Help needed with gobject-introspection

Sun May 24 16:45:46 GMT 2020

On 5/24/2020 11:56 AM, Jon Turney wrote:
> On 21/05/2020 18:07, Ken Brown via Cygwin-apps wrote:
>> On 5/21/2020 11:48 AM, Jon Turney wrote:
>>> On 21/05/2020 16:13, Ken Brown via Cygwin-apps wrote:
>>>> On 5/21/2020 9:24 AM, Jon Turney wrote:
>>>>> On 20/05/2020 15:50, Ken Brown via Cygwin-apps wrote:
>>>>>> On 5/19/2020 7:04 PM, Ken Brown via Cygwin-apps wrote:
>>>>>>> I would like to adopt gimp and related packages.  At the moment I'm 
>>>>>>> having trouble with babl, which is needed for gegl0.4, which is needed 
>>>>>>> for gimp. The problem involves gobject-introspection.
>>>>>>>
>>>>>>> If I disable introspection, the build works fine.  This would be OK, 
>>>>>>> since babl has been built without introspection for several years. But 
>>>>>>> then the gegl0.4 build complains about the missing babl introspection 
>>>>>>> files, so I would have to disable introspection there too, which hasn't 
>>>>>>> been done in the past.
>>>>>>>
>>>>>>> So my preference is to figure out what the problem is and get the babl 
>>>>>>> build working with introspection.  I'm attaching my cygport file and patch.
>>>>>>>
>>>>>>> Here's the failing command...
>>>>>>>
>>>>>>> /usr/bin/g-ir-scanner -I/usr/include/gobject-introspection-1.0 
>>>>>>> -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -D_REENTRANT 
>>>>>>> --no-libtool --namespace=Babl --nsversion=0.1 --warn-all --output 
>>>>>>> babl/Babl-0.1.gir --c-include=babl.h 
>>>>>>> '--identifier-filter-cmd=/usr/bin/python3 
>>>>>>> /tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/babl/identfilter.py' 
>>>>>>> -DBABL_IS_BEING_COMPILED 
>>>>>>> -I/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/babl 
>>>>>>> -I/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl 
>>>>>>> -I./. -I../. -I./babl/base/. -I../babl/base/. 
>>>>>>> --filelist=/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl/4170c83@@babl-0.1@sha/Babl_0.1_gir_filelist 
>>>>>>> --cflags-begin -fno-unsafe-math-optimizations 
>>>>>>> -Wdeclaration-after-statement -Winit-self -Wmissing-declarations 
>>>>>>> -Wmissing-prototypes -Wold-style-definition -Wpointer-arith -mmmx -msse 
>>>>>>> -mfpmath=sse -I./. -I../. -I./babl/base/. -I../babl/base/. --cflags-end 
>>>>>>> --library babl-0.1 
>>>>>>> -L/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl 
>>>>>>> --extra-library=m --extra-library=dl --extra-library=lcms2
>>>>>>>
>>>>>>> ...and the error message:
>>>>>>>
>>>>>>> g-ir-scanner: link: gcc -o 
>>>>>>> /tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/tmp-introspectCwCaUc/Babl-0.1.exe 
>>>>>>> -ggdb -O2 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 
>>>>>>> -fstack-protector-strong --param=ssp-buffer-size=4 
>>>>>>> -fdebug-prefix-map=/tmp/cygbabl/babl-0.1.74-1.x86_64/build=/usr/src/debug/babl-0.1.74-1 
>>>>>>> -fdebug-prefix-map=/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74=/usr/src/debug/babl-0.1.74-1 
>>>>>>> /tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/tmp-introspectCwCaUc/Babl-0.1.o 
>>>>>>> -L. -lbabl-0.1 -lm -ldl -llcms2 
>>>>>>> -L/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl 
>>>>>>> -Wl,-rpath,/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl 
>>>>>>> -lgio-2.0 -lgobject-2.0 -Wl,--export-all-symbols -lgmodule-2.0 -lglib-2.0 
>>>>>>> -lintl
>>>>>>> ERROR: can't resolve libraries to shared libraries: babl-0.1
>>>>>>>
>>>>>>> I don't understand the error message, because the command line contains
>>>>>>>
>>>>>>> -L/tmp/cygbabl/babl-0.1.74-1.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/babl
>>>>>>>
>>>>>>> and that directory contains libbabl-0.1.dll.a and cygbabl-0.1-0.dll. I 
>>>>>>> even tried adding that directory to my PATH to make sure the right 
>>>>>>> cygbabl-0.1-0.dll would be found, but that didn't help.
>>>>>
>>>>> This might possibly be related to the problem described in the comment for:
>>>>>
>>>>> https://github.com/mesonbuild/meson/pull/2880/commits/8a27c08b05e4537d5061d30ddd8aad9dc52cf1c4 
> 
> 
> Yeah, this looks extremely plausible, there seem to be no GObject derived types 
> in babl's interface.
> 
> It might be possible to work around this by patching in a dummy GObject derived 
> type which does nothing.
> 
> I'll have to see if I can find my notes about how I debugged this before.
> 
>>>>>> By the way, in case you're wondering why I disabled the building of docs, 
>>>>>> it's because I was getting a build failure there too.  I don't know if 
>>>>>> this is related to the introspection failure.  The failing command there is
>>>>>>
>>>>>> /usr/bin/meson --internal exe --unpickle 
