libxslt not being able to find installed stylesheets

[jtojnar]

When running Meson tests on MacOS CI (this PR), gtk-doc failed to run because xsltproc (from libxslt) was not able to found docbook-xsl stylesheets, even though they were installed through brew install gtk-doc. libxml2-based tools like libxslt support XML catalogues as a mechanism for finding XSL stylesheets but, since Brew installs it to an unconventional location (/usr/local/etc/xml/catalog instead of the expected /etc/xml/catalog), they will not be able to see the installed files.

I know I can set XML_CATALOG_FILES but is that really the expected solution?

There was an issue about this but it got closed: Homebrew/homebrew-core#70769

[SMillerDev]

I know I can set XML_CATALOG_FILES but is that really the expected solution?

Yeah, that's the variable to control where to find catalogs

[jtojnar]

I know. But should not libxml2 installed by Homebrew be aware of Homebrew’s XML catalog out of the box?

[SMillerDev]

AFAIK libxml2 is rarely used from Homebrew since it's provided by macOS. It might be an oversight or maybe there is just no way to edit this location at compile time. I don't know.

[carlocab]

I know. But should not libxml2 installed by Homebrew be aware of Homebrew’s XML catalog out of the box?

PRs to improve this behaviour welcome.

[jtojnar]

It might be an oversight or maybe there is just no way to edit this location at compile time. I don't know.

You can pass -DXML_XML_DEFAULT_CATALOG to the compiler to change the default path:

https://gitlab.gnome.org/GNOME/libxml2/-/blob/95766541622b3a66c929e2e272b0252750d0174d/catalog.c#L71

PRs to improve this behaviour welcome.

Sorry, Homebrew is three degrees of separation from the project I was trying to fix (I do not personally even use MacOS) so I won’t be able to do that.