Also include package dist-info for editable installs

For editable installs the .egg-info/.dist-info does not
contain a list of installed files. Calculate the list of
files to include from the toplevels in the distribution.

Fixes #417

doc/changelog.rst

@@ -4,6 +4,8 @@ Release history
 py2app 0.28
 -----------
 
+* #417: Also include package dist-info for editable installs
+
 * The qt5 and qt6 recipes used dodge logic to detect
   if the Qt library itself is inside the python package,
   resulting in duplicate copies of Qt.

py2app/_pkg_meta.py

@@ -3,7 +3,7 @@
 IGNORED_DISTINFO = set(["installed-files.txt", "RECORD"])  # noqa: C405
 
 
-def update_metadata_cache(infos, dist_info_path):
+def update_metadata_cache_distinfo(infos, dist_info_path):
     """
     Update mapping from filename to dist_info directory
     for all files installed by the package described
@@ -40,6 +40,56 @@ def update_metadata_cache(infos, dist_info_path):
                     )
                 ] = dist_info_path
 
+def update_metadata_cache_distlink(infos, dist_link_path):
+    """
+    Update mapping from filename to dist_info directory
+    for all files in the package installed in editable mode.
+
+    *dist_link_path* is the .egg-link file for the package
+    """
+    # An editable install does not contain a listing of installed
+    # files.
+    with open(dist_link_path, "r") as fp:
+        dn = fp.readline()[:-1]
+
+
+    # The list of files and directories that would have been
+    # in the list of installed items.
+    to_include = []
+
+    # First look for the dist-info for this editable install
+    for fn in os.listdir(dn):
+        if fn.endswith(".egg-info") or fn.endswith(".dist-info"):
+            dist_info_path = os.path.join(dn, fn)
+            to_include.append(dist_info_path)
+            try:
+                with open(os.path.join(dist_info_path, "top_level.txt"), "r") as fp:
+                    toplevels = fp.read().splitlines()
+            except OSError:
+                continue
+            break
+    else:
+        # No dist-info for this install
+        return
+
+    # Then look for the toplevels for this package
+    for fn in os.listdir(dn):
+        if fn in toplevels or fn.rstrip(".py") in toplevels:
+            to_include.append(os.path.join(dn, fn))
+
+    # Finally recursively add all items found to
+    # the cache.
+    add_recursive(infos, dist_info_path, to_include)
+
+def add_recursive(infos, dist_info_path, to_include):
+    """ Add items from to_include to infos, recursively 
+        walking into directories """
+    for item in to_include:
+        if os.path.isdir(item):
+            add_recursive(infos, dist_info_path, [os.path.join(item, fn) for fn in os.listdir(item)])
+
+        else:
+            infos[item] = dist_info_path
 
 def scan_for_metadata(path):
     """
@@ -52,7 +102,13 @@ def scan_for_metadata(path):
         if not os.path.isdir(dirname):
             continue
         for nm in os.listdir(dirname):
-            if nm.endswith(".egg-info") or nm.endswith(".dist-info"):
-                update_metadata_cache(infos, os.path.join(dirname, nm))
+            if nm.endswith(".egg-link"):
+                # Editable install, these will be found later on in 
+                # *path* as well, but contain metadata without a list
+                # of installed files.
+                update_metadata_cache_distlink(infos, os.path.join(dirname, nm))
+
+            elif nm.endswith(".egg-info") or nm.endswith(".dist-info"):
+                update_metadata_cache_distinfo(infos, os.path.join(dirname, nm))
 
     return infos