Issue #17636: Circular imports involving relative imports are now supported.

11 files changed, 62 insertions, 1 deletions

diff --git a/Lib/test/test_import.py b/Lib/test/test_import/__init__.py
index b4842c5..fd21fa2 100644
--- a/Lib/test/test_import.py
+++ b/Lib/test/test_import/__init__.py
@@ -568,7 +568,7 @@ class RelativeImportTests(unittest.TestCase):
 
     def test_relimport_star(self):
         # This will import * from .test_import.
-        from . import relimport
+        from .. import relimport
         self.assertTrue(hasattr(relimport, "RelativeImportTests"))
 
     def test_issue3221(self):
@@ -1068,6 +1068,46 @@ class ImportTracebackTests(unittest.TestCase):
                                        __isolated=False)
 
 
+class CircularImportTests(unittest.TestCase):
+
+    """See the docstrings of the modules being imported for the purpose of the
+    test."""
+
+    def tearDown(self):
+        """Make sure no modules pre-exist in sys.modules which are being used to
+        test."""
+        for key in list(sys.modules.keys()):
+            if key.startswith('test.test_import.data.circular_imports'):
+                del sys.modules[key]
+
+    def test_direct(self):
+        try:
+            import test.test_import.data.circular_imports.basic
+        except ImportError:
+            self.fail('circular import through relative imports failed')
+
+    def test_indirect(self):
+        try:
+            import test.test_import.data.circular_imports.indirect
+        except ImportError:
+            self.fail('relative import in module contributing to circular '
+                      'import failed')
+
+    def test_subpackage(self):
+        try:
+            import test.test_import.data.circular_imports.subpackage
+        except ImportError:
+            self.fail('circular import involving a subpackage failed')
+
+    def test_rebinding(self):
+        try:
+            import test.test_import.data.circular_imports.rebinding as rebinding
+        except ImportError:
+            self.fail('circular import with rebinding of module attribute failed')
+        from test.test_import.data.circular_imports.subpkg import util
+        self.assertIs(util.util, rebinding.util)
+
+
 if __name__ == '__main__':
     # Test needs to be a package, so we can do relative imports.
     unittest.main()
diff --git a/Lib/test/test_import/__main__.py b/Lib/test/test_import/__main__.py
new file mode 100644
index 0000000..ce26cbd
--- /dev/null
+++ b/Lib/test/test_import/__main__.py
@@ -0,0 +1,3 @@
+import unittest
+
+unittest.main('test.test_import')
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/basic.py b/Lib/test/test_import/data/circular_imports/basic.py
new file mode 100644
index 0000000..3e41e39
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/basic.py
@@ -0,0 +1,2 @@
+"""Circular imports through direct, relative imports."""
+from . import basic2
diff --git a/Lib/test/test_import/data/circular_imports/basic2.py b/Lib/test/test_import/data/circular_imports/basic2.py
new file mode 100644
index 0000000..00bd2f2
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/basic2.py
@@ -0,0 +1 @@
+from . import basic
diff --git a/Lib/test/test_import/data/circular_imports/indirect.py b/Lib/test/test_import/data/circular_imports/indirect.py
new file mode 100644
index 0000000..6925788
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/indirect.py
@@ -0,0 +1 @@
+from . import basic, basic2
diff --git a/Lib/test/test_import/data/circular_imports/rebinding.py b/Lib/test/test_import/data/circular_imports/rebinding.py
new file mode 100644
index 0000000..f51d1c6
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/rebinding.py
@@ -0,0 +1,3 @@
+"""Test the binding of names when a circular import shares the same name as an
+attribute."""
+from .rebinding2 import util
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/rebinding2.py b/Lib/test/test_import/data/circular_imports/rebinding2.py
new file mode 100644
index 0000000..62ca726
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/rebinding2.py
@@ -0,0 +1,3 @@
+from .subpkg import util
+from . import rebinding
+util = util.util
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpackage.py b/Lib/test/test_import/data/circular_imports/subpackage.py
new file mode 100644
index 0000000..cc36c3c
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpackage.py
@@ -0,0 +1,2 @@
+"""Circular import involving a sub-package."""
+from .subpkg import subpackage2
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
new file mode 100644
index 0000000..07e0bc0
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpkg/subpackage2.py
@@ -0,0 +1,2 @@
+#from .util import util
+from .. import subpackage
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/subpkg/util.py b/Lib/test/test_import/data/circular_imports/subpkg/util.py
new file mode 100644
index 0000000..f1505e9
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/subpkg/util.py
@@ -0,0 +1,2 @@
+def util():
+    pass
\ No newline at end of file
diff --git a/Lib/test/test_import/data/circular_imports/util.py b/Lib/test/test_import/data/circular_imports/util.py
new file mode 100644
index 0000000..f1505e9
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/util.py
@@ -0,0 +1,2 @@
+def util():
+    pass
\ No newline at end of file