gobject-introspection and not finding cairo

Hello,

I'm trying to build some new packages, one of which is ghc-gi-cairo (from ghc-haskell-gi: https://github.com/haskell-gi/haskell-gi).These depend on gobject-introspection and finding library information from gir. However, it appears the typelib for cairo does not include the absolute path for cairo (though gobject-introspection right now does not depend on cairo, so that makes sense?) and the library cannot be found from this info.

Perhaps the name exposed in the typelib should be something else? I know there are patches for paths in gobject-introspection, and this issue of library path from gobject-introspection is not just in guix (e.g. https://github.com/Cimbali/pympress/issues/58).In building I do see LIBRARY_PATH includes the correct gobject-introspection (it does find the girepository in configure) and cairo, but as far as I can tell the path to cairo must be found via the typelib when using gobject-introspection?

I've tried building gobject-introspection with cairo enabled in meson, which didn't help. I also tried patching the cairo.gir file (as in https://github.com/Cimbali/pympress/issues/58#issuecomment-503174954),but haven't figured out what needs to go in there to make it work. Probably gobject-introspection needs to be build with cairo as an input and correctly get the full path to the library in generating the typelib? But what goes in the gir/cairo-1.0.gir.in file exactly?

From the gobject-introspection package running:

strings /gnu/store/irmw6agiw3adqphw8c3m19g31fw1yf34-gobject-introspection-1.62.0/lib/girepository-1.0/cairo-1.0.typelib | grep lib

has output:

libcairo-gobject.so.2

xlib

End of building ghc-gi-cairo has the following message:

starting phase `configure'

running "runhaskell Setup.hs" with command "configure" and parameters ("--prefix=/gnu/store/w95yciqs7i7aqm6v7qa6fiy6m6f25czb-ghc-gi-cairo-1.0.25" "--libdir=/gnu/store/w95yciqs7i7aqm6v7qa6fiy6m6f25czb-ghc-gi-cairo-1.0.25/lib" "--docdir=/gnu/store/w95yciqs7i7aqm6v7qa6fiy6m6f25czb-ghc-gi-cairo-1.0.25/share/doc/ghc-gi-cairo-1.0.25" "--libsubdir=$compiler/$pkg-$version" "--package-db=/tmp/guix-build-ghc-gi-cairo-1.0.25.drv-0/package.conf.d" "--global" "--enable-tests" "--enable-shared" "--enable-executable-dynamic" "--ghc-option=-fPIC" "--ghc-option=-optl=-Wl,-rpath=/gnu/store/w95yciqs7i7aqm6v7qa6fiy6m6f25czb-ghc-gi-cairo-1.0.25/lib/$compiler/$pkg-$version")

** (process:19): WARNING **: 17:28:36.142: Failed to load shared library 'libcairo-gobject.so.2' referenced by the typelib: libcairo-gobject.so.2: cannot open shared object file: No such file or directory

Could not resolve symbol "cairo_gobject_context_get_type" in namespace "cairo-1.0"

Appreciate any tips, help, or things to try!

John

I've managed to fix the initial problem I noted, but this would depend on having cairo as an input so that gobject-introspection can find the library to patch the typelib. Unfortunately, this would be a circular dependency. This is a long standing issue with how cairo is handled here (see, e.g., https://gitlab.freedesktop.org/cairo/cairo/-/issues/141).

I don't know how circular dependencies are solved in guix, so I'm not sure what to do to fix this. gobject-introspection doesn't need cairo to build or function, so the build depends is not really needed other than to fix this bug. So this could be done with a separate package or in two steps?

Of course, saw right after my last message that the dependency cycle here is through poppler, and cairo-sans-poppler exists. So I think I've solved this problem and will submit a patch.

I've attached the current changes I've been working on and testing for now.

Hi John!

You could try creating a gobject-introspection variant with cairo

enabled and use that variant as native-input for your packages.

Something like this:

```

(define-public gobject-introspection+cairo

(hidden-package

(package

(inherit gobject-introspection)

(arguments

(substitute-keyword-arguments (package-arguments

gobject-introspection)

((#:configure-flags flags ''())

`(cons* "-Dcairo=true" ,flags))))

(inputs

`(("cairo" ,cairo)

,@(package-inputs gobject-introspection))))))

```

Regards,

RG.

Hi John!

Or, something like this:

```

(define-public gobject-introspection+cairo

(hidden-package

(package

(inherit gobject-introspection)

(arguments

(substitute-keyword-arguments (package-arguments

gobject-introspection)

((#:configure-flags flags ''())

`(append

(list

"-Dcairo=true"

(string-append "-Dcairo_libname="

(assoc-ref %build-inputs "cairo")

"/lib/libcairo-gobject.so"))

,flags))))

(inputs

`(("cairo" ,cairo)

,@(package-inputs gobject-introspection))))))

```

Regards,

RG.