Issue #15343: Handle importlib.machinery.FileFinder instances in pkgutil.walk_packages (et al)

Lib/pkgutil.py

@@ -157,6 +157,49 @@ def iter_importer_modules(importer, prefix=''):
 
 iter_importer_modules = simplegeneric(iter_importer_modules)
 
+# Implement a file walker for the normal importlib path hook
+def _iter_file_finder_modules(importer, prefix=''):
+    if importer.path is None or not os.path.isdir(importer.path):
+        return
+
+    yielded = {}
+    import inspect
+    try:
+        filenames = os.listdir(importer.path)
+    except OSError:
+        # ignore unreadable directories like import does
+        filenames = []
+    filenames.sort()  # handle packages before same-named modules
+
+    for fn in filenames:
+        modname = inspect.getmodulename(fn)
+        if modname=='__init__' or modname in yielded:
+            continue
+
+        path = os.path.join(importer.path, fn)
+        ispkg = False
+
+        if not modname and os.path.isdir(path) and '.' not in fn:
+            modname = fn
+            try:
+                dircontents = os.listdir(path)
+            except OSError:
+                # ignore unreadable directories like import does
+                dircontents = []
+            for fn in dircontents:
+                subname = inspect.getmodulename(fn)
+                if subname=='__init__':
+                    ispkg = True
+                    break
+            else:
+                continue    # not a package
+
+        if modname and '.' not in modname:
+            yielded[modname] = 1
+            yield prefix + modname, ispkg
+
+iter_importer_modules.register(
+    importlib.machinery.FileFinder, _iter_file_finder_modules)
 
 class ImpImporter:
     """PEP 302 Importer that wraps Python's "classic" import algorithm