feat: module shadow (fix jwodder#19)

src/check_wheel_contents/checker.py

@@ -299,6 +299,29 @@ def check_W010(self, contents: WheelContents) -> list[FailedCheck]:
         else:
             return []
 
+    def check_W011(self, contents: WheelContents) -> list[FailedCheck]:
+        """
+        W011 — Conflict between module as a file (.py) and as a folder (__init__.py)
+
+        Checks for both `path/foo.py` and `path/foo/__init__.py` being present
+        """
+        conflicts: list[str] = []
+
+        def check_dir(tree: Directory) -> None:
+            for name, entry in tree.entries.items():
+                if isinstance(entry, Directory):
+                    if tree.files.get(name + ".py") is not None:
+                        conflicts.append(entry.path or name)
+                    check_dir(entry)
+
+        for tree in (contents.purelib_tree, contents.platlib_tree):
+            if isinstance(tree, Directory):
+                check_dir(tree)
+
+        if conflicts:
+            return [FailedCheck(Check.W011, conflicts)]
+        return []
+
     def check_W101(self, contents: WheelContents) -> list[FailedCheck]:
         """
         W101 — Wheel library is missing files in package tree

src/check_wheel_contents/checks.py

@@ -27,6 +27,7 @@ class Check(Enum):
     W102 = "Wheel library contains files not in package tree"
     W201 = "Wheel library is missing specified toplevel entry"
     W202 = "Wheel library has undeclared toplevel entry"
+    W011 = "Wheel library has multiple declared toplevel entries"
 
 
 @attr.s(auto_attribs=True)

test/data/wheels/module_file_folder_shadow-0.1.0-py3-none-any.json

@@ -0,0 +1,5 @@
+{
+    "stdout": "module_file_folder_shadow-0.1.0-py3-none-any.whl: W011: Wheel library has multiple declared toplevel entries:\n  module_file_folder_shadow/foo/\n  module_file_folder_shadow/foo/bar/",
+    "stderr": "",
+    "rc": 1
+}