commit 1df1761f7094815d15b11a908b2132ca58169fea
from: Stefan Sperling <stsp@stsp.name>
date: Fri Jun 16 08:58:13 2023 UTC

make gotd show relevant commit hashes in error message if ref-updates collide

commit - f8780fee7a5de8db320833efc4a30aa1ad3814e2
commit + 1df1761f7094815d15b11a908b2132ca58169fea
blob - 8f6b8985f8c929a7a85fd139238d5a1481b1fe84
blob + 2818e0cdca9ab6d00ae35b461e2289cb82f51255
--- gotd/session.c
+++ gotd/session.c
@@ -410,6 +410,8 @@ update_ref(int *shut, struct gotd_session_client *clie
 	char *refname = NULL;
 	size_t datalen;
 	int locked = 0;
+	char hex1[SHA1_DIGEST_STRING_LENGTH];
+	char hex2[SHA1_DIGEST_STRING_LENGTH];
 
 	log_debug("update-ref from uid %d", client->euid);
 
@@ -451,10 +453,17 @@ update_ref(int *shut, struct gotd_session_client *clie
 			if (err)
 				goto done;
 		} else {
+			err = got_ref_resolve(&id, repo, ref);
+			if (err)
+				goto done;
+			got_object_id_hex(&new_id, hex1, sizeof(hex1));
+			got_object_id_hex(id, hex2, sizeof(hex2));
 			err = got_error_fmt(GOT_ERR_REF_BUSY,
-			    "%s has been created by someone else "
-			    "while transaction was in progress",
-			    got_ref_get_name(ref));
+			    "Addition %s: %s failed; %s: %s has been "
+			    "created by someone else while transaction "
+			    "was in progress",
+			    got_ref_get_name(ref), hex1,
+			    got_ref_get_name(ref), hex2);
 			goto done;
 		}
 	} else if (iref.delete_ref) {
@@ -468,10 +477,14 @@ update_ref(int *shut, struct gotd_session_client *clie
 			goto done;
 
 		if (got_object_id_cmp(id, &old_id) != 0) {
+			got_object_id_hex(&old_id, hex1, sizeof(hex1));
+			got_object_id_hex(id, hex2, sizeof(hex2));
 			err = got_error_fmt(GOT_ERR_REF_BUSY,
-			    "%s has been modified by someone else "
-			    "while transaction was in progress",
-			    got_ref_get_name(ref));
+			    "Deletion %s: %s failed; %s: %s has been "
+			    "created by someone else while transaction "
+			    "was in progress",
+			    got_ref_get_name(ref), hex1,
+			    got_ref_get_name(ref), hex2);
 			goto done;
 		}
 
@@ -492,10 +505,14 @@ update_ref(int *shut, struct gotd_session_client *clie
 			goto done;
 
 		if (got_object_id_cmp(id, &old_id) != 0) {
+			got_object_id_hex(&old_id, hex1, sizeof(hex1));
+			got_object_id_hex(id, hex2, sizeof(hex2));
 			err = got_error_fmt(GOT_ERR_REF_BUSY,
-			    "%s has been modified by someone else "
-			    "while transaction was in progress",
-			    got_ref_get_name(ref));
+			    "Update %s: %s failed; %s: %s has been "
+			    "created by someone else while transaction "
+			    "was in progress",
+			    got_ref_get_name(ref), hex1,
+			    got_ref_get_name(ref), hex2);
 			goto done;
 		}