green: keep urllib exceptions identityexc-id-442

https://github.com/eventlet/eventlet/issues/442

General advice - always import modules, not names.

Good: import urllib ; except urllib.URLError
Bad: from urllib import URLError

5 files changed, 61 insertions, 9 deletions

diff --git a/eventlet/green/urllib/__init__.py b/eventlet/green/urllib/__init__.py
index 7cb4ea6..771e5de 100644
--- a/eventlet/green/urllib/__init__.py
+++ b/eventlet/green/urllib/__init__.py
@@ -20,7 +20,6 @@ if six.PY2:
     except NameError:
         patcher.inject('urllib.request', globals(), *to_patch)
 
-
     # patch a bunch of things that have imports inside the
     # function body; this is lame and hacky but I don't feel
     # too bad because urllib is a hacky pile of junk that no
@@ -33,8 +32,8 @@ if six.PY2:
     ftpwrapper.init = patcher.patch_function(ftpwrapper.init, ('ftplib', ftplib))
     ftpwrapper.retrfile = patcher.patch_function(ftpwrapper.retrfile, ('ftplib', ftplib))
 
-    del patcher
+del patcher
 
-    # Run test program when run as a script
-    if __name__ == '__main__':
-        main()
+# Run test program when run as a script
+if __name__ == '__main__':
+    main()
diff --git a/eventlet/green/urllib/error.py b/eventlet/green/urllib/error.py
index 6913813..d074388 100644
--- a/eventlet/green/urllib/error.py
+++ b/eventlet/green/urllib/error.py
@@ -1,4 +1,18 @@
+import sys
 from eventlet import patcher
 from eventlet.green.urllib import response
-patcher.inject('urllib.error', globals(), ('urllib.response', response))
-del patcher
+_canonical_name = 'urllib.error'
+patcher.inject(_canonical_name, globals(), ('urllib.response', response))
+_MISSING = object()
+module_imported = sys.modules.get(_canonical_name, patcher.original(_canonical_name))
+_current_module = sys.modules[__name__]
+_keep_names = (
+    'URLError',
+    'HTTPError',
+    'ContentTooShortError',
+)
+for k in _keep_names:
+    v = getattr(module_imported, k, _MISSING)
+    if v is not _MISSING:
+        setattr(_current_module, k, v)
+del _canonical_name, _current_module, _keep_names, k, v, module_imported, patcher, sys
diff --git a/eventlet/green/urllib2.py b/eventlet/green/urllib2.py
index c53ecbb..d7e3f64 100644
--- a/eventlet/green/urllib2.py
+++ b/eventlet/green/urllib2.py
@@ -1,3 +1,4 @@
+import sys
 from eventlet import patcher
 from eventlet.green import ftplib
 from eventlet.green import httplib
@@ -6,8 +7,9 @@ from eventlet.green import ssl
 from eventlet.green import time
 from eventlet.green import urllib
 
+_canonical_name = 'urllib2'
 patcher.inject(
-    'urllib2',
+    _canonical_name,
     globals(),
     ('httplib', httplib),
     ('socket', socket),
@@ -17,4 +19,15 @@ patcher.inject(
 
 FTPHandler.ftp_open = patcher.patch_function(FTPHandler.ftp_open, ('ftplib', ftplib))
 
-del patcher
+_MISSING = object()
+module_imported = sys.modules.get(_canonical_name, patcher.original(_canonical_name))
+_current_module = sys.modules[__name__]
+_keep_names = (
+    'URLError',
+    'HTTPError',
+)
+for k in _keep_names:
+    v = getattr(module_imported, k, _MISSING)
+    if v is not _MISSING:
+        setattr(_current_module, k, v)
+del _canonical_name, _current_module, _keep_names, k, v, module_imported, patcher, sys
diff --git a/tests/isolated/urllib_exception_identity.py b/tests/isolated/urllib_exception_identity.py
new file mode 100644
index 0000000..6d700b9
--- /dev/null
+++ b/tests/isolated/urllib_exception_identity.py
@@ -0,0 +1,22 @@
+__test__ = False
+
+if __name__ == '__main__':
+    import sys
+    if sys.version_info[0] == 2:
+        import urllib2 as original
+        from eventlet.green import urllib2 as green
+    elif sys.version_info[0] == 3:
+        from urllib import error as original
+        from eventlet.green.urllib import error as green
+    else:
+        raise Exception
+
+    cases = (
+        'URLError',
+        'HTTPError',
+        'ContentTooShortError',
+    )
+    for c in cases:
+        if hasattr(original, c):
+            assert getattr(green, c) is getattr(original, c), c
+    print('pass')
diff --git a/tests/patcher_test.py b/tests/patcher_test.py
index ff59400..bda82b3 100644
--- a/tests/patcher_test.py
+++ b/tests/patcher_test.py
@@ -520,3 +520,7 @@ def test_blocking_select_methods_are_deleted():
 
 def test_regular_file_readall():
     tests.run_isolated('regular_file_readall.py')
+
+
+def test_urllib_exception_identity():
+    tests.run_isolated('urllib_exception_identity.py')