request: Codegen: Query span as late as possible #78280

[bors]

📌 Commit f289a87 has been approved by jyn514