rustbook fails to compile on Fedora 42 with all dependencies met

[Borgerr]

Summary

One dependency for building oniguruma related items are anything to do with libclang. This is currently insufficient for Fedora 42 x86 systems. C23, used by default in systems like fedora 42, currently breaks rustbook builds. (see more here) This ends up being problematic as a dependency of rustbook is mdbook-i18n-helpers, which does not compile well with this current setup.

Any previous version of mdbook-i18n-helpers, e.g. 3.6, 3.5, etc, does not compile, however, the latest activity on the head of their main branch does. Anything beyond this is speculative and should be discussed further below.

Command used

./x doc

Also mimicked by compiling strictly rustbook.

Expected behaviour

Documentation generation.

Actual behaviour

Unable to compile onigumura.

Bootstrap configuration (bootstrap.toml)

# See bootstrap.example.toml for documentation of available options
#
profile = "library"  # Includes one of the default files in src/bootstrap/defaults
change-id = 140732

Operating system

Fedora 42

HEAD

414482f

Build Log

My own build log is attached as a file ;)

build.log

[Borgerr]

My branch here doesn't pass tidy checks (so, shouldn't be taken seriously, unless git identifiers suddenly become accepted), but should work as a POC for this fix.

[jieyouxu]

AFAICT, this is not actionable for the bootstrap team. Either we'd have to:

• Get https://github.com/google/mdbook-i18n-helpers to release a new version with that somehow fixed, or
• rustbook somehow drops the dependency on mdbook-i18n-helpers.

cc @ehuss

[ehuss]

Looks like @cuviper has asked for a new release: google/mdbook-i18n-helpers#267 (comment).

[cuviper]

One dependency for building oniguruma related items are anything to do with libclang.

I don't know what clang has to do with this. The incompatible-pointer-types errors are new in GCC 15, having moved to C23 by default.

https://gcc.gnu.org/gcc-15/porting_to.html#c23-fn-decls-without-parameters

Oniguruma did fix this in 6.9.10, but onig_sys hasn't been updated in a long time (working on it here). But since the main repo is archived, I think it's better to wean ourselves anyway.

In the meantime, if you have oniguruma-devel installed, you can also get onig_sys to use that with env RUSTONIG_SYSTEM_LIBONIG=1.

(edit: I updated to the correct fix commit)

[ranger-ross]

I ran into this today.

Another work around that does not requiring installing oniguruma-devel is setting:

export CFLAGS='-std=gnu17'