reset_head(): factor out ref updates

In the next commit we will stop trying to update HEAD when we are
removing uncommitted changes from the working tree. Move the code that
updates the refs to its own function in preparation for that.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

reset.c

@@ -8,25 +8,75 @@
 #include "tree.h"
 #include "unpack-trees.h"
 
+static int update_refs(const struct object_id *oid, const char *switch_to_branch,
+		       const struct object_id *head, const char *reflog_head,
+		       const char *reflog_orig_head,
+		       const char *default_reflog_action, unsigned flags)
+{
+	unsigned detach_head = flags & RESET_HEAD_DETACH;
+	unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
+	unsigned update_orig_head = flags & RESET_ORIG_HEAD;
+	struct object_id *old_orig = NULL, oid_old_orig;
+	struct strbuf msg = STRBUF_INIT;
+	const char *reflog_action;
+	size_t prefix_len;
+	int ret;
+
+	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
+	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : default_reflog_action);
+	prefix_len = msg.len;
+
+	if (update_orig_head) {
+		if (!get_oid("ORIG_HEAD", &oid_old_orig))
+			old_orig = &oid_old_orig;
+		if (head) {
+			if (!reflog_orig_head) {
+				strbuf_addstr(&msg, "updating ORIG_HEAD");
+				reflog_orig_head = msg.buf;
+			}
+			update_ref(reflog_orig_head, "ORIG_HEAD", head,
+				   old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
+		} else if (old_orig)
+			delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
+	}
+
+	if (!reflog_head) {
+		strbuf_setlen(&msg, prefix_len);
+		strbuf_addstr(&msg, "updating HEAD");
+		reflog_head = msg.buf;
+	}
+	if (!switch_to_branch)
+		ret = update_ref(reflog_head, "HEAD", oid, head,
+				 detach_head ? REF_NO_DEREF : 0,
+				 UPDATE_REFS_MSG_ON_ERR);
+	else {
+		ret = update_ref(reflog_head, switch_to_branch, oid,
+				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
+		if (!ret)
+			ret = create_symref("HEAD", switch_to_branch,
+					    reflog_head);
+	}
+	if (!ret && run_hook)
+		run_hook_le(NULL, "post-checkout",
+			    oid_to_hex(head ? head : null_oid()),
+			    oid_to_hex(oid), "1", NULL);
+	strbuf_release(&msg);
+	return ret;
+}
+
 int reset_head(struct repository *r, struct object_id *oid,
 	       const char *switch_to_branch, unsigned flags,
 	       const char *reflog_orig_head, const char *reflog_head,
 	       const char *default_reflog_action)
 {
-	unsigned detach_head = flags & RESET_HEAD_DETACH;
 	unsigned reset_hard = flags & RESET_HEAD_HARD;
-	unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
 	unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
-	unsigned update_orig_head = flags & RESET_ORIG_HEAD;
 	struct object_id *head = NULL, head_oid;
 	struct tree_desc desc[2] = { { NULL }, { NULL } };
 	struct lock_file lock = LOCK_INIT;
 	struct unpack_trees_options unpack_tree_opts = { 0 };
 	struct tree *tree;
-	const char *action, *reflog_action;
-	struct strbuf msg = STRBUF_INIT;
-	size_t prefix_len;
-	struct object_id *old_orig = NULL, oid_old_orig;
+	const char *action;
 	int ret = 0, nr = 0;
 
 	if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
@@ -48,7 +98,9 @@ int reset_head(struct repository *r, struct object_id *oid,
 		oid = &head_oid;
 
 	if (refs_only)
-		goto reset_head_refs;
+		return update_refs(oid, switch_to_branch, head, reflog_head,
+				   reflog_orig_head, default_reflog_action,
+				   flags);
 
 	action = reset_hard ? "reset" : "checkout";
 	setup_unpack_trees_porcelain(&unpack_tree_opts, action);
@@ -92,48 +144,10 @@ int reset_head(struct repository *r, struct object_id *oid,
 		goto leave_reset_head;
 	}
 
-reset_head_refs:
-	reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
-	strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : default_reflog_action);
-	prefix_len = msg.len;
-
-	if (update_orig_head) {
-		if (!get_oid("ORIG_HEAD", &oid_old_orig))
-			old_orig = &oid_old_orig;
-		if (head) {
-			if (!reflog_orig_head) {
-				strbuf_addstr(&msg, "updating ORIG_HEAD");
-				reflog_orig_head = msg.buf;
-			}
-			update_ref(reflog_orig_head, "ORIG_HEAD", head,
-				   old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
-		} else if (old_orig)
-			delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
-	}
-
-	if (!reflog_head) {
-		strbuf_setlen(&msg, prefix_len);
-		strbuf_addstr(&msg, "updating HEAD");
-		reflog_head = msg.buf;
-	}
-	if (!switch_to_branch)
-		ret = update_ref(reflog_head, "HEAD", oid, head,
-				 detach_head ? REF_NO_DEREF : 0,
-				 UPDATE_REFS_MSG_ON_ERR);
-	else {
-		ret = update_ref(reflog_head, switch_to_branch, oid,
-				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
-		if (!ret)
-			ret = create_symref("HEAD", switch_to_branch,
-					    reflog_head);
-	}
-	if (!ret && run_hook)
-		run_hook_le(NULL, "post-checkout",
-			    oid_to_hex(head ? head : null_oid()),
-			    oid_to_hex(oid), "1", NULL);
+	ret = update_refs(oid, switch_to_branch, head, reflog_head,
+			  reflog_orig_head, default_reflog_action, flags);
 
 leave_reset_head:
-	strbuf_release(&msg);
 	rollback_lock_file(&lock);
 	clear_unpack_trees_porcelain(&unpack_tree_opts);
 	while (nr)