py2app TypeError: dyld_find() got an unexpected keyword argument 'loader'

Question

I'm having difficulty building my app using py2app. I can build it in alias mode without issue using this command:

python3.4 setup.py py2app -A

However when I try and build it using:

python3.4 setup.py py2app

I get the error message as per title of this post. From the research I've done I believe it's an issue with Pillow; however I need Pillow for this app. (Unless there's another module I can use to import images??). I've also tried cx_freeze without success.

Any help or direction much appreciated.

Full traceback as follows:

Traceback (most recent call last):
File "setup.py", line 19, in <module>
setup_requires=['py2app'],
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
distutils/core.py", line 148, in setup dist.run_commands()
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
distutils/dist.py", line 955, in run_commands self.run_command(cmd)
File"/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
distutils/dist.py", line 974, in run_command cmd_obj.run()
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-  packages/py2app/build_app.py", line 659, in run self._run()
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site- packages/py2app/build_app.py", line 865, in _run self.run_normal()
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site- packages/py2app/build_app.py", line 959, in 
run_normal self.create_binaries(py_files, pkgdirs, extensions,loader_files)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site- packages/py2app/build_app.py", line 1214, in create_binaries
platfiles = mm.run()
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOStandalone.py", line 105, in run
mm.run_file(fn)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOGraph.py", line 84, in run_file
self.scan_node(m)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOGraph.py", line 110, in scan_node 
m =  self.load_file(filename, caller=node)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOGraph.py", line 93, in load_file
newname = self.locate(name, loader=caller)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOStandalone.py", line 23, in locate
newname = super(FilteredMachOGraph, self).locate(filename, loader)
File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/
site-packages/macholib/MachOGraph.py", line 49, in locate
loader=loader.filename)
TypeError: dyld_find() got an unexpected keyword argument 'loader'

Answer 1

This is a temporary solution, and it may break other things. I would recommend doing this is a virtual environment so you don't mess up your regular packages. This worked for me (virtenv is the name of my virtual environment)

Open the file /virtenv/lib/python3.4/site-packages/macholib/dyld.py and replace each instance of loader_path with loader. Now save and try again.

Answer 2

You can monkey-patch macholib rather than modifying it in site-packages. Place the following file to the directory containing setup_py2app.py and add import macholib_patch to the top.

macholib_patch.py:

"""
Monkey-patch macholib to fix "dyld_find() got an unexpected keyword argument 'loader'".

Add 'import macholib_patch' to the top of set_py2app.py
"""

import macholib
#print("~"*60 + "macholib verion: "+macholib.__version__)
if macholib.__version__ <= "1.7":
    print("Applying macholib patch...")
    import macholib.dyld
    import macholib.MachOGraph
    dyld_find_1_7 = macholib.dyld.dyld_find
    def dyld_find(name, loader=None, **kwargs):
        #print("~"*60 + "calling alternate dyld_find")
        if loader is not None:
            kwargs['loader_path'] = loader
        return dyld_find_1_7(name, **kwargs)
    macholib.MachOGraph.dyld_find = dyld_find