>>>>>> /tmp/cygbabl/babl-0.1.74-2.x86_64/src/babl-0.1.74/x86_64-pc-cygwin/meson-private/meson_exe_env_7bf39b99114d34540b83d26a5d8f097e05882836.dat 
>>>>>>
>>>>>> cp: target 'docs/index.html.tmp' is not a directory
>>>>>>
>>>>>> I don't know why it's not showing me the actual cp command that fails. 
>>>>>
>>>>> I believe it's is an infelicity in meson that it doesn't echo the actual 
>>>>> failing command here.
>>>>>
>>>>> Noted here: 
>>>>> https://github.com/mesonbuild/meson/pull/3716#issuecomment-395746838
>>>>>
>>>>>> The corresponding information in docs/meson.build is
>>>>>>
>>>>>> Reference_html = custom_target('Reference.html',
>>>>>>    input : [
>>>>>>      'Reference-static.html',
>>>>>>      'toc',
>>>>>>      index_html_tmp,
>>>>>>    ],
>>>>>>    output: [ 'Reference.html', ],
>>>>>>    command: [
>>>>>>      env_bin,
>>>>>>      'cp', '@INPUT0@', '@OUTPUT@',
>>>>>>      '&&', xml_insert, '@OUTPUT@', 'TOC', '@INPUT1@',
>>>>>>      '&&', xml_insert, '@OUTPUT@', 'BablBase', '@INPUT2@',
>>>>>>    ],
>>>>>>    build_by_default: true,
>>>>>> )
>>>>>>
>>>>>> There are several such custom targets in the file, and for all except this 
>>>>>> one, I see the actual cp command in the log.  This is the only one for 
>>>>>> which meson generates a 'meson --unpickle' command instead of a cp command.
>>>>>
>>>>> Yeah, I wasn't expecting it to use this method of executing the command 
>>>>> line (storing it in a pickle and then using a python wrapper to execute it) 
>>>>> to be used except on Windows, so I'll have to take a more detailed look at 
>>>>> why that's happening.
> 
> So, it's correct that it runs this command indirectly via the pickle, because it 
> needs to interpose itself to do some PATH manipulation to add the DLL, because 
> this target has the 'babl-html-dump' tool, which is linked with the DLL, in it's 
> input (indirectly).
> 
>>>> Thanks.  FWIW, the recipe for building docs/Reference.html translates to
>>>>
>>>>    /usr/bin/env \
>>>>       cp ../docs/Reference-static.html docs/Reference.html \
>>>>        && ../docs/tools/xml_insert.sh docs/Reference.html TOC ../docs/toc \
>>>>        && ../docs/tools/xml_insert.sh \
>>>>           docs/Reference.html BablBase docs/index.html.tmp
>>>>
>>>> This succeeds when run manually in the build directory.  So something must 
>>>> have gone wrong in the pickling/unpickling process.
>>>
>>>
>>> patching /usr/lib/python3.6/site-packages/mesonbuild/scripts/meson_exe.py 
>>> something like this might shed some light:
>>>
>>> --- meson_exe.py.bak    2020-05-21 15:01:19.187046500 +0100
>>> +++ meson_exe.py        2020-05-21 15:09:29.485915300 +0100
>>> @@ -57,6 +57,8 @@
>>>                   ['Z:' + p for p in exe.extra_paths] + 
>>> child_env.get('WINEPATH', '').split(';')
>>>               )
>>>
>>> +    print(cmd_args)
>>> +
>>>       p = subprocess.Popen(cmd_args, env=child_env, cwd=exe.workdir,
>>>                            close_fds=False,
>>>                            stdout=subprocess.PIPE,
>>
>> OK, now the log shows
>>
>> cp: target 'docs/index.html.tmp' is not a directory
>> ['/usr/bin/env', 'cp', '../docs/Reference-static.html', 'docs/Reference.html', 
>> '&&', 
>> '/home/kbrown/src/cygpackages/babl/babl-0.1.74-1.x86_64/src/babl-0.1.74/docs/tools/xml_insert.sh', 
>> 'docs/Reference.html', 'TOC', '../docs/toc', '&&', 
>> '/home/kbrown/src/cygpackages/babl/babl-0.1.74-1.x86_64/src/babl-0.1.74/docs/tools/xml_insert.sh', 
>> 'docs/Reference.html', 'BablBase', 'docs/index.html.tmp']
>>
>> This does indeed shed some light.  If I remove all the commas but leave the 
>> single quotes, the command fails with the same error message as before:
>>
>> cp: target 'docs/index.html.tmp' is not a directory
>>
>> If I also remove the single quotes, the command succeeds.  I think the problem 
>> is the quotes around the double ampersands, so they are treated as arguments 
>> to the cp command instead of being interpreted by the shell executing the 
>> command.
> 
> So, yeah, this is a meson bug, which I will work on (if this command ends up in 
> the build.ninja, it's executed by ninja with 'sh -c', but if it ends up in a 
> pickle, it's executed by meson with execve())

Yes, that does seem like a meson bug.  But is it also a babl bug to some extent? 
  When babl puts '&&' in a command argument, it's assuming that the command will 
be executed by 'sh -c'.

I have very little experience with meson.  Have you ever seen this issue in 
other projects that use meson?

> (Ofc, everything behaves differently if we are building on Windows, and 
> CreateProcess() is used in both places, so allowing shell control operators here 
> is not very portable)