Re: [gtk-osx-users] Need to explicitly export DYLD_FALLBACK_LIBRARY_PATH

[John Ralls <jralls ceridwen us>]

> On Sep 28, 2019, at 3:20 AM, Timo via gtk-osx-users-list <gtk-osx-users-list gnome org> wrote:
>
> Hello, I followed the build instructions on the wiki and everything's built correctly. However my 
> application fails to run with a warning about libpango-1.0.0.dylib not being found and then a traceback. I 
> can narrow it down to just doing a `from gi.repository import Gtk`.
>
>     bash-3.2$ python3
>     Python 3.6.8 (default, Sep 24 2019, 17:23:22)
>     [GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)] on darwin
>     Type "help", "copyright", "credits" or "license" for more information.
>     >>> from gi.repository import Gtk
>
>     ** (process:45468): WARNING **: 20:30:34.767: Failed to load shared library 'libpango-1.0.0.dylib' 
> referenced by the typelib: dlopen(libpango-1.0.0.dylib, 9): image not found
>     Traceback (most recent call last):
>       File "<stdin>", line 1, in <module>
>       File "<frozen importlib._bootstrap>", line 971, in _find_and_load
>       File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
>       File "<frozen importlib._bootstrap>", line 656, in _load_unlocked
>       File "<frozen importlib._bootstrap>", line 626, in _load_backward_compatible
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/importer.py", line 145, in load_module
>         importlib.import_module('gi.repository.' + dep.split("-")[0])
>       File "/Users/gtk3/gtk/inst/lib/python3.6/importlib/__init__.py", line 126, in import_module
>         return _bootstrap._gcd_import(name[level:], package, level)
>       File "<frozen importlib._bootstrap>", line 994, in _gcd_import
>       File "<frozen importlib._bootstrap>", line 971, in _find_and_load
>       File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
>       File "<frozen importlib._bootstrap>", line 656, in _load_unlocked
>       File "<frozen importlib._bootstrap>", line 626, in _load_backward_compatible
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/importer.py", line 145, in load_module
>         importlib.import_module('gi.repository.' + dep.split("-")[0])
>       File "/Users/gtk3/gtk/inst/lib/python3.6/importlib/__init__.py", line 126, in import_module
>         return _bootstrap._gcd_import(name[level:], package, level)
>       File "<frozen importlib._bootstrap>", line 994, in _gcd_import
>       File "<frozen importlib._bootstrap>", line 971, in _find_and_load
>       File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
>       File "<frozen importlib._bootstrap>", line 656, in _load_unlocked
>       File "<frozen importlib._bootstrap>", line 626, in _load_backward_compatible
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/importer.py", line 146, in load_module
>         dynamic_module = load_overrides(introspection_module)
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/overrides/__init__.py", line 118, in 
> load_overrides
>         override_mod = importlib.import_module(override_package_name)
>       File "/Users/gtk3/gtk/inst/lib/python3.6/importlib/__init__.py", line 126, in import_module
>         return _bootstrap._gcd_import(name[level:], package, level)
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/overrides/Pango.py", line 41, in <module>
>         FontDescription = override(FontDescription)
>       File "/Users/gtk3/gtk/inst/lib/python3.6/site-packages/gi/overrides/__init__.py", line 195, in 
> override
>         assert g_type != TYPE_NONE
>     AssertionError
>
>
> Explicitly setting DYLD_FALLBACK_LIBRARY_PATH seems to fix the problem:
>
>     bash-3.2$ export DYLD_FALLBACK_LIBRARY_PATH=/Users/gtk3/gtk/inst/lib
>     bash-3.2$ python3
>     Python 3.6.8 (default, Sep 24 2019, 17:23:22)
>     [GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)] on darwin
>     Type "help", "copyright", "credits" or "license" for more information.
>     >>> from gi.repository import Gtk
>
>     (.:45493): Gtk-WARNING **: 20:33:47.938: Locale not supported by C library.
>         Using the fallback 'C' locale.
>     __main__:1: PyGIWarning: Gtk was imported without specifying a version first. Use 
> gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
>
>
> However the same problem happens when I bundle the application. Again, only doing the GTK import in the 
> myapp_launcher.py file gives the same error (launcher file taken from gtk-mac-bundler example and Gramps 
> for the updated version).
>
> It already has `environ['DYLD_LIBRARY_PATH'] = bundle_lib`, but even adding 
> `environ['DYLD_FALLBACK_LIBRARY_PATH'] = bundle_lib` makes no differences. Printing `bundle_lib` points to 
> the lib dir inside the bundle and printing `os.path.exists(bundle_lib, 'libpango-1.0.0.dylib')` shows the 
> file is actually there. So it's not picking up the Python set env variable.
>
> It's only after I do `export DYLD_FALLBACK_LIBRARY_PATH=/path/to/myapp_bundle.app/Contents/Resources/lib` 
> that the bundled app will run, but is of course only feasible to do on my dev machine.
>
> Is it my environment that's tainted somehow? Did the build not correctly pick up paths?

It mostly has to do with meson and rpaths. The latest commit to gtk-mac-bundler, 
https://gitlab.gnome.org/GNOME/gtk-mac-bundler/commit/93edee7e2d0ec8230aaf5acb21452202b10cd678, was supposed 
to fix it, but meson's behavior has been something of a moving target.

What are the installed names (use otool -L and look at the first line) of libpango-1.0.0.dylib in your 
installed prefix and in your bundle?

What version of meson did pip install for you?

Regards,
John Ralls