Merge pull request #105 from hexagonrecursion/fix104

Fix #104 (path pollution)

.gitignore

@@ -4,3 +4,4 @@ __pycache__/
 .tox
 .pytest_cache
 doc/_build/
+*.egg-info/

pep517/in_process/__init__.py

@@ -0,0 +1,17 @@
+"""This is a subpackage because the directory is on sys.path for _in_process.py
+
+The subpackage should stay as empty as possible to avoid shadowing modules that
+the backend might import.
+"""
+from os.path import dirname, abspath, join as pjoin
+from contextlib import contextmanager
+
+try:
+    import importlib.resources as resources
+
+    def _in_proc_script_path():
+        return resources.path(__package__, '_in_process.py')
+except ImportError:
+    @contextmanager
+    def _in_proc_script_path():
+        yield pjoin(dirname(abspath(__file__)), '_in_process.py')

pep517/wrappers.py

@@ -1,13 +1,14 @@
 import threading
 from contextlib import contextmanager
 import os
-from os.path import dirname, abspath, join as pjoin
+from os.path import abspath, join as pjoin
 import shutil
 from subprocess import check_call, check_output, STDOUT
 import sys
 from tempfile import mkdtemp
 
 from . import compat
+from .in_process import _in_proc_script_path
 
 __all__ = [
     'BackendUnavailable',
@@ -19,16 +20,6 @@
     'Pep517HookCaller',
 ]
 
-try:
-    import importlib.resources as resources
-
-    def _in_proc_script_path():
-        return resources.path(__package__, '_in_process.py')
-except ImportError:
-    @contextmanager
-    def _in_proc_script_path():
-        yield pjoin(dirname(abspath(__file__)), '_in_process.py')
-
 
 @contextmanager
 def tempdir():

tests/samples/test-for-issue-104/pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+build-backend = "setuptools.build_meta"

tests/samples/test-for-issue-104/setup.py

@@ -0,0 +1,11 @@
+import sys
+from setuptools import setup
+from os import path, environ, listdir
+import json
+
+children = listdir(sys.path[0])
+out = path.join(environ['PEP517_ISSUE104_OUTDIR'], 'out.json')
+with open(out, 'w') as f:
+    json.dump(children, f)
+
+setup()

tests/test_call_hooks.py

@@ -7,6 +7,7 @@
 import toml
 import zipfile
 import sys
+import json
 
 try:
     from mock import Mock  # Prefer the backport below python 3.6
@@ -154,3 +155,19 @@ def test_custom_python_executable(monkeypatch, tmpdir):
             hooks.get_requires_for_build_wheel()
         runner.assert_called_once()
         assert runner.call_args[0][0][0] == 'some-python'
+
+
+def test_issue_104():
+    hooks = get_hooks('test-for-issue-104')
+    with TemporaryDirectory() as outdir:
+        with modified_env({
+            'PYTHONPATH': BUILDSYS_PKGS,
+            'PEP517_ISSUE104_OUTDIR': outdir,
+        }):
+            hooks.get_requires_for_build_wheel({})
+        with open(pjoin(outdir, 'out.json')) as f:
+            children = json.load(f)
+    assert set(children) <= {
+        '__init__.py', '__init__.pyc', '_in_process.py', '_in_process.pyc',
+        '__pycache__',
+    }