From 92ca04bf10c7bb832039d859f945f43ef8f234fd Mon Sep 17 00:00:00 2001
From: brettlangdon <brett.langdon@datadoghq.com>
Date: Mon, 15 Aug 2022 15:00:45 -0400
Subject: [PATCH] simply example

---
 README.md                             | 23 +++++++++++++++++------
 shadow_import_issue/__init__.py       |  8 ++------
 shadow_import_issue/c_exts/_child.pyx |  5 ++++-
 shadow_import_issue/c_exts/py_mod.py  |  1 -
 shadow_import_issue/sub/child.py      |  5 ++++-
 5 files changed, 27 insertions(+), 15 deletions(-)
 delete mode 100644 shadow_import_issue/c_exts/py_mod.py

diff --git a/README.md b/README.md
index f4c44d4..8b7b480 100644
--- a/README.md
+++ b/README.md
@@ -36,15 +36,26 @@ docker run --rm shadow-import-issue
 Expected output is to fail with:
 
 ```
-pure-python VAR
+<module 'shadow_import_issue.shadow' from '/src/shadow_import_issue/shadow.py'>
+VAR
+<module 'shadow_import_issue.c_exts.shadow_import_issue.shadow' from '/src/shadow_import_issue/c_exts/shadow.py'>
 Traceback (most recent call last):
   File "/src/test.py", line 1, in <module>
     import shadow_import_issue
-  File "/src/shadow_import_issue/__init__.py", line 5, in <module>
-    from .c_exts import _child  # isort:skip
-  File "shadow_import_issue/c_exts/_child.pyx", line 1, in init shadow_import_issue.c_exts._child
-    from shadow_import_issue.shadow import VAR
-ImportError: cannot import name VAR
+  File "/src/shadow_import_issue/__init__.py", line 3, in <module>
+    import shadow_import_issue.c_exts._child  # isort:skip
+  File "shadow_import_issue/c_exts/_child.pyx", line 4, in init shadow_import_issue.c_exts._child
+    print(shadow_import_issue.shadow.VAR)
+AttributeError: module 'shadow_import_issue.c_exts.shadow_import_issue.shadow' has no attribute 'VAR'
 ```
 
 The module and variable will import fine with Python, but will fail the import from the Cython module.
+
+
+## Analysis
+
+- This only happens with editable install
+- This only occurs with `setuptools>=64.0.0`
+   - `setuptools>=64.0.0` changed from using `.egg-link` to `.pth` + editable loader
+- The module loaded by Cython has the name `shadow_import_issue.c_exts.shadow_import_issue.shadow` and is loaded from `shadow_import_issue/c_exts/shadow.py`
+- The issue does not happen with `Cython==3.0.0a11`
diff --git a/shadow_import_issue/__init__.py b/shadow_import_issue/__init__.py
index cd8b01d..892ecc0 100644
--- a/shadow_import_issue/__init__.py
+++ b/shadow_import_issue/__init__.py
@@ -1,7 +1,3 @@
-from .sub import child  # isort:skip
+import shadow_import_issue.sub.child  # isort:skip
 
-print("pure-python", child.VAR)
-
-from .c_exts import _child  # isort:skip
-
-print("cython", _child.VAR)
+import shadow_import_issue.c_exts._child  # isort:skip
diff --git a/shadow_import_issue/c_exts/_child.pyx b/shadow_import_issue/c_exts/_child.pyx
index 2ee6b05..a9b4979 100644
--- a/shadow_import_issue/c_exts/_child.pyx
+++ b/shadow_import_issue/c_exts/_child.pyx
@@ -1 +1,4 @@
-from shadow_import_issue.shadow import VAR
+import shadow_import_issue.shadow
+
+print(shadow_import_issue.shadow)
+print(shadow_import_issue.shadow.VAR)
diff --git a/shadow_import_issue/c_exts/py_mod.py b/shadow_import_issue/c_exts/py_mod.py
deleted file mode 100644
index 7f96e8c..0000000
--- a/shadow_import_issue/c_exts/py_mod.py
+++ /dev/null
@@ -1 +0,0 @@
-# empty on purpose
diff --git a/shadow_import_issue/sub/child.py b/shadow_import_issue/sub/child.py
index 2ee6b05..a9b4979 100644
--- a/shadow_import_issue/sub/child.py
+++ b/shadow_import_issue/sub/child.py
@@ -1 +1,4 @@
-from shadow_import_issue.shadow import VAR
+import shadow_import_issue.shadow
+
+print(shadow_import_issue.shadow)
+print(shadow_import_issue.shadow.VAR)