Workaround for setuptools distribution autodiscovery

This introduces a ``setuptools.finalize_distribution_options``
that sets the *name* and *py_modules* attributes of the
distribution in a way that is compatible with py2app's regular
calculation of these attributes.

This avoid problems with setuptools 61.0.0 or later that
use autodiscovery to set these attributes to values that may
not be compatible with py2app.

Issue #414

doc/changelog.rst

@@ -4,20 +4,25 @@ Release history
 py2app 0.28
 -----------
 
-.. warning:: incompatibility with setuptools 61.0
+* #414 Workaround for autodiscovery in setuptools 61.0
 
-   Setuptools 61.0 introduces autodiscovery of distribution
-   attributes, and this might affect users of py2app. Two
-   related error scenario's are:
+  Setuptools 61.0 introduces autodiscovery of distribution
+  attributes, and that broke py2app. This version introduces
+  a ``setuptools.finalize_distribution_options`` entrypoint 
+  in py2app that will set the distributions's *name* and
+  *py_modules* attributes in a way that is compatible with 
+  the main code of py2app when they are not yet set (before
+  autodiscovery kicks in).
 
-   - The name of the generated application is not based on
-     the script name, but some other value.
+  In older versions of py2app buildin an app can fail in two
+  ways with setuptools 61.0 or later:
 
-   - Calling ``python setup.py py2app`` results in an error
-     mentioning ``Multiple top-level modules discovered``.
+  - The name of the generated application is not based on
+    the script name, but some other value.
+
+  - Calling ``python setup.py py2app`` results in an error
+    mentioning ``Multiple top-level modules discovered``.
 
-   To disable autodiscovery by setuptools update the setup.py
-   file and add ``name=`` and ``py_modules=[]`` to the call to setup().
 
 * PR #418: Add recipe for black
 

py2app/build_app.py

@@ -90,6 +90,36 @@
 else:
     sys_base_prefix = sys.prefix
 
+def finalize_distribution_options(dist):
+    """
+    setuptools.finalize_distribution_options extension
+    point for py2app, to deail with autodiscovery in
+    setuptools 61.
+
+    This addin will set the name and py_modules attributes
+    when a py2app distribution is detected that does not 
+    yet have these attributes.
+    are not already set
+    """
+    if (getattr(dist, "app", None) is None and
+        getattr(dist, "plugin", None) is None):
+        return
+
+    if getattr(dist.metadata, "py_modules", None) is None:
+        dist.py_modules = []
+
+    name = getattr(dist.metadata, "name", None)
+    if name is None or name == "UNKNOWN":
+        if dist.app:
+            targets = FixupTargets(dist.app, "script")
+        else:
+            targets = FixupTargets(dist.plugin, "script")
+
+        base = targets[0].get_dest_base()
+        name = os.path.basename(base)
+
+        dist.metadata.name = name
+
 
 def loader_paths(sourcefn, destfn):
     # Yield (sourcefn, destfn) pairs for all
@@ -107,7 +137,6 @@ def loader_paths(sourcefn, destfn):
 
 
 def rewrite_tkinter_load_commands(tkinter_path):
-    print("rewrite_tk", tkinter_path)
     m = macholib.MachO.MachO(tkinter_path)
     tcl_path = None
     tk_path = None
@@ -280,6 +309,9 @@ def __init__(self, **kw):
         if m and isinstance(m, basestring):
             self.modules = [m]
 
+    def __repr__(self):
+        return "<Target %s>"%(self.__dict__,)
+
     def get_dest_base(self):
         dest_base = getattr(self, "dest_base", None)
         if dest_base:
@@ -1154,6 +1186,7 @@ def process_recipes(self, mf, filters, flatpackages, loader_files):
             else:
                 break
 
+
     def _run(self):
         try:
             if self.alias:
@@ -1533,6 +1566,7 @@ def packagefilter(mod, pkgdirs=pkgdirs):
             if dist_info_path is None and (fn.endswith(".pyc") or fn.endswith(".pyo")):
                 dist_info_path = metadata_infos.get(fn[:-1], None)
             if dist_info_path is not None:
+                print("ADD INFO", dist_info_path)
                 included_metadata.add(dist_info_path)
 
         def files_in_dir(toplevel):
@@ -1592,11 +1626,11 @@ def files_in_dir(toplevel):
                     continue
                 src = os.path.join(pkg_info_path, fn)
                 dst = os.path.join(base, fn)
+
                 if os.path.isdir(src):
                     self.copy_tree(src, dst, preserve_symlinks=False)
                 else:
                     self.copy_file(src, dst)
-
         self.lib_files = []
         self.app_files = []
 

setup.py

@@ -351,6 +351,7 @@ def run(self):
         ],
     },
     entry_points={
+        "setuptools.finalize_distribution_options": ["py2app = py2app.build_app:finalize_distribution_options"],
         "distutils.commands": ["py2app = py2app.build_app:py2app"],
         "distutils.setup_keywords": [
             "app =    py2app.build_app:validate_target",