Issue #17169: Restore errno in tempfile exceptions.

Lib/tempfile.py

@@ -31,6 +31,7 @@ import warnings as _warnings
 import sys as _sys
 import io as _io
 import os as _os
+import errno as _errno
 from random import Random as _Random
 
 try:
@@ -183,7 +184,9 @@ def _get_default_tempdir():
                 pass
             except OSError:
                 break   # no point trying more names in this directory
-    raise FileNotFoundError("No usable temporary directory found in %s" % dirlist)
+    raise FileNotFoundError(_errno.ENOENT,
+                            "No usable temporary directory found in %s" %
+                            dirlist)
 
 _name_sequence = None
 
@@ -216,7 +219,8 @@ def _mkstemp_inner(dir, pre, suf, flags):
         except FileExistsError:
             continue    # try again
 
-    raise FileExistsError("No usable temporary file name found")
+    raise FileExistsError(_errno.EEXIST,
+                          "No usable temporary file name found")
 
 
 # User visible interfaces.
@@ -303,7 +307,8 @@ def mkdtemp(suffix="", prefix=template, dir=None):
         except FileExistsError:
             continue    # try again
 
-    raise FileExistsError("No usable temporary directory name found")
+    raise FileExistsError(_errno.EEXIST,
+                          "No usable temporary directory name found")
 
 def mktemp(suffix="", prefix=template, dir=None):
     """User-callable function to return a unique temporary file name.  The
@@ -332,7 +337,8 @@ def mktemp(suffix="", prefix=template, dir=None):
         if not _exists(file):
             return file
 
-    raise FileExistsError("No usable temporary filename found")
+    raise FileExistsError(_errno.EEXIST,
+                          "No usable temporary filename found")
 
 
 class _TemporaryFileWrapper:

Lib/test/test_tempfile.py

@@ -1,5 +1,6 @@
 # tempfile.py unit tests.
 import tempfile
+import errno
 import os
 import signal
 import sys
@@ -963,8 +964,9 @@ class TestTemporaryDirectory(BaseTestCase):
         # (noted as part of Issue #10188)
         with tempfile.TemporaryDirectory() as nonexistent:
             pass
-        with self.assertRaises(OSError):
+        with self.assertRaises(FileNotFoundError) as cm:
             tempfile.TemporaryDirectory(dir=nonexistent)
+        self.assertEqual(cm.exception.errno, errno.ENOENT)
 
     def test_explicit_cleanup(self):
         # A TemporaryDirectory is deleted when cleaned up