commit - 8c25a0e66cb5f6ea96b120f8e80703e83a6ce85e
commit + 02a9e99535e18f69e38c094b381dbd90621a2783
blob - 4e9891df54e61ef79c78c24c78c772e6664da73a
blob + 145bd98f76a62eda56e68cde432493c01e1f315d
--- got/got.c
+++ got/got.c
@@ -9663,8 +9663,11 @@ cmd_commit(int argc, char *argv[])
 	if (error)
 		goto done;
 
-	if (author == NULL)
+	if (author == NULL) {
+		/* got_worktree_commit() treats committer as the optional one */
 		author = committer;
+		committer = NULL;	/* => author timestamp is ignored */
+	}
 
 	if (logmsg == NULL || strlen(logmsg) == 0) {
 		error = get_editor(&editor);
@@ -9714,8 +9717,8 @@ cmd_commit(int argc, char *argv[])
 		cl_arg.branch_name += 11;
 	}
 	cl_arg.repo_path = got_repo_get_path(repo);
-	error = got_worktree_commit(&id, worktree, &paths, author, committer,
-	    allow_bad_symlinks, show_diff, commit_conflicts,
+	error = got_worktree_commit(&id, worktree, &paths, author, time(NULL),
+	    committer, allow_bad_symlinks, show_diff, commit_conflicts,
 	    collect_commit_logmsg, &cl_arg, print_status, NULL, repo);
 	if (error) {
 		if (error->code != GOT_ERR_COMMIT_MSG_EMPTY &&
@@ -13960,7 +13963,7 @@ cmd_merge(int argc, char *argv[])
 		goto done;
 	} else {
 		error = got_worktree_merge_commit(&merge_commit_id, worktree,
-		    fileindex, author, NULL, 1, branch_tip, branch_name,
+		    fileindex, author, 0, NULL, 1, branch_tip, branch_name,
 		    allow_conflict, repo, continue_merge ? print_status : NULL,
 		    NULL);
 		if (error)
blob - 83894a63327d718f09bcb4236d42ccb4c872da6b
blob + 02eac9d035f16856319eb37dc346588302cb7a2e
--- include/got_worktree.h
+++ include/got_worktree.h
@@ -280,12 +280,14 @@ typedef const struct got_error *(*got_worktree_commit_
  * current base commit.
  * An author and a non-empty log message must be specified.
  * The name of the committer is optional (may be NULL).
+ * If a committer is given, a separate author timestamp can be specified
+ * which is ignored otherwise.
  * If a path to be committed contains a symlink which points outside
  * of the path space under version control, raise an error unless
  * committing of such paths is being forced by the caller.
  */
 const struct got_error *got_worktree_commit(struct got_object_id **,
-    struct got_worktree *, struct got_pathlist_head *, const char *,
+    struct got_worktree *, struct got_pathlist_head *, const char *, time_t,
     const char *, int, int, int, got_worktree_commit_msg_cb, void *,
     got_worktree_status_cb, void *, struct got_repository *);
 
@@ -503,9 +505,9 @@ got_worktree_merge_branch(struct got_worktree *worktre
 const struct got_error *
 got_worktree_merge_commit(struct got_object_id **new_commit_id,
     struct got_worktree *worktree, struct got_fileindex *fileindex,
-    const char *author, const char *committer, int allow_bad_symlinks,
-    struct got_object_id *branch_tip, const char *branch_name,
-    int allow_conflict, struct got_repository *repo,
+    const char *author, time_t author_time, const char *committer,
+    int allow_bad_symlinks, struct got_object_id *branch_tip,
+    const char *branch_name, int allow_conflict, struct got_repository *repo,
     got_worktree_status_cb status_cb, void *status_arg);
 
 /*
blob - d089bc9ca0d1abc94a4a52d9c1aaa70f7b02ef28
blob + ec38218e360c5bf4089f0760557e463daffa3a38
--- lib/worktree.c
+++ lib/worktree.c
@@ -6470,8 +6470,8 @@ commit_worktree(struct got_object_id **new_commit_id,
     struct got_object_id *head_commit_id,
     struct got_object_id *parent_id2,
     struct got_worktree *worktree,
-    const char *author, const char *committer, char *diff_path,
-    got_worktree_commit_msg_cb commit_msg_cb, void *commit_arg,
+    const char *author, time_t author_time, const char *committer,
+    char *diff_path, got_worktree_commit_msg_cb commit_msg_cb, void *commit_arg,
     got_worktree_status_cb status_cb, void *status_arg,
     struct got_repository *repo)
 {
@@ -6559,8 +6559,10 @@ commit_worktree(struct got_object_id **new_commit_id,
 		nparents++;
 	}
 	timestamp = time(NULL);
+	if (committer == NULL)
+		author_time = timestamp;
 	err = got_object_commit_create(new_commit_id, new_tree_id, &parent_ids,
-	    nparents, author, timestamp, committer, timestamp, logmsg, repo);
+	    nparents, author, author_time, committer, timestamp, logmsg, repo);
 	if (logmsg != NULL)
 		free(logmsg);
 	if (err)
@@ -6676,8 +6678,8 @@ check_non_staged_files(struct got_fileindex *fileindex
 const struct got_error *
 got_worktree_commit(struct got_object_id **new_commit_id,
     struct got_worktree *worktree, struct got_pathlist_head *paths,
-    const char *author, const char *committer, int allow_bad_symlinks,
-    int show_diff, int commit_conflicts,
+    const char *author, time_t author_time, const char *committer,
+    int allow_bad_symlinks, int show_diff, int commit_conflicts,
     got_worktree_commit_msg_cb commit_msg_cb, void *commit_arg,
     got_worktree_status_cb status_cb, void *status_arg,
     struct got_repository *repo)
@@ -6790,7 +6792,7 @@ got_worktree_commit(struct got_object_id **new_commit_
 	}
 
