Re: Help needed with gobject-introspection

[Jon Turney <jon.turney@dronecode.org.uk>]

On 06/06/2020 15:15, Ken Brown via Cygwin-apps wrote:
> 
> I think I might have bumped into another meson/introspection/pickling 
> bug, this time in connection with harfbuzz.  The supported build system 
> for harfbuzz is still autotools.  But they're planning to move to meson, 
> so I decided to get a head start and try the meson build, which fails as 
> follows:
> 
> [230/257] Generating HarfBuzz-0.0.gir with a meson_exe.py custom command
> FAILED: src/HarfBuzz-0.0.gir
> /usr/bin/meson --internal exe --unpickle 
> /tmp/harfbuzz-2.6.7/build/meson-private/meson_exe_g-ir-scanner_2a1d762c64dc7a0dcba76211733b53a4f7f14918.dat 
> 
> [...]
> ERROR: can't resolve libraries to shared libraries: harfbuzz-gobject
> g-ir-scanner: link: cc -o 
> /tmp/harfbuzz-2.6.7/build/tmp-introspectKdIYKJ/HarfBuzz-0.0.exe 
> /tmp/harfbuzz-2.6.7/build/tmp-introspectKdIYKJ/HarfBuzz-0.0.o -L. 
> -lharfbuzz -lharfbuzz-gobject -lm -lglib-2.0 -lintl -lgobject-2.0 
> -lcairo -lfreetype -lgraphite2 -lfontconfig 
> -L/tmp/harfbuzz-2.6.7/build/src -Wl,-rpath,/tmp/harfbuzz-2.6.7/build/src 
> -L/tmp/harfbuzz-2.6.7/build/src -Wl,-rpath,/tmp/harfbuzz-2.6.7/build/src 
> -L/tmp/harfbuzz-2.6.7/build/src -Wl,-rpath,/tmp/harfbuzz-2.6.7/build/src 
> -lgio-2.0 -lgobject-2.0 -Wl,--export-all-symbols -lgmodule-2.0 
> -lglib-2.0 -lintl
[...]

Thanks for the reproduction steps.

To debug: hack meson to get it to disgorge the pickled command it's 
executing, then you can run the failing g-ir-scanner command line while 
poking at things in /usr/lib/gobject-introspection/giscanner/

This actually looks like a bug in 'g-ir-scanner --no-libtool' (which 
obviously isn't usually exercised by an autotools build), failing in 
this particular case.

It looks to match the following list of regexes:

> ([^\s]*cyg*harfbuzz[^A-Za-z0-9_][^\s\(\)]*)
> ([^\s]*cyg*harfbuzz\-gobject[^A-Za-z0-9_][^\s\(\)]*)

against ldd output like this, to extract the shared library names:

>         ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ff916d80000)
>         KERNEL32.DLL => /cygdrive/c/WINDOWS/System32/KERNEL32.DLL (0x7ff916660000)
>         KERNELBASE.dll => /cygdrive/c/WINDOWS/System32/KERNELBASE.dll (0x7ff914a20000)
>         cyggmodule-2.0-0.dll => /usr/bin/cyggmodule-2.0-0.dll (0x3e0590000)
>         cygwin1.dll => /usr/bin/cygwin1.dll (0x180040000)
>         cygharfbuzz-gobject-0.dll => /work/harfbuzz-2.6.7/_build/src/cygharfbuzz-gobject-0.dll (0x4389e0000)
>         cyggio-2.0-0.dll => /usr/bin/cyggio-2.0-0.dll (0x3e0f40000)
>         cygglib-2.0-0.dll => /usr/bin/cygglib-2.0-0.dll (0x3e0870000)
>         cyggobject-2.0-0.dll => /usr/bin/cyggobject-2.0-0.dll (0x3dff50000)
>         cygharfbuzz-0.dll => /work/harfbuzz-2.6.7/_build/src/cygharfbuzz-0.dll (0x4408d0000)
>         cygintl-8.dll => /usr/bin/cygintl-8.dll (0x3cf150000)
>         cygz.dll => /usr/bin/cygz.dll (0x3bc750000)
>         cygiconv-2.dll => /usr/bin/cygiconv-2.dll (0x3dbec0000)
>         cygpcre-1.dll => /usr/bin/cygpcre-1.dll (0x4629a0000)
>         cygffi-6.dll => /usr/bin/cygffi-6.dll (0x3e3fd0000)
>         cyggcc_s-seh-1.dll => /usr/bin/cyggcc_s-seh-1.dll (0x50caa0000)
>         cygfreetype-6.dll => /usr/bin/cygfreetype-6.dll (0x451720000)
>         cyggraphite2-3.dll => /usr/bin/cyggraphite2-3.dll (0x5f6ba0000)
>         cygbz2-1.dll => /usr/bin/cygbz2-1.dll (0x3e9980000)
>         cygpng16-16.dll => /usr/bin/cygpng16-16.dll (0x3c58d0000)
>         cygstdc++-6.dll => /usr/bin/cygstdc++-6.dll (0x57b190000)

Unfortunately, the first regex matches the cygharfbuzz-gobject line, 
leaving the second regex unmatched.

We have to allow a '-' to appear after the library name, as that 
introduces a soversion, so I worked around this by patching 
/usr/lib/gobject-introspection/giscanner/shlibs.c like this:

--- shlibs.py~  2018-02-11 23:15:03.000000000 +0000
+++ shlibs.py   2020-06-11 22:28:07.901294700 +0100
@@ -62,7 +62,7 @@
      if platform.system() == 'Darwin':
          pattern = "([^\s]*lib*%s[^A-Za-z0-9_-][^\s\(\)]*)"
      elif platform.platform().startswith('CYGWIN'):
-        pattern = "([^\s]*cyg*%s[^A-Za-z0-9_][^\s\(\)]*)"
+        pattern = "([^\s]*cyg%s[-.0-9]*\.[^\s\(\)]*)"
      return re.compile(pattern % re.escape(library_name))

But this all seems very fragile though, so I'm not sure if that's the 
right way to fix this.

(This 'if cygwin' case is coming from gobject-introspection package in 
[1], it's not in upstream)

https://cygwin.com/git-cygwin-packages/?p=git/cygwin-packages/gobject-introspection.git;a=blob;f=1.46.0-cygwin.patch;h=a03271ea17e0d167eba7627ddf5d4303bbde9871;hb=4e3b8bd140db78ee35f29ee3d07ff3715416e259#l93