Bad includes generated by snapcraft scons plugin

[Mark Shuttleworth]

This part fails to build:

  gpsd:
    plugin: scons
    source: http://download-mirror.savannah.gnu.org/releases/gpsd/gpsd-3.16.tar.gz
    scons-options: [ prefix=/usr/, python=no, qt=no ]
    stage-packages: [ libncurses5-dev, libtinfo-dev ]

The final error is this:

gcc -o ais_json.os -c -I/home/mark/software/timesink/parts/gpsd/install/usr/include -I/home/mark/software/timesink/parts/gpsd/install/usr/include/x86_64-linux-gnu -Wextra -Wall -Wno-uninitialized -Wno-missing-field-initializers -Wcast-align -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wpointer-arith -Wreturn-type -pthread -Wmissing-declarations -O2 -fPIC " -I/home/mark/software/timesink/parts/gpsd/install/usr/include -I/home/mark/software/timesink/parts/gpsd/install/usr/include/x86_64-linux-gnu" ais_json.c

And the issue appears to be the " " around the double -I sections, which make GCC think that there is supposed to be a file called " -I ... -I ..."

[Sergio Schvezov (sergiusens)]

We export include directories for the staging area and staged packages (from `stage-packages`) to allow building this. What we do is for CPPFLAGS, CFLAGS and CXXFLAGS is to add -I directives for the canonical include directories which are on non standard paths.

It seems the SConstruct file for gpsd treats CPPFLAGS differently:

- SConstruct:261 for CFLAGS
- SConstruct:265 for CPPFLAGS

Where the former does a proper split while the latter does a plain join. Given that CPPFLAGS is really the proper way to declare includes (and we use the others for some compatibility with a plethora of build systems) I feel reluctant to just remove CPPFLAGS here.

That said, to unblock you quickly you can change those `stage-packages` to `build-packages`

Does my assessment sound fair?

[Mark Shuttleworth (sabdfl)]

Well, somehow Scons is ending up telling GCC to '"-I X -I Y"' (note the
double set of quotes). That's a bug :)

I bet if the "" were removed it would work. I just don't know where in
the stack it's coming from.

Mark

[Sergio Schvezov (sergiusens)]

El 06/06/16 a las 16:42, Mark Shuttleworth escribió:
> Well, somehow Scons is ending up telling GCC to '"-I X -I Y"' (note the
> double set of quotes). That's a bug :)
>
> I bet if the "" were removed it would work. I just don't know where in
> the stack it's coming from.

The SConstruct file is part of gpsd's source code.
The current sources you are using have:
        env.MergeFlags({flag : [os.getenv(flag)]})

I just checked upstream's latest and greatest[1] and I see it seems to
have been corrected:
        env.MergeFlags({flag: Split(os.getenv(flag))})

So I rolled in the git tree as a source, replacing the tarball, and it
all works fine.

I am marking this invalid, if you feel that is wrong, feel free to
reopen it. But the fact is, we are just passing an envvar of the form
CLFAGS="$CFLAGS -I/usr/include -I/usr/include/..." and the SConstruct
was grabbing that envvar incorrectly.

[1] http://git.savannah.gnu.org/cgit/gpsd.git/tree/SConstruct#n311

[Mark Shuttleworth (sabdfl)]

Perfect, thank you!