On Tue, Jul 31, 2018 at 7:15 AM Phillip Wood <phillip.wood@xxxxxxxxxxxx> wrote:
> The calling code treated NULL as a valid return value, so fix this by
> returning and integer and passing in a parameter to receive the author.
It might be difficult for future readers (those who didn't follow the
discussion) to understand how/why NULL is not sufficient to signal an
error. Perhaps incorporating the explanation from your email[1] which
discussed that the author name, email, and/or date might change
unexpectedly would be sufficient. This excerpt from [1] might be a
good starting point:
... the caller does not treat NULL as an error, so this will
change the date and potentially the author of the commit
... [which] does corrupt the author data compared to its
expected value.
[1]: https://public-inbox.org/git/c80cf729-1bbe-10f5-6837-b074d371b91c@xxxxxxxxxxxx/
> Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
> ---
> diff --git a/sequencer.c b/sequencer.c
> @@ -701,57 +701,58 @@ static char *get_author(const char *message)
> -static const char *read_author_ident(struct strbuf *buf)
> +static int read_author_ident(char **author)
So, the caller is now responsible for freeing the string placed in
'author'. Okay.
> {
> - if (strbuf_read_file(buf, rebase_path_author_script(), 256) <= 0)
> - return NULL;
> + if (strbuf_read_file(&buf, rebase_path_author_script(), 256) <= 0)
> + return -1;
I think you need to strbuf_release(&buf) in this error path since
strbuf_read_file() doesn't guarantee that the strbuf hasn't been
partially populated when it returns an error. (That is, this is
leaking.)
> /* dequote values and construct ident line in-place */
Ugh, this comment should have been adjusted in my series. A minor
matter, though, which can be tweaked later.
> /* validate date since fmt_ident() will die() on bad value */
> if (parse_date(val[2], &out)){
> - warning(_("invalid date format '%s' in '%s'"),
> + error(_("invalid date format '%s' in '%s'"),
> val[2], rebase_path_author_script());
> strbuf_release(&out);
> - return NULL;
> + strbuf_release(&buf);
> + return -1;
You were careful to print the error, which references a value from
'buf', before destroying 'buf'. Good.
(A simplifying alternative would have been to not print the actual
value and instead say generally that "the date" was bad. Not a big
deal.)
> }
> - strbuf_swap(buf, &out);
> - strbuf_release(&out);
> - return buf->buf;
> + *author = strbuf_detach(&out, NULL);
And, 'author' is only assigned when 0 is returned, so the caller only
has to free(author) upon success. Fine.
> + strbuf_release(&buf);
> + return 0;
> }
>
> static const char staged_changes_advice[] =
> @@ -794,12 +795,14 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
> - struct strbuf msg = STRBUF_INIT, script = STRBUF_INIT;
> - const char *author = is_rebase_i(opts) ?
> - read_author_ident(&script) : NULL;
> + struct strbuf msg = STRBUF_INIT;
> + char *author = NULL;
> struct object_id root_commit, *cache_tree_oid;
> int res = 0;
>
> + if (is_rebase_i(opts) && read_author_ident(&author))
> + return -1;
Logic looks correct, and it's nice to see that you went with 'return
-1' rather than die(), especially since the caller of run_git_commit()
is already able to handle -1.
