refs.c: do not permit err == NULL

Some functions that take a strbuf argument to append an error treat
!err as an indication that the message should be suppressed (e.g.,
ref_update_reject_duplicates).  Others write the message to stderr on
!err (e.g., repack_without_refs).  Others crash (e.g.,
ref_transaction_update).

Some of these behaviors are for historical reasons and others were
accidents.  Luckily no callers pass err == NULL any more.  Simplify
by consistently requiring the strbuf argument.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index e7000f2cb202ea41b429b1bd68f3a05fe2f0a1f9..097fb4b60ef5e0f84d13b088fa13dea09c58f538 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2646,6 +2646,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
        struct string_list_item *ref_to_delete;
        int i, ret, removed = 0;
 
+       assert(err);
+
        /* Look for a packed ref */
        for (i = 0; i < n; i++)
                if (get_packed_ref(refnames[i]))
@@ -2656,13 +2658,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
                return 0; /* no refname exists in packed refs */
 
        if (lock_packed_refs(0)) {
-               if (err) {
-                       unable_to_lock_message(git_path("packed-refs"), errno,
-                                              err);
-                       return -1;
-               }
-               unable_to_lock_error(git_path("packed-refs"), errno);
-               return error("cannot delete '%s' from packed refs", refnames[i]);
+               unable_to_lock_message(git_path("packed-refs"), errno, err);
+               return -1;
        }
        packed = get_packed_refs(&ref_cache);
 
@@ -2688,7 +2685,7 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
        /* Write what remains */
        ret = commit_packed_refs();
-       if (ret && err)
+       if (ret)
                strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
                            strerror(errno));
        return ret;
@@ -2696,6 +2693,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 {
+       assert(err);
+
        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
                /*
                 * loose.  The loose file name is the same as the
@@ -3551,6 +3550,8 @@ struct ref_transaction {
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
+       assert(err);
+
        return xcalloc(1, sizeof(struct ref_transaction));
 }
 
@@ -3590,6 +3591,8 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: update called for transaction that is not open");
 
@@ -3622,6 +3625,8 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: create called for transaction that is not open");
 
@@ -3653,6 +3658,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
        struct ref_update *update;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: delete called for transaction that is not open");
 
@@ -3715,13 +3722,14 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
                                        struct strbuf *err)
 {
        int i;
+
+       assert(err);
+
        for (i = 1; i < n; i++)
                if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
-                       const char *str =
-                               "Multiple updates for ref '%s' not allowed.";
-                       if (err)
-                               strbuf_addf(err, str, updates[i]->refname);
-
+                       strbuf_addf(err,
+                                   "Multiple updates for ref '%s' not allowed.",
+                                   updates[i]->refname);
                        return 1;
                }
        return 0;
@@ -3735,6 +3743,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        int n = transaction->nr;
        struct ref_update **updates = transaction->updates;
 
+       assert(err);
+
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: commit called for transaction that is not open");
 
@@ -3771,9 +3781,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                        ret = (errno == ENOTDIR)
                                ? TRANSACTION_NAME_CONFLICT
                                : TRANSACTION_GENERIC_ERROR;
-                       if (err)
-                               strbuf_addf(err, "Cannot lock the ref '%s'.",
-                                           update->refname);
+                       strbuf_addf(err, "Cannot lock the ref '%s'.",
+                                   update->refname);
                        goto cleanup;
                }
        }
@@ -3786,9 +3795,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                        if (write_ref_sha1(update->lock, update->new_sha1,
                                           update->msg)) {
                                update->lock = NULL; /* freed by write_ref_sha1 */
-                               if (err)
-                                       strbuf_addf(err, "Cannot update the ref '%s'.",
-                                                   update->refname);
+                               strbuf_addf(err, "Cannot update the ref '%s'.",
+                                           update->refname);
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }