Fixed #21482 -- Uplifted restriction of collectstatic using symlink option in Windows NT 6.

Original patch by Vajrasky Kok. Reviewed by Florian Apolloner, Aymeric Augustin.

django/contrib/staticfiles/management/commands/collectstatic.py

@@ -1,7 +1,6 @@
 from __future__ import unicode_literals
 
 import os
-import sys
 from collections import OrderedDict
 from optparse import make_option
 
@@ -82,12 +81,8 @@ class Command(NoArgsCommand):
 
         Split off from handle_noargs() to facilitate testing.
         """
-        if self.symlink:
-            if sys.platform == 'win32':
-                raise CommandError("Symlinking is not supported by this "
-                                   "platform (%s)." % sys.platform)
-            if not self.local:
-                raise CommandError("Can't symlink to a remote destination.")
+        if self.symlink and not self.local:
+            raise CommandError("Can't symlink to a remote destination.")
 
         if self.clear:
             self.clear_dir('')
@@ -279,7 +274,18 @@ class Command(NoArgsCommand):
                 os.makedirs(os.path.dirname(full_path))
             except OSError:
                 pass
-            os.symlink(source_path, full_path)
+            try:
+                os.symlink(source_path, full_path)
+            except AttributeError:
+                import platform
+                raise CommandError("Symlinking is not supported by Python %s." %
+                                   platform.python_version())
+            except NotImplementedError:
+                import platform
+                raise CommandError("Symlinking is not supported in this "
+                                   "platform (%s)." % platform.platform())
+            except OSError as e:
+                raise CommandError(e)
         if prefixed_path not in self.symlinked_files:
             self.symlinked_files.append(prefixed_path)
 

django/utils/_os.py

@@ -1,6 +1,7 @@
 import os
 import stat
 import sys
+import tempfile
 from os.path import join, normcase, normpath, abspath, isabs, sep, dirname
 
 from django.utils.encoding import force_text
@@ -99,3 +100,24 @@ def rmtree_errorhandler(func, path, exc_info):
     os.chmod(path, stat.S_IWRITE)
     # use the original function to repeat the operation
     func(path)
+
+
+def symlinks_supported():
+    """
+    A function to check if creating symlinks are supported in the
+    host platform and/or if they are allowed to be created (e.g.
+    on Windows it requires admin permissions).
+    """
+    tmpdir = tempfile.mkdtemp()
+    original_path = os.path.join(tmpdir, 'original')
+    symlink_path = os.path.join(tmpdir, 'symlink')
+    os.makedirs(original_path)
+    try:
+        os.symlink(original_path, symlink_path)
+        supported = True
+    except (OSError, NotImplementedError, AttributeError):
+        supported = False
+    else:
+        os.remove(symlink_path)
+    finally:
+        return supported