cmake does not work well with ccache

[Vladislav Vaintroub]

Binary package hint: cmake

Using Ubuntu 11.04, trying to use CMake with ccache via
export CC='ccache gcc'
export CXX='ccache g++'

results in a lot (once per system check) of output like below during cmake run. It looks like ccache was invoked with wrong parameter . If I use compiled cmake 2.8.4 from source , this does not happen.

Output
-- Check for working CXX compiler: /usr/bin/ccache
/usr/bin/ccache: invalid option -- 'd'
Usage:
    ccache [options]
    ccache compiler [compiler options]
    compiler [compiler options] (via symbolic link)

Options:
    -c, --cleanup delete old files and recalculate size counters
                          (normally not needed as this is done automatically)
    -C, --clear clear the cache completely
    -F, --max-files=N set maximum number of files in cache to N (use 0 for
                          no limit)
    -M, --max-size=SIZE set maximum size of cache to SIZE (use 0 for no
                          limit; available suffixes: G, M and K; default
                          suffix: G)
    -s, --show-stats show statistics summary
    -z, --zero-stats zero statistics counters

    -h, --help print this help text
    -V, --version print version and copyright information

See also <http://ccache.samba.org>.
dpkg-architecture: warning: Couldn't determine gcc system type, falling back to default (native compilation)

[Rico Zoss (rico.zoss)]

I can confirm this bug. Compiling the newest veriosn of cmake (2.8.4) solve the problem.

[Eddy Pronk (epronk)]

Ironically ccache is a workaround for broken build systems.

[Harald Sitter (apachelogger)]

<apachelogger> ScottK: that cmake bug looks like fun btw
<apachelogger> also I do not think it is a cmake issue at all
<apachelogger> or perhaps it is, but only partially
<apachelogger> in particular it is probably falling over the fact that cxx has a cmd and a arg, which generally speaking of course is a bit of a bogus situation
<apachelogger> yeah
<apachelogger> gcc got three args with -d
<apachelogger> cmake does not call either
-*- apachelogger runs cmake with tracing
<apachelogger> /usr/share/cmake-2.8/Modules/Platform/UnixPaths.cmake(32): EXECUTE_PROCESS(COMMAND dpkg-architecture -qDEB_HOST_MULTIARCH OUTPUT_VARIABLE CMAKE_ARCH_TRIPLET OUTPUT_STRIP_TRAILING_WHITESPACE )
<apachelogger> Called from: [4] /usr/share/cmake-2.8/Modules/Platform/UnixPaths.cmake
<apachelogger> [3] /usr/share/cmake-2.8/Modules/Platform/Linux.cmake
<apachelogger> [2] /usr/share/cmake-2.8/Modules/CMakeSystemSpecificInformation.cmake
<apachelogger> [1] /home/me/src/git/libechonest/CMakeLists.txt
<apachelogger> /usr/bin/ccache: invalid option -- 'd'
<apachelogger> 5 bucks that call comes from a patch
<apachelogger> me@osiris:/tmp/cmake-2.8.4+dfsg.1$ grep -ri dpkg-architecture .
<apachelogger> ./debian/patches/ubuntu_multiarch_library_directory.diff:+EXECUTE_PROCESS(COMMAND dpkg-architecture -qDEB_HOST_MULTIARCH OUTPUT_VARIABLE CMAKE_ARCH_TRIPLET OUTPUT_STRIP_TRAILING_WHITESPACE)
<debfx> what's wrong with it?
<apachelogger> well, it causes ccache -dumpmachine to be called
<apachelogger> leading to an eror in ccache
<apachelogger> as obviously the call should be ccache gcc -dumpinfo
<apachelogger> eh
<apachelogger> dumpmachine
<apachelogger> debfx: perhaps the patch was applied differently upstream?
<debfx> how does ccache hook into the buildsystem? does it modify $PATH?
<apachelogger> no
<apachelogger> you set a new CXX and CC env var
<apachelogger> debfx: multiarch is something gcc, that should totally be implemented in cmake upstream
<apachelogger> anyhow
<apachelogger> for some reason dpkg-architecture calls:
<apachelogger> execve("/bin/sh", ["sh", "-c", "${CC:-gcc} -dumpmachine"], [/* 50 vars */]) = 0
<apachelogger> resulting in
<apachelogger> execve("/usr/bin/ccache", ["/usr/bin/ccache", "-dumpmachine"], [/* 50 vars */]) = 0
<apachelogger> which then produces crap outs
<apachelogger> I believe cmake pokes the env around a bit
<apachelogger> I know that it definitely stores CC/CXX as a combo of command + argN
<apachelogger> so if cmake were to set its envrionemnt so that CC only contains the command and no the arg (which is generally sane behaviour I suppose), that would screw over the poor old dpkg-architecture

[Harald Sitter (apachelogger)]

Thus I do not think we can SRU this, as it is not even quite sure which tool actually screws up, nor which part of that tool.

[Felix Geyer (debfx)]

Fixed in oneiric as the new multiarch patch doesn't call dpkg-architecture anymore.