notes: implement helpers needed for note copying during rewrite

Implement helper functions to load the rewriting config, and to
actually copy the notes.  Also document the config.

Secondly, also implement an undocumented --for-rewrite=<cmd> option to
'git notes copy' which is used like --stdin, but also puts the
configuration for <cmd> into effect.  It will be needed to support the
copying in git-rebase.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 197 insertions, 0 deletions

diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
index 60ad6a1675..aeec90a8e9 100755
--- a/t/t3301-notes.sh
+++ b/t/t3301-notes.sh
@@ -810,4 +810,199 @@ test_expect_success 'git notes copy --stdin' '
 	test "$(git notes list HEAD^)" = "$(git notes list HEAD~3)"
 '
 
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+commit be28d8b4d9951ad940d229ee3b0b9ee3b1ec273d
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:26:13 2005 -0700
+
+    14th
+EOF
+
+test_expect_success 'git notes copy --for-rewrite (unconfigured)' '
+	test_commit 14th &&
+	test_commit 15th &&
+	(echo $(git rev-parse HEAD~3) $(git rev-parse HEAD^); \
+	echo $(git rev-parse HEAD~2) $(git rev-parse HEAD)) |
+	git notes copy --for-rewrite=foo &&
+	git log -2 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    yet another note
+$whitespace
+    yet another note
+
+commit be28d8b4d9951ad940d229ee3b0b9ee3b1ec273d
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:26:13 2005 -0700
+
+    14th
+
+Notes (other):
+    other note
+$whitespace
+    yet another note
+EOF
+
+test_expect_success 'git notes copy --for-rewrite (enabled)' '
+	git config notes.rewriteMode overwrite &&
+	git config notes.rewriteRef "refs/notes/*" &&
+	(echo $(git rev-parse HEAD~3) $(git rev-parse HEAD^); \
+	echo $(git rev-parse HEAD~2) $(git rev-parse HEAD)) |
+	git notes copy --for-rewrite=foo &&
+	git log -2 > output &&
+	test_cmp expect output
+'
+
+test_expect_success 'git notes copy --for-rewrite (disabled)' '
+	git config notes.rewrite.bar false &&
+	echo $(git rev-parse HEAD~3) $(git rev-parse HEAD) |
+	git notes copy --for-rewrite=bar &&
+	git log -2 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    a fresh note
+EOF
+
+test_expect_success 'git notes copy --for-rewrite (overwrite)' '
+	git notes add -f -m"a fresh note" HEAD^ &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+test_expect_success 'git notes copy --for-rewrite (ignore)' '
+	git config notes.rewriteMode ignore &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    a fresh note
+    another fresh note
+EOF
+
+test_expect_success 'git notes copy --for-rewrite (append)' '
+	git notes add -f -m"another fresh note" HEAD^ &&
+	git config notes.rewriteMode concatenate &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    a fresh note
+    another fresh note
+    append 1
+    append 2
+EOF
+
+test_expect_success 'git notes copy --for-rewrite (append two to one)' '
+	git notes add -f -m"append 1" HEAD^ &&
+	git notes add -f -m"append 2" HEAD^^ &&
+	(echo $(git rev-parse HEAD^) $(git rev-parse HEAD);
+	echo $(git rev-parse HEAD^^) $(git rev-parse HEAD)) |
+	git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+test_expect_success 'git notes copy --for-rewrite (append empty)' '
+	git notes remove HEAD^ &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    replacement note 1
+EOF
+
+test_expect_success 'GIT_NOTES_REWRITE_MODE works' '
+	git notes add -f -m"replacement note 1" HEAD^ &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	GIT_NOTES_REWRITE_MODE=overwrite git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+cat > expect << EOF
+commit 37a0d4cba38afef96ba54a3ea567e6dac575700b
+Author: A U Thor <author@example.com>
+Date:   Thu Apr 7 15:27:13 2005 -0700
+
+    15th
+
+Notes (other):
+    replacement note 2
+EOF
+
+test_expect_success 'GIT_NOTES_REWRITE_REF works' '
+	git config notes.rewriteMode overwrite &&
+	git notes add -f -m"replacement note 2" HEAD^ &&
+	git config --unset-all notes.rewriteRef &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	GIT_NOTES_REWRITE_REF=refs/notes/commits:refs/notes/other \
+		git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
+
+test_expect_success 'GIT_NOTES_REWRITE_REF overrides config' '
+	git config notes.rewriteRef refs/notes/other &&
+	git notes add -f -m"replacement note 3" HEAD^ &&
+	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
+	GIT_NOTES_REWRITE_REF= git notes copy --for-rewrite=foo &&
+	git log -1 > output &&
+	test_cmp expect output
+'
 test_done
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 90115863bc..806b83292f 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -56,6 +56,8 @@ unset SHA1_FILE_DIRECTORIES
 unset SHA1_FILE_DIRECTORY
 unset GIT_NOTES_REF
 unset GIT_NOTES_DISPLAY_REF
+unset GIT_NOTES_REWRITE_REF
+unset GIT_NOTES_REWRITE_MODE
 GIT_MERGE_VERBOSITY=5
 export GIT_MERGE_VERBOSITY
 export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME