Merge pull request git-lfs#3383 from bk2204/shared-repo-hang

Avoid hang in repos cloned with --shared or --reference

Author: bk2204

commands/command_status.go

@@ -34,8 +34,6 @@ func statusCommand(cmd *cobra.Command, args []string) {
 
 	scanner, err := lfs.NewPointerScanner()
 	if err != nil {
-		scanner.Close()
-
 		ExitWithError(err)
 	}
 

go.mod

@@ -3,7 +3,7 @@ module github.com/git-lfs/git-lfs
 require (
 	github.com/ThomsonReutersEikon/go-ntlm v0.0.0-20151030004737-b00ec39bbdd0
 	github.com/alexbrainman/sspi v0.0.0-20180125232955-4729b3d4d858
-	github.com/git-lfs/gitobj v1.0.0
+	github.com/git-lfs/gitobj v1.1.0
 	github.com/git-lfs/go-netrc v0.0.0-20180525200031-e0e9ca483a18
 	github.com/git-lfs/wildmatch v1.0.0
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect

go.sum

@@ -4,8 +4,8 @@ github.com/alexbrainman/sspi v0.0.0-20180125232955-4729b3d4d858 h1:OZQyEhf4Bviyd
 github.com/alexbrainman/sspi v0.0.0-20180125232955-4729b3d4d858/go.mod h1:976q2ETgjT2snVCf2ZaBnyBbVoPERGjUz+0sofzEfro=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/git-lfs/gitobj v1.0.0 h1:+tZj++WOWMNTMP3aMJrKel8ogWkN+hRRCGNVUE+UXio=
-github.com/git-lfs/gitobj v1.0.0/go.mod h1:EdPNGHVxXe1jTuNXzZT1+CdJCuASoDSLPQuvNOo9nGM=
+github.com/git-lfs/gitobj v1.1.0 h1:XRUyk5nKYTWiO8U4cokO5QeoNUNBL8LKS+jXxXZdCTA=
+github.com/git-lfs/gitobj v1.1.0/go.mod h1:EdPNGHVxXe1jTuNXzZT1+CdJCuASoDSLPQuvNOo9nGM=
 github.com/git-lfs/go-netrc v0.0.0-20180525200031-e0e9ca483a18 h1:7Th0eBA4rT8WJNiM1vppjaIv9W5WJinhpbCJvRJxloI=
 github.com/git-lfs/go-netrc v0.0.0-20180525200031-e0e9ca483a18/go.mod h1:70O4NAtvWn1jW8V8V+OKrJJYcxDLTmIozfi2fmSz5SI=
 github.com/git-lfs/wildmatch v1.0.0 h1:TKsxqSrEXWj73N4xGcN/ISal8/JJOiAcOv9LH6Zprxw=

lfs/gitscanner_tree.go

@@ -49,17 +49,17 @@ func runScanTree(cb GitScannerFoundPointer, ref string, filter *filepathfilter.F
 func catFileBatchTree(treeblobs *TreeBlobChannelWrapper) (*PointerChannelWrapper, error) {
 	scanner, err := NewPointerScanner()
 	if err != nil {
-		scanner.Close()
-
 		return nil, err
 	}
 
 	pointers := make(chan *WrappedPointer, chanBufSize)
 	errchan := make(chan error, 10) // Multiple errors possible
 
 	go func() {
+		hasNext := true
 		for t := range treeblobs.Results {
-			hasNext := scanner.Scan(t.Sha1)
+			hasNext = scanner.Scan(t.Sha1)
+
 			if p := scanner.Pointer(); p != nil {
 				p.Name = t.Filename
 				pointers <- p
@@ -74,10 +74,14 @@ func catFileBatchTree(treeblobs *TreeBlobChannelWrapper) (*PointerChannelWrapper
 			}
 		}
 
-		// Deal with nested error from incoming treeblobs
-		err := treeblobs.Wait()
-		if err != nil {
-			errchan <- err
+		// If the scanner quit early, we may still have treeblobs to
+		// read, so waiting for it to close will cause a deadlock.
+		if hasNext {
+			// Deal with nested error from incoming treeblobs
+			err := treeblobs.Wait()
+			if err != nil {
+				errchan <- err
+			}
 		}
 
 		if err = scanner.Close(); err != nil {

t/t-fetch.sh

@@ -51,8 +51,9 @@ begin_test "init for fetch tests"
   git push origin newbranch
   assert_server_object "$reponame" "$b_oid"
 
-  # This clone is used for subsequent tests
+  # These clones are used for subsequent tests
   clone_repo "$reponame" clone
+  git clone --shared "$TRASHDIR/clone" "$TRASHDIR/shared"
 )
 end_test
 
@@ -70,6 +71,21 @@ begin_test "fetch"
 )
 end_test
 
+begin_test "fetch (shared repository)"
+(
+  set -e
+  cd shared
+  rm -rf .git/lfs/objects
+
+  git lfs fetch 2>&1 | tee fetch.log
+  ! grep "Could not scan" fetch.log
+  assert_local_object "$contents_oid" 1
+
+  git lfs fsck 2>&1 | tee fsck.log
+  grep "Git LFS fsck OK" fsck.log
+)
+end_test
+
 begin_test "fetch with remote"
 (
   set -e

vendor/github.com/git-lfs/gitobj/backend.go

@@ -6,7 +6,7 @@ github.com/alexbrainman/sspi
 github.com/alexbrainman/sspi/ntlm
 # github.com/davecgh/go-spew v1.1.1
 github.com/davecgh/go-spew/spew
-# github.com/git-lfs/gitobj v1.0.0
+# github.com/git-lfs/gitobj v1.1.0
 github.com/git-lfs/gitobj
 github.com/git-lfs/gitobj/errors
 github.com/git-lfs/gitobj/pack