From 06dca68b73ccbc385f2ca99ec0606c38bf805415 Mon Sep 17 00:00:00 2001
From: Neil Mitchell <ndmitchell@gmail.com>
Date: Wed, 30 Dec 2015 16:33:09 +0000
Subject: [PATCH 1/2] #1418, if git fetch fails wipe the directory and try
 again from scratch

---
 src/Stack/PackageIndex.hs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/Stack/PackageIndex.hs b/src/Stack/PackageIndex.hs
index 92fcfdfb4e..6fe4b7e2d7 100644
--- a/src/Stack/PackageIndex.hs
+++ b/src/Stack/PackageIndex.hs
@@ -13,6 +13,7 @@
 {-# LANGUAGE TemplateHaskell            #-}
 {-# LANGUAGE TupleSections              #-}
 {-# LANGUAGE ViewPatterns               #-}
+{-# LANGUAGE ScopedTypeVariables        #-}
 
 -- | Dealing with the 00-index file and all its cabal files.
 module Stack.PackageIndex
@@ -64,7 +65,8 @@ import           Stack.Types.StackT
 import           System.FilePath (takeBaseName, (<.>))
 import           System.IO                             (IOMode (ReadMode, WriteMode),
                                                         withBinaryFile)
-import           System.Process.Read (readInNull, EnvOverride, doesExecutableExist)
+import           System.Process.Read (readInNull, readProcessNull, ReadProcessException(..),
+                                      EnvOverride, doesExecutableExist)
 
 -- | Populate the package index caches and return them.
 populateCache
@@ -243,7 +245,13 @@ updateIndexGit menv indexName' index gitUrl = do
             unless repoExists
                    (readInNull suDir "git" menv cloneArgs Nothing)
             $logSticky "Fetching package index ..."
-            readInNull acfDir "git" menv ["fetch","--tags","--depth=1"] Nothing
+            readProcessNull (Just acfDir) menv "git" ["fetch","--tags","--depth=1"] `C.catch` \(_ :: ReadProcessException) -> do
+              -- we failed, so wipe the directory and try again, see #1418
+              $logStickyDone "Failed to fetch package index, retrying."
+              removeTree acfDir
+              readInNull suDir "git" menv cloneArgs Nothing
+              $logSticky "Fetching package index ..."
+              readInNull acfDir "git" menv ["fetch","--tags","--depth=1"] Nothing
             $logStickyDone "Fetched package index."
             removeFileIfExists tarFile
             when (indexGpgVerify index)

From 71fa0568363f7566f6ad088c450d4cac3fa1b57b Mon Sep 17 00:00:00 2001
From: Neil Mitchell <ndmitchell@gmail.com>
Date: Thu, 31 Dec 2015 18:31:51 +0000
Subject: [PATCH 2/2] Also log the error message when git updating fails

---
 src/Stack/PackageIndex.hs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Stack/PackageIndex.hs b/src/Stack/PackageIndex.hs
index 6fe4b7e2d7..2b7075a793 100644
--- a/src/Stack/PackageIndex.hs
+++ b/src/Stack/PackageIndex.hs
@@ -245,8 +245,9 @@ updateIndexGit menv indexName' index gitUrl = do
             unless repoExists
                    (readInNull suDir "git" menv cloneArgs Nothing)
             $logSticky "Fetching package index ..."
-            readProcessNull (Just acfDir) menv "git" ["fetch","--tags","--depth=1"] `C.catch` \(_ :: ReadProcessException) -> do
+            readProcessNull (Just acfDir) menv "git" ["fetch","--tags","--depth=1"] `C.catch` \(ex :: ReadProcessException) -> do
               -- we failed, so wipe the directory and try again, see #1418
+              $logWarn (T.pack (show ex))
               $logStickyDone "Failed to fetch package index, retrying."
               removeTree acfDir
               readInNull suDir "git" menv cloneArgs Nothing