delete_ref(): handle special case more explicitly

diff --git a/refs.c b/refs.c
index a742d7925dfbd08ff7623427b74183406fdb85ec..9b7bdd4198efe43d4eec0c149e7d3127ffd354cc 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2219,27 +2219,35 @@ static void unlock_ref(struct ref_lock *lock)
        free(lock);
 }
 
-/* This function should make sure errno is meaningful on error */
-static struct ref_lock *verify_lock(struct ref_lock *lock,
-       const unsigned char *old_sha1, int mustexist)
+/*
+ * Verify that the reference locked by lock has the value old_sha1.
+ * Fail if the reference doesn't exist and mustexist is set. Return 0
+ * on success. On error, write an error message to err, set errno, and
+ * return a negative value.
+ */
+static int verify_lock(struct ref_lock *lock,
+                      const unsigned char *old_sha1, int mustexist,
+                      struct strbuf *err)
 {
+       assert(err);
+
        if (read_ref_full(lock->ref_name,
                          mustexist ? RESOLVE_REF_READING : 0,
                          lock->old_oid.hash, NULL)) {
                int save_errno = errno;
-               error("Can't verify ref %s", lock->ref_name);
-               unlock_ref(lock);
+               strbuf_addf(err, "can't verify ref %s", lock->ref_name);
                errno = save_errno;
-               return NULL;
+               return -1;
        }
        if (hashcmp(lock->old_oid.hash, old_sha1)) {
-               error("Ref %s is at %s but expected %s", lock->ref_name,
-                       oid_to_hex(&lock->old_oid), sha1_to_hex(old_sha1));
-               unlock_ref(lock);
+               strbuf_addf(err, "ref %s is at %s but expected %s",
+                           lock->ref_name,
+                           sha1_to_hex(lock->old_oid.hash),
+                           sha1_to_hex(old_sha1));
                errno = EBUSY;
-               return NULL;
+               return -1;
        }
-       return lock;
+       return 0;
 }
 
 static int remove_empty_directories(const char *file)
@@ -2467,7 +2475,11 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
                        goto error_return;
                }
        }
-       return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
+       if (old_sha1 && verify_lock(lock, old_sha1, mustexist, err)) {
+               last_errno = errno;
+               goto error_return;
+       }
+       return lock;
 
  error_return:
        unlock_ref(lock);
@@ -2789,15 +2801,23 @@ static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
        return 0;
 }
 
-int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
+int delete_ref(const char *refname, const unsigned char *old_sha1,
+              unsigned int flags)
 {
        struct ref_transaction *transaction;
        struct strbuf err = STRBUF_INIT;
 
+       /*
+        * Treat NULL_SHA1 and NULL alike, to mean "we don't care what
+        * the old value of the reference was (or even if it didn't
+        * exist)":
+        */
+       if (old_sha1 && is_null_sha1(old_sha1))
+               old_sha1 = NULL;
+
        transaction = ref_transaction_begin(&err);
        if (!transaction ||
-           ref_transaction_delete(transaction, refname,
-                                  (sha1 && !is_null_sha1(sha1)) ? sha1 : NULL,
+           ref_transaction_delete(transaction, refname, old_sha1,
                                   flags, NULL, &err) ||
            ref_transaction_commit(transaction, &err)) {
                error("%s", err.buf);
@@ -3912,7 +3932,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                                ? TRANSACTION_NAME_CONFLICT
                                : TRANSACTION_GENERIC_ERROR;
                        reason = strbuf_detach(err, NULL);
-                       strbuf_addf(err, "Cannot lock ref '%s': %s",
+                       strbuf_addf(err, "cannot lock ref '%s': %s",
                                    update->refname, reason);
                        free(reason);
                        goto cleanup;
@@ -3935,7 +3955,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                                 * write_ref_to_lockfile():
                                 */
                                update->lock = NULL;
-                               strbuf_addf(err, "Cannot update the ref '%s'.",
+                               strbuf_addf(err, "cannot update the ref '%s'.",
                                            update->refname);
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;