Do not run the default panic hook inside procedural macros.

[Zoxc]

Fixes#47812

r? @nikomatsakis

[nikomatsakis]

clearly we need to fix that test you mentioned -- or maybe we can do a UI test? Seems like we ought to be able to, no?

[Zoxc]

I don't know why the test does not work. It is already an UI test which tests stderr.

[nikomatsakis]

@Zoxc I'd like to understand that :/

[bors]

☔ The latest upstream changes (presumably #47203) made this pull request unmergeable. Please resolve the merge conflicts.

[Zoxc]

I probably should move the panic handler to librustc. I want to sneak in some printing of the query stack on panic too.

[nikomatsakis]

@Zoxc I did some investigating, not sure if I mentioned it here; I was not able to reproduce the problem except for on nightly builds. Any clue why that might be?

[nikomatsakis]

I guess we can land in the meantime, but it's vexing.

[Zoxc]

I don't have any ideas about why the test failed.

[Mark-Simulacrum]

This is the reason for the test failure: https://github.com/rust-lang/rust/blob/master/src/tools/compiletest/src/json.rs#L88. Specifically, non-JSON lines in the output are simply ignored by compiletest, which means that any UI test will fail to test this behavior.

I think the most straightforward fix here would be to change this to a run-make test.

@Zoxc Is there a chance you could make that change?

[Zoxc]

@Mark-Simulacrum So does compiletest ask for JSON output and then convert that into what the stderr output would be? Could we make it also emit the non-JSON lines to this output?

[Mark-Simulacrum]

Actually, now that I do some deeper investigation, it looks like if we put // compile-flags:--error-format human everything will work. We detect this in compiletest and if we see any format of error-format in the compile args we'll bail out of the JSON parsing and just check the raw outputs.

So looks like the fix is even simpler than I thought!

[nikomatsakis]

@Mark-Simulacrum thanks for that!

[nikomatsakis]

@bors r+

[bors]

📌 Commit 11b74ed has been approved by nikomatsakis

[bors]

🔒 Merge conflict

[nikomatsakis]

@Zoxc needs rebase :(

[Zoxc]

@bors r=nikomatsakis

[bors]

📌 Commit 9d3719b has been approved by nikomatsakis