[Python-checkins] bpo-38811: Check for presence of os.link method in pathlib (GH-17225)

Mon Dec 16 07:24:00 EST 2019

https://github.com/python/cpython/commit/092435e932dee1802784ec28f39454f50fdd879a
commit: 092435e932dee1802784ec28f39454f50fdd879a
branch: master
author: Toke Høiland-Jørgensen <toke at redhat.com>
committer: Victor Stinner <vstinner at python.org>
date: 2019年12月16日T13:23:55+01:00
summary:
bpo-38811: Check for presence of os.link method in pathlib (GH-17225)
Commit 6b5b013bcc22 ("bpo-26978: Implement pathlib.Path.link_to (Using
os.link) (GH-12990)") introduced a new link_to method in pathlib. However,
this makes pathlib crash when the 'os' module is missing a 'link' method.
Fix this by checking for the presence of the 'link' method on pathlib
module import, and if it's not present, turn it into a runtime error like
those emitted when there is no lchmod() or symlink().
Signed-off-by: Toke Høiland-Jørgensen <toke at redhat.com>
files:
A Misc/NEWS.d/next/Library/2019-11-15-18-06-04.bpo-38811.AmdQ6M.rst
M Lib/pathlib.py
M Lib/test/test_pathlib.py

diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index f0537cfea19ab..7d1d1150b0da8 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -418,7 +418,12 @@ def lchmod(self, pathobj, mode):
 
 unlink = os.unlink
 
- link_to = os.link
+ if hasattr(os, "link"):
+ link_to = os.link
+ else:
+ @staticmethod
+ def link_to(self, target):
+ raise NotImplementedError("os.link() not available on this system")
 
 rmdir = os.rmdir
 
diff --git a/Lib/test/test_pathlib.py b/Lib/test/test_pathlib.py
index b8e7fcc2e3029..3232649f55477 100644
--- a/Lib/test/test_pathlib.py
+++ b/Lib/test/test_pathlib.py
@@ -1759,6 +1759,7 @@ def test_rmdir(self):
 self.assertFileNotFound(p.stat)
 self.assertFileNotFound(p.unlink)
 
+ @unittest.skipUnless(hasattr(os, "link"), "os.link() is not present")
 def test_link_to(self):
 P = self.cls(BASE)
 p = P / 'fileA'
@@ -1778,6 +1779,15 @@ def test_link_to(self):
 self.assertEqual(os.stat(r).st_size, size)
 self.assertTrue(q.stat)
 
+ @unittest.skipIf(hasattr(os, "link"), "os.link() is present")
+ def test_link_to_not_implemented(self):
+ P = self.cls(BASE)
+ p = P / 'fileA'
+ # linking to another path.
+ q = P / 'dirA' / 'fileAA'
+ with self.assertRaises(NotImplementedError):
+ p.link_to(q)
+
 def test_rename(self):
 P = self.cls(BASE)
 p = P / 'fileA'
diff --git a/Misc/NEWS.d/next/Library/2019-11-15-18-06-04.bpo-38811.AmdQ6M.rst b/Misc/NEWS.d/next/Library/2019-11-15-18-06-04.bpo-38811.AmdQ6M.rst
new file mode 100644
index 0000000000000..0e4a7f5bdf538
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-11-15-18-06-04.bpo-38811.AmdQ6M.rst
@@ -0,0 +1 @@
+Fix an unhandled exception in :mod:`pathlib` when :meth:`os.link` is missing. Patch by Toke Høiland-Jørgensen.
