markup5ever aborts in build.rs

[emi2k01]

Repro:

git clone https://github.com/servo/html5ever --depth 1 && \
    cd html5ever/markup5ever && \
    cargo_cf build

It seems to crash in write_to(&mut generated) (grep it) when string cache string-cache calls AtomType::to_tokens in the body of write_to.

I don't know how to get the backtrace since it just aborts.

It works correctly with normal cargo.

[bjorn3]

Thanks for the issue. Markup5ever uses proc_macro2 in it's build script, which tries to detect if it s running inside a proc macro or not by invoking a function that panics when not run inside a proc macro. cg_clif doesn't support catching panics and thus aborts. This should have been fixed in dtolnay/proc-macro2#300, but it seems that I made a mistake with the #[cfg]. Opened dtolnay/proc-macro2#303 with a confirmed fix.

Duplicate of #1101

[bjorn3]

This should be fixed now as of proc-macro 1.0.33.