webdav: Avoid unncessisarily creating the collection at the top of the repo

when storing files there, since that collection is created by initremote.
(This seems to work around some brokenness of the box.com webdav server
which was entering a redirect loop.)

Note that the fix makes locationParent return Nothing instead of "."
when there's no parent directory between the path and the top of the webdav
repo.

This commit was sponsored by André Pereira on Patreon.

CHANGELOG

@@ -2,6 +2,11 @@ git-annex (6.20171004) UNRELEASED; urgency=medium
 
   * webdav: Make --debug show all webdav operations.
   * Fix build with aws-0.17.
+  * webdav: Avoid unncessisarily creating the collection at the top
+    of the repository when storing files there, since that collection
+    is created by initremote.
+    (This seems to work around some brokenness of the box.com webdav
+    server which was entering a redirect loop.)
 
  -- Joey Hess <id@joeyh.name>  Sat, 07 Oct 2017 14:11:00 -0400
 

Remote/WebDAV/DavLocation.hs

@@ -58,10 +58,11 @@ tmpLocation f = "git-annex-webdav-tmp-" ++ f
 
 locationParent :: String -> Maybe String
 locationParent loc
-	| loc `elem` tops = Nothing
+	| loc `elem` tops || parent `elem` tops = Nothing
-	| otherwise = Just (takeDirectory loc)
+	| otherwise = Just parent
   where
 	tops = ["/", "", "."]
+	parent = takeDirectory loc
 
 locationUrl :: URLString -> DavLocation -> URLString
 locationUrl baseurl loc = baseurl </> loc

doc/bugs/Upload_to_box_very_slow.mdwn

@@ -118,3 +118,5 @@ Notice the 5 second gap here:
 ### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)
 
 Yes! Thank you!
+
+> [[fixed|done]] --[[Joey]]