refs.c: make ref_transaction_begin take an err argument

Add an err argument to _begin so that on non-fatal failures in future ref
backends we can report a nice error back to the caller.
While _begin can currently never fail for other reasons than OOM, in which
case we die() anyway, we may add other types of backends in the future.
For example, a hypothetical MySQL backend could fail in _begin with
"Can not connect to MySQL server. No route to host".

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

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 7c9c248e54195ae49a9f03a8770a295bc6e7f320..96a53b92aed97142996c1071555e85bdcb333987 100644 (file)
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -365,7 +365,9 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
                die("Refusing to perform update with empty message.");
 
        if (read_stdin) {
-               transaction = ref_transaction_begin();
+               transaction = ref_transaction_begin(&err);
+               if (!transaction)
+                       die("%s", err.buf);
                if (delete || no_deref || argc > 0)
                        usage_with_options(git_update_ref_usage, options);
                if (end_null)
@@ -374,6 +376,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
                if (ref_transaction_commit(transaction, msg, &err))
                        die("%s", err.buf);
                ref_transaction_free(transaction);
+               strbuf_release(&err);
                return 0;
        }
 

diff --git a/refs.c b/refs.c
index 40f04f4a6f40d2b3ffd4ade344a5cf2c0d45c6ee..9cb79081b5b7edcb0d40cf6f689e6f6d61606f53 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -3397,7 +3397,7 @@ struct ref_transaction {
        size_t nr;
 };
 
-struct ref_transaction *ref_transaction_begin(void)
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
        return xcalloc(1, sizeof(struct ref_transaction));
 }

diff --git a/refs.h b/refs.h
index 71389a1f888ea02ec159d235a245181dba10e9ea..3f37c6509291ef3972cecd1adfb1fd2dd649a698 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -262,7 +262,7 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
-struct ref_transaction *ref_transaction_begin(void);
+struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
  * The following functions add a reference check or update to a