Re: [PATCH v8 10/44] refs.c: change ref_transaction_update() to do error checking and return status

On Thu, May 15, 2014 at 12:34 PM, Jonathan Nieder [off-list ref] wrote:

Ronnie Sahlberg wrote:

quoted

Update ref_transaction_update() do some basic error checking and return
non-zero on error. Update all callers to check ref_transaction_update() for
error. There are currently no conditions in _update that will return error but
there will be in the future.

Probably worth passing a 'struct strbuf *err' argument.  Then callers
can do

                die("%s", err.buf);

Done.

and the error message can say which ref and whether we were trying to
create a ref, or delete one, or whatever.

quoted

--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c

@@ -197,8 +197,9 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
      if (*next != line_termination)
              die("update %s: extra input: %s", refname, next);

-     ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-                            update_flags, have_old);
+     if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
+                                update_flags, have_old))
+             die("update %s: failed", refname);

This could say

                die("update %s: %s", refname, err.buf);

Done.

to give context about which command it was trying to execute.

[...]

quoted

@@ -286,8 +287,9 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
      if (*next != line_termination)
              die("verify %s: extra input: %s", refname, next);

-     ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-                            update_flags, have_old);
+     if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
+                                update_flags, have_old))
+             die("failed transaction update for %s", refname);

And this could say

                die("verify %s: %s", refname, err.buf);

Done.

[...]

quoted

--- a/refs.h
+++ b/refs.h

@@ -242,12 +242,15 @@ void ref_transaction_rollback(struct ref_transaction *transaction);
  * be deleted.  If have_old is true, then old_sha1 holds the value
  * that the reference should have had before the update, or zeros if
  * it must not have existed beforehand.
+ * Function returns 0 on success and non-zero on failure. A failure to update
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
+ */

Thanks for this documentation.