 	err = commit_worktree(new_commit_id, &commitable_paths,
-	    head_commit_id, NULL, worktree, author, committer,
+	    head_commit_id, NULL, worktree, author, author_time, committer,
 	    (diff_path && cc_arg.diff_header_shown) ? diff_path : NULL,
 	    commit_msg_cb, commit_arg, status_cb, status_arg, repo);
 	if (err)
@@ -7438,6 +7440,7 @@ rebase_commit(struct got_object_id **new_commit_id,
 	/* NB: commit_worktree will call free(logmsg) */
 	err = commit_worktree(new_commit_id, &commitable_paths, head_commit_id,
 	    NULL, worktree, got_object_commit_get_author(orig_commit),
+	    got_object_commit_get_author_time(orig_commit),
 	    committer ? committer :
 	    got_object_commit_get_committer(orig_commit), NULL,
 	    collect_rebase_commit_msg, logmsg, rebase_status, NULL, repo);
@@ -8753,11 +8756,10 @@ done:
 const struct got_error *
 got_worktree_merge_commit(struct got_object_id **new_commit_id,
     struct got_worktree *worktree, struct got_fileindex *fileindex,
-    const char *author, const char *committer, int allow_bad_symlinks,
-    struct got_object_id *branch_tip, const char *branch_name,
-    int allow_conflict, struct got_repository *repo,
+    const char *author, time_t author_time, const char *committer,
+    int allow_bad_symlinks, struct got_object_id *branch_tip,
+    const char *branch_name, int allow_conflict, struct got_repository *repo,
     got_worktree_status_cb status_cb, void *status_arg)
-
 {
 	const struct got_error *err = NULL, *sync_err;
 	struct got_pathlist_head commitable_paths;
@@ -8810,8 +8812,9 @@ got_worktree_merge_commit(struct got_object_id **new_c
 	mcm_arg.worktree = worktree;
 	mcm_arg.branch_name = branch_name;
 	err = commit_worktree(new_commit_id, &commitable_paths,
-	    head_commit_id, branch_tip, worktree, author, committer, NULL,
-	    merge_commit_msg_cb, &mcm_arg, status_cb, status_arg, repo);
+	    head_commit_id, branch_tip, worktree, author, author_time,
+	    committer, NULL, merge_commit_msg_cb, &mcm_arg, status_cb,
+	    status_arg, repo);
 	if (err)
 		goto done;
 
blob - 84c24828bea9475f7b0841d4f7fe0ffec5264646
blob + 98d40ea3754215fd3024137b6c6a860b8d17eca8
--- regress/cmdline/rebase.sh
+++ regress/cmdline/rebase.sh
@@ -1002,6 +1002,68 @@ test_rebase_preserves_logmsg() {
 	test_done "$testroot" "$ret"
 }
 
+test_rebase_preserves_author_data() {
+	local testroot=`test_init rebase_preserves_author_data`
+
+	git -C $testroot/repo checkout -q -b newbranch
+	echo "modified delta on branch" > $testroot/repo/gamma/delta
+	TZ=EST git_commit $testroot/repo -m "modified delta on newbranch"
+
+	sleep 1		# get a new timestamp
+	echo "modified alpha on branch" > $testroot/repo/alpha
+	TZ=CET git_commit $testroot/repo -m "modified alpha on newbranch"
+
+	local orig_commit1=`git_show_parent_commit $testroot/repo`
+	local orig_commit2=`git_show_head $testroot/repo`
+
+	(cd $testroot/repo && got cat $orig_commit1 $orig_commit2 | \
+		grep '^author ' > $testroot/author_data.expected)
+
+	git -C $testroot/repo checkout -q master
+	echo "modified zeta on master" > $testroot/repo/epsilon/zeta
+	git_commit $testroot/repo -m "committing to zeta on master"
+	local master_commit=`git_show_head $testroot/repo`
+
+	got checkout $testroot/repo $testroot/wt > /dev/null
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	sleep 1		# get a new timestamp
+	(cd $testroot/wt && got rebase newbranch > /dev/null \
+		2> $testroot/stderr)
+
+	git -C $testroot/repo checkout -q newbranch
+	local new_commit1=`git_show_parent_commit $testroot/repo`
+	local new_commit2=`git_show_head $testroot/repo`
+
+	echo -n > $testroot/stderr.expected
+	cmp -s $testroot/stderr.expected $testroot/stderr
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/stderr.expected $testroot/stderr
+		test_done "$testroot" "$ret"
+		return 1
+	fi
+
+	(cd $testroot/wt && got cat $new_commit1 $new_commit2 | \
+		grep '^author ' > $testroot/author_data)
+	# note: got deliberately clobbers the timezone to UTC, so expect that
+	ed -s $testroot/author_data.expected <<-EOF
+	,s/ [+-][0-9]\{4\}\$/ +0000/
+	w
+	EOF
+	cmp -s $testroot/author_data.expected $testroot/author_data
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		diff -u $testroot/author_data.expected $testroot/author_data
+	fi
+
+	test_done "$testroot" "$ret"
+}
+
 test_rebase_no_commits_to_rebase() {
 	local testroot=`test_init rebase_no_commits_to_rebase`
 
@@ -2286,6 +2348,7 @@ run_test test_rebase_no_op_change
 run_test test_rebase_in_progress
 run_test test_rebase_path_prefix
 run_test test_rebase_preserves_logmsg
+run_test test_rebase_preserves_author_data
 run_test test_rebase_no_commits_to_rebase
 run_test test_rebase_forward
 run_test test_rebase_forward_path_prefix