Work around wget bug #784348 which could cause it to clobber git-annex symlinks when downloading from ftp.

Utility/Url.hs

@@ -25,6 +25,9 @@ module Utility.Url (
 ) where
 
 import Common
+import Utility.Tmp
+import qualified Build.SysConfig
+
 import Network.URI
 import Network.HTTP.Conduit
 import Network.HTTP.Types
@@ -32,8 +35,6 @@ import qualified Data.CaseInsensitive as CI
 import qualified Data.ByteString as B
 import qualified Data.ByteString.UTF8 as B8
 
-import qualified Build.SysConfig
-
 type URLString = String
 
 type Headers = [String]
@@ -242,8 +243,15 @@ download' quiet url file uo = do
 		writeFile file ""
 		go "curl" $ headerparams ++ quietopt "-s" ++
 			[Params "-f -L -C - -# -o"]
-	go cmd opts = boolSystem cmd $
-		addUserAgent uo $ reqParams uo++opts++[File file, File url]
+	
+	{- Run wget in a temp directory because it has been buggy
+	 - and overwritten files in the current directory, even though
+	 - it was asked to write to a file elsewhere. -}
+	go cmd opts = withTmpDir "downloadurl" $ \tmp -> do
+		relfile <- relPathDirToFile tmp file
+		let ps = addUserAgent uo $ reqParams uo++opts++[File relfile, File url]
+		boolSystem' cmd ps $ \p -> p { cwd = Just tmp }
+	
 	quietopt s
 		| quiet = [Param s]
 		| otherwise = []

debian/changelog

@@ -27,6 +27,8 @@ git-annex (5.20150421) UNRELEASED; urgency=medium
     the end.
   * assistant: Added --autostop to complement --autostart.
   * Android: Updated bundled ssh from 6.1p1 to 6.4p1.
+  * Work around wget bug #784348 which could cause it to clobber git-annex
+    symlinks when downloading from ftp.
 
  -- Joey Hess <id@joeyh.name>  Tue, 21 Apr 2015 15:54:10 -0400
 

doc/bugs/git-annex_deletes_file_when_using___34__git_annex_get__34___after___34__git_annex_addurl_--file__34__.mdwn

@@ -103,3 +103,5 @@ $
 
 # End of transcript or log.
 """]]
+
+> workaround in place; [[done]] --[[Joey]]

doc/bugs/git-annex_deletes_file_when_using___34__git_annex_get__34___after___34__git_annex_addurl_--file__34__/comment_1_dca81d5db9a966fc992ed28bb3c2a242._comment

@@ -0,0 +1,19 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2015-05-05T17:11:38Z"
+ content="""
+Thanks for a great bug report!
+
+Unfortunately, this turns out to be a bug in wget, as shown by this transcript:
+
+	joey@darkstar:~/tmp/y>ls
+	README@
+	joey@darkstar:~/tmp/y>wget -q --show-progress --clobber -c -O .git/annex/tmp/SHA256E-s1495--8822780b87a880ca9956ac108812557044618859cecb07df488df57e8134e34f ftp://ftp.funet.fi/pub/Linux/mirrors/debian/README --user-agent git-annex/5.20150505-gcdb212f
+	joey@darkstar:~/tmp/y>ls
+	joey@darkstar:~/tmp/y>
+
+I have filed a bug report on wget <http://bugs.debian.org/784348>,
+and I guess I'll try to work around it in git-annex by running wget
+inside an empty temp directory.
+"""]]