CMake 3.5's pkg-config support broken

[Michał Sawicz]

With the new cmake 3.5 version in xenial, pkg-config variables seem broken.

Given the following CMakeLists.txt:

cmake_minimum_required(VERSION 3.2)
include(FindPkgConfig)
pkg_check_modules(GLIB2 glib-2.0)

Comparing output from:

$ cmake .; grep ^GLIB2 CMakeCache.txt

Yields the _INCLUDEDIR, _LIBDIR and _PREFIX variables empty: http://pastebin.ubuntu.com/15555106/

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: cmake 3.5.0-1ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-15.31-generic 4.4.6
Uname: Linux 4.4.0-15-generic x86_64
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Mar 29 22:47:54 2016
SourcePackage: cmake
UpgradeStatus: No upgrade log present (probably fresh install)

[Steve Langasek (vorlon)]

This is fallout from a post-beta merge of a new upstream version of cmake.

A feature freeze exception of a core build tool is altogether unreasonable. When it introduces regressions, it is unacceptable.

I have communicated to Michał and Gianfranco on IRC that if this issue is not resolved by my end of day, I intend to revert the merge, which clearly did not receive adequate testing.

[Michał Sawicz (saviq)]

Just confirming that the 3.5.0-1ubuntu2 upload doesn't help unfortunately.

Note cmake-extras needs to be rebuilt again (no-change) if cmake will get reverted (yes, we need to come up with some better packaging there - at least appropriately versioned dependencies on cmake).

[Gianfranco Costamagna (costamagnagianfranco)]

hotfix for the bug.

[Gianfranco Costamagna (costamagnagianfranco)]

the package is building on my ppa https://launchpad.net/~costamagnagianfranco/+archive/ubuntu/costamagnagianfranco-ppa

BTW I honestly think this was a typo in the set variable.
Probably a change like
+- _pkgconfig_set("${_pkg_check_modules_pkg}_${variable}" "${${_pkg_check_modules_pkg}_${variable}}")
++ _pkgconfig_set("${_pkg_check_prefix}_${variable}" "${${_pkg_check_prefix}_${variable}}")

is already enough.
Having them both results in something like:

GLIB2_INCLUDEDIR:INTERNAL=/usr/include
GLIB2_LIBDIR:INTERNAL=/usr/lib/x86_64-linux-gnu
GLIB2_PREFIX:INTERNAL=/usr

and

glib-2.0_INCLUDEDIR:INTERNAL=/usr/include
glib-2.0_LIBDIR:INTERNAL=/usr/lib/x86_64-linux-gnu
glib-2.0_PREFIX:INTERNAL=/usr

I think we could have just the former version.

[Dirk Thomas (dthomas-b)]

Only variables started with the passed prefix (in this case `GLIB2`) should be set. I don't think the variables starting with `glib-2.0_` should be set.

[Gianfranco Costamagna (costamagnagianfranco)]

yes, it was enough, and the patch was already upstreamed.
https://anonscm.debian.org/cgit/pkg-cmake/cmake.git/commit/?id=b71943bca4ed372568050d460960764ca2b3d4aa

[Dirk Thomas (dthomas-b)]

The upstream code in the tarball for version 3.5.1 (https://cmake.org/files/v3.5/cmake-3.5.1.tar.gz) looks as follows:

foreach (variable IN ITEMS PREFIX INCLUDEDIR LIBDIR)
  _pkgconfig_set("${_pkg_check_prefix}_${variable}" "${${_pkg_check_prefix}_${variable}}")
endforeach ()

The fix was introduced upstream in https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=6f4f9054 and is mentioned in the last comment in this ticket: https://public.kitware.com/Bug/view.php?id=15903

Maybe this should be updated to use 3.5.1 which seems to have fixed that problem already?

[Gianfranco Costamagna (costamagnagianfranco)]

please followup on https://bugs.launchpad.net/ubuntu/+source/cmake/+bug/1563580

[Launchpad Janitor (janitor)]

This bug was fixed in the package cmake - 3.5.0-1ubuntu3

---------------
cmake (3.5.0-1ubuntu3) xenial; urgency=medium

  * Fix FindPkgModules.cmake (LP: #1563548)
    seems that a typo was preventing the correct internal variables from being set.

 -- Gianfranco Costamagna <email address hidden> Wed, 30 Mar 2016 00:19:04 +0200