Merge branch 'ps/reflog-migrate-fixes'

"git refs migrate" to migrate the reflog entries from a refs
backend to another had a handful of bugs squashed.

* ps/reflog-migrate-fixes:
  refs: fix invalid old object IDs when migrating reflogs
  refs: stop unsetting REF_HAVE_OLD for log-only updates
  refs/files: detect race when generating reflog entry for HEAD
  refs: fix identity for migrated reflogs
  ident: fix type of string length parameter
  builtin/reflog: implement subcommand to write new entries
  refs: export `ref_transaction_update_reflog()`
  builtin/reflog: improve grouping of subcommands
  Documentation/git-reflog: convert to use synopsis type

3 files changed, 142 insertions, 7 deletions

diff --git a/t/meson.build b/t/meson.build
index bbeba1a8d5..983245501c 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -204,6 +204,7 @@ integration_tests = [
   't1418-reflog-exists.sh',
   't1419-exclude-refs.sh',
   't1420-lost-found.sh',
+  't1421-reflog-write.sh',
   't1430-bad-ref-name.sh',
   't1450-fsck.sh',
   't1451-fsck-buffer.sh',
diff --git a/t/t1421-reflog-write.sh b/t/t1421-reflog-write.sh
new file mode 100755
index 0000000000..46df64c176
--- /dev/null
+++ b/t/t1421-reflog-write.sh
@@ -0,0 +1,126 @@
+#!/bin/sh
+
+test_description='Manually write reflog entries'
+
+. ./test-lib.sh
+
+SIGNATURE="C O Mitter <committer@example.com> 1112911993 -0700"
+
+test_reflog_matches () {
+	repo="$1" &&
+	refname="$2" &&
+	cat >actual &&
+	test-tool -C "$repo" ref-store main for-each-reflog-ent "$refname" >expected &&
+	test_cmp expected actual
+}
+
+test_expect_success 'invalid number of arguments' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		for args in "" "1" "1 2" "1 2 3" "1 2 3 4 5"
+		do
+			test_must_fail git reflog write $args 2>err &&
+			test_grep "usage: git reflog write" err || return 1
+		done
+	)
+'
+
+test_expect_success 'invalid refname' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_must_fail git reflog write "refs/heads/ invalid" $ZERO_OID $ZERO_OID first 2>err &&
+		test_grep "invalid reference name: " err
+	)
+'
+
+test_expect_success 'unqualified refname is rejected' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_must_fail git reflog write unqualified $ZERO_OID $ZERO_OID first 2>err &&
+		test_grep "invalid reference name: " err
+	)
+'
+
+test_expect_success 'nonexistent object IDs' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_must_fail git reflog write refs/heads/something $(test_oid deadbeef) $ZERO_OID old-object-id 2>err &&
+		test_grep "old object .* does not exist" err &&
+		test_must_fail git reflog write refs/heads/something $ZERO_OID $(test_oid deadbeef) new-object-id 2>err &&
+		test_grep "new object .* does not exist" err
+	)
+'
+
+test_expect_success 'abbreviated object IDs' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		abbreviated_oid=$(git rev-parse HEAD | test_copy_bytes 8) &&
+		test_must_fail git reflog write refs/heads/something $abbreviated_oid $ZERO_OID old-object-id 2>err &&
+		test_grep "invalid old object ID" err &&
+		test_must_fail git reflog write refs/heads/something $ZERO_OID $abbreviated_oid new-object-id 2>err &&
+		test_grep "invalid new object ID" err
+	)
+'
+
+test_expect_success 'reflog message gets normalized' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		COMMIT_OID=$(git rev-parse HEAD) &&
+		git reflog write HEAD $COMMIT_OID $COMMIT_OID "$(printf "message\nwith\nnewlines")" &&
+		git reflog show -1 --format=%gs HEAD >actual &&
+		echo "message with newlines" >expected &&
+		test_cmp expected actual
+	)
+'
+
+test_expect_success 'simple writes' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		COMMIT_OID=$(git rev-parse HEAD) &&
+
+		git reflog write refs/heads/something $ZERO_OID $COMMIT_OID first &&
+		test_reflog_matches . refs/heads/something <<-EOF &&
+		$ZERO_OID $COMMIT_OID $SIGNATURE	first
+		EOF
+
+		git reflog write refs/heads/something $COMMIT_OID $COMMIT_OID second &&
+		test_reflog_matches . refs/heads/something <<-EOF
+		$ZERO_OID $COMMIT_OID $SIGNATURE	first
+		$COMMIT_OID $COMMIT_OID $SIGNATURE	second
+		EOF
+	)
+'
+
+test_expect_success 'can write to root ref' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		COMMIT_OID=$(git rev-parse HEAD) &&
+
+		git reflog write ROOT_REF_HEAD $ZERO_OID $COMMIT_OID first &&
+		test_reflog_matches . ROOT_REF_HEAD <<-EOF
+		$ZERO_OID $COMMIT_OID $SIGNATURE	first
+		EOF
+	)
+'
+
+test_done
diff --git a/t/t1460-refs-migrate.sh b/t/t1460-refs-migrate.sh
index 2ab97e1b7d..0e1116a319 100755
--- a/t/t1460-refs-migrate.sh
+++ b/t/t1460-refs-migrate.sh
@@ -7,6 +7,17 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+print_all_reflog_entries () {
+	repo=$1 &&
+	test-tool -C "$repo" ref-store main for-each-reflog >reflogs &&
+	while read reflog
+	do
+		echo "REFLOG: $reflog" &&
+		test-tool -C "$repo" ref-store main for-each-reflog-ent "$reflog" ||
+		return 1
+	done <reflogs
+}
+
 # Migrate the provided repository from one format to the other and
 # verify that the references and logs are migrated over correctly.
 # Usage: test_migration <repo> <format> [<skip_reflog_verify> [<options...>]]
@@ -28,8 +39,7 @@ test_migration () {
 		--format='%(refname) %(objectname) %(symref)' >expect &&
 	if ! $skip_reflog_verify
 	then
-	   git -C "$repo" reflog --all >expect_logs &&
-	   git -C "$repo" reflog list >expect_log_list
+		print_all_reflog_entries "$repo" >expect_logs
 	fi &&
 
 	git -C "$repo" refs migrate --ref-format="$format" "$@" &&
@@ -39,10 +49,8 @@ test_migration () {
 	test_cmp expect actual &&
 	if ! $skip_reflog_verify
 	then
-		git -C "$repo" reflog --all >actual_logs &&
-		git -C "$repo" reflog list >actual_log_list &&
-		test_cmp expect_logs actual_logs &&
-		test_cmp expect_log_list actual_log_list
+		print_all_reflog_entries "$repo" >actual_logs &&
+		test_cmp expect_logs actual_logs
 	fi &&
 
 	git -C "$repo" rev-parse --show-ref-format >actual &&
@@ -273,7 +281,7 @@ test_expect_success 'multiple reftable blocks with multiple entries' '
 	test_commit -C repo second &&
 	printf "update refs/heads/ref-%d HEAD\n" $(test_seq 3000) >stdin &&
 	git -C repo update-ref --stdin <stdin &&
-	test_migration repo reftable
+	test_migration repo reftable true
 '
 
 test_expect_success 'migrating from files format deletes backend files' '