Choosing correct glib version

[jhutchins]

For some reason that I can't seem to figure out, my project with a transitive dependency on glib-sys keeps try to build against version 2.70 of glib-2.0 even though the greatest version on my system is 2.66.8. The exact error is

warning: `"pkg-config" "--libs" "--cflags" "glib-2.0" "glib-2.0 >= 2.70"` did not exit successfully: exit status: 1

error: failed to run custom build command for `glib-sys v0.16.3`

Caused by:
  process didn't exit successfully: `/code/target/debug/build/glib-sys-cf43a4274fe6d4b2/build-script-build` (exit status: 1)
  --- stdout
  cargo:rerun-if-env-changed=GLIB_2.0_NO_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
  cargo:warning=`"pkg-config" "--libs" "--cflags" "glib-2.0" "glib-2.0 >= 2.70"` did not exit successfully: exit status: 1
  error: could not find system library 'glib-2.0' required by the 'glib-sys' crate

  --- stderr
  Requested 'glib-2.0 >= 2.70' but version of GLib is 2.66.8

I assume there's some way to pin the version and that maybe it has something to do with the system-deps package, but I don't really know how. Any help would be much appreciated.

[sdroege]

That means that something depends on the glib or glib-sys crate in your project with feature v2_70. This implies that version 2.70 of the GLib C library is required.

[jhutchins]

After digging through the dependency tree for a bit it looks like the v2_70 feature dependency is coming from soup3 v0.3.2 as can be seen in this pruned dependency tree.

soup3 v0.3.2
├── gio feature "v2_70"
│   ├── gio v0.16.7 (*)
│   ├── glib feature "v2_70"
│   │   ├── glib v0.16.7 (*)
│   │   ├── glib feature "v2_68"
│   │   │   ├── glib v0.16.7 (*)
│   │   │   ├── glib feature "v2_66" (*)
│   │   │   ├── glib-sys feature "v2_68"
│   │   │   │   ├── glib-sys v0.16.3 (*)
│   │   │   │   └── glib-sys feature "v2_66" (*)
│   │   │   └── gobject-sys feature "v2_68"
│   │   │       ├── gobject-sys v0.16.3 (*)
│   │   │       └── gobject-sys feature "v2_66" (*)
│   │   ├── glib-sys feature "v2_70"
│   │   │   ├── glib-sys v0.16.3 (*)
│   │   │   └── glib-sys feature "v2_68" (*)
│   │   └── gobject-sys feature "v2_70"
│   │       ├── gobject-sys v0.16.3 (*)
│   │       └── gobject-sys feature "v2_68" (*)
├── glib feature "v2_66"
│   ├── glib v0.16.7 (*)
│   ├── glib feature "v2_64"
│   │   ├── glib v0.16.7 (*)
│   │   ├── glib feature "v2_62"
│   │   │   ├── glib v0.16.7 (*)
│   │   │   ├── glib feature "v2_60"
│   │   │   │   ├── glib v0.16.7 (*)
│   │   │   │   ├── glib feature "v2_58"
│   │   │   │   │   ├── glib v0.16.7 (*)
│   │   │   │   │   ├── glib-sys feature "v2_58"
│   │   │   │   │   │   └── glib-sys v0.16.3 (*)
│   │   │   │   │   └── gobject-sys feature "v2_58"
│   │   │   │   │       └── gobject-sys v0.16.3 (*)
│   │   │   │   └── glib-sys feature "v2_60"
│   │   │   │       ├── glib-sys v0.16.3 (*)
│   │   │   │       └── glib-sys feature "v2_58" (*)
│   │   │   ├── glib-sys feature "v2_62"
│   │   │   │   ├── glib-sys v0.16.3 (*)
│   │   │   │   └── glib-sys feature "v2_60" (*)
│   │   │   └── gobject-sys feature "v2_62"
│   │   │       ├── gobject-sys v0.16.3 (*)
│   │   │       └── gobject-sys feature "v2_58" (*)
│   │   └── glib-sys feature "v2_64"
│   │       ├── glib-sys v0.16.3 (*)
│   │       └── glib-sys feature "v2_62" (*)
│   ├── glib-sys feature "v2_66"
│   │   ├── glib-sys v0.16.3 (*)
│   │   └── glib-sys feature "v2_64" (*)
│   └── gobject-sys feature "v2_66"
│       ├── gobject-sys v0.16.3 (*)
│       └── gobject-sys feature "v2_62" (*)

I find it interesting that while soup3 defines it's own dependency on glib as requiring feature v2_66 it brings in the v2_70 feature anyways because of its gio dependency.

[sdroege]

Ok, that makes sense I guess