Support gitlinks in fast-import.

Currently fast-import/export cannot be used for
repositories with submodules. This patch extends
the relevant programs to make them correctly
process gitlinks.

Links can be represented by two forms of the
Modify command:

M 160000 SHA1 some/path

which sets the link target explicitly, or

M 160000 :mark some/path

where the mark refers to a commit. The latter
form can be used by importing tools to build
all submodules simultaneously in one physical
repository, and then simply fetch them apart.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 194 insertions, 0 deletions

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index e17afa8c3..1fc06c5a2 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -918,4 +918,156 @@ test_expect_success \
 	 grep "progress " <input >expect &&
 	 test_cmp expect actual'
 
+###
+### series P (gitlinks)
+###
+
+cat >input <<INPUT_END
+blob
+mark :1
+data 10
+test file
+
+reset refs/heads/sub
+commit refs/heads/sub
+mark :2
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 12
+sub_initial
+M 100644 :1 file
+
+blob
+mark :3
+data <<DATAEND
+[submodule "sub"]
+	path = sub
+	url = "`pwd`/sub"
+DATAEND
+
+commit refs/heads/subuse1
+mark :4
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 8
+initial
+from refs/heads/master
+M 100644 :3 .gitmodules
+M 160000 :2 sub
+
+blob
+mark :5
+data 20
+test file
+more data
+
+commit refs/heads/sub
+mark :6
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 11
+sub_second
+from :2
+M 100644 :5 file
+
+commit refs/heads/subuse1
+mark :7
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 7
+second
+from :4
+M 160000 :6 sub
+
+INPUT_END
+
+test_expect_success \
+	'P: supermodule & submodule mix' \
+	'git-fast-import <input &&
+	 git checkout subuse1 &&
+	 rm -rf sub && mkdir sub && cd sub &&
+	 git init &&
+	 git fetch .. refs/heads/sub:refs/heads/master &&
+	 git checkout master &&
+	 cd .. &&
+	 git submodule init &&
+	 git submodule update'
+
+SUBLAST=$(git-rev-parse --verify sub)
+SUBPREV=$(git-rev-parse --verify sub^)
+
+cat >input <<INPUT_END
+blob
+mark :1
+data <<DATAEND
+[submodule "sub"]
+	path = sub
+	url = "`pwd`/sub"
+DATAEND
+
+commit refs/heads/subuse2
+mark :2
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 8
+initial
+from refs/heads/master
+M 100644 :1 .gitmodules
+M 160000 $SUBPREV sub
+
+commit refs/heads/subuse2
+mark :3
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data 7
+second
+from :2
+M 160000 $SUBLAST sub
+
+INPUT_END
+
+test_expect_success \
+	'P: verbatim SHA gitlinks' \
+	'git branch -D sub &&
+	 git gc && git prune &&
+	 git-fast-import <input &&
+	 test $(git-rev-parse --verify subuse2) = $(git-rev-parse --verify subuse1)'
+
+test_tick
+cat >input <<INPUT_END
+commit refs/heads/subuse3
+mark :1
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+corrupt
+COMMIT
+
+from refs/heads/subuse2
+M 160000 inline sub
+data <<DATA
+$SUBPREV
+DATA
+
+INPUT_END
+
+test_expect_success 'P: fail on inline gitlink' '
+    ! git-fast-import <input'
+
+test_tick
+cat >input <<INPUT_END
+blob
+mark :1
+data <<DATA
+$SUBPREV
+DATA
+
+commit refs/heads/subuse3
+mark :2
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+corrupt
+COMMIT
+
+from refs/heads/subuse2
+M 160000 :1 sub
+
+INPUT_END
+
+test_expect_success 'P: fail on blob mark in gitlink' '
+    ! git-fast-import <input'
+
 test_done
diff --git a/t/t9301-fast-export.sh b/t/t9301-fast-export.sh
index 0959f2f81..8324f6e3b 100755
--- a/t/t9301-fast-export.sh
+++ b/t/t9301-fast-export.sh
@@ -143,4 +143,46 @@ test_expect_success 'signed-tags=strip' '
 
 '
 
+test_expect_success 'setup submodule' '
+
+	git checkout -f master &&
+	mkdir sub &&
+	cd sub &&
+	git init  &&
+	echo test file > file &&
+	git add file &&
+	git commit -m sub_initial &&
+	cd .. &&
+	git submodule add "`pwd`/sub" sub &&
+	git commit -m initial &&
+	test_tick &&
+	cd sub &&
+	echo more data >> file &&
+	git add file &&
+	git commit -m sub_second &&
+	cd .. &&
+	git add sub &&
+	git commit -m second
+
+'
+
+test_expect_success 'submodule fast-export | fast-import' '
+
+	SUBENT1=$(git ls-tree master^ sub) &&
+	SUBENT2=$(git ls-tree master sub) &&
+	rm -rf new &&
+	mkdir new &&
+	git --git-dir=new/.git init &&
+	git fast-export --signed-tags=strip --all |
+	(cd new &&
+	 git fast-import &&
+	 test "$SUBENT1" = "$(git ls-tree refs/heads/master^ sub)" &&
+	 test "$SUBENT2" = "$(git ls-tree refs/heads/master sub)" &&
+	 git checkout master &&
+	 git submodule init &&
+	 git submodule update &&
+	 cmp sub/file ../sub/file)
+
+'
+
 test_done