On 27/10/17 12:58 pm, Junio C Hamano wrote:
> Isabella Stephens <istephens@xxxxxxxxxxxxx> writes:
>
>> diff --git a/builtin/blame.c b/builtin/blame.c
>> index 67adaef4d..b5b9db147 100644
>> --- a/builtin/blame.c
>> +++ b/builtin/blame.c
>> @@ -878,13 +878,13 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
>> nth_line_cb, &sb, lno, anchor,
>> &bottom, &top, sb.path))
>> usage(blame_usage);
>> - if (lno < top || ((lno || bottom) && lno < bottom))
>> + if ((lno || bottom) && lno < bottom)
>> die(Q_("file %s has only %lu line",
>> "file %s has only %lu lines",
>> lno), path, lno);
>> if (bottom < 1)
>> bottom = 1;
>> - if (top < 1)
>> + if (top < 1 || lno < top)
>> top = lno;
>
> This section sanity-checks first and then tweaks the values it
> allowed to pass the check. Because it wants to later fix up an
> overly large "top" by capping to "lno" (i.e. total line number), the
> patch needs to loosen the early sanity-check. And the "fixed up"
> values are never checked if they are sane.
>
> For example, with an empty file (i.e. lno == 0), you can ask "git
> blame -L1,-4 ("i.e. "at most four lines, ending at line #1") and the
> code silently accepts the input without noticing that the request is
> an utter nonsense; "file X has only 0 lines" error is given a chance
> to kick in.
>
> There should be an "is the range sensible?" check after all the
> tweaking to bottom and top are done, I think.
My mistake. I missed that case. I think this section of code is a little
hard to read because it avoids treating an empty file as a special case.
Why not do something like this:
for (range_i = 0; range_i < range_list.nr; ++range_i) {
long bottom, top;
if (!lno)
die(_("file is empty"));
if (parse_range_arg(range_list.items[range_i].string,
nth_line_cb, &sb, lno, anchor,
&bottom, &top, sb.path))
usage(blame_usage);
if (bottom < 1)
bottom = 1;
if (lno < top)
top = lno;
if (top < 0 || lno < bottom)
die(Q_("file %s has only %lu line",
"file %s has only %lu lines",
lno), path, lno);
bottom--;
range_set_append_unsafe(&ranges, bottom, top);
anchor = top + 1;
We'd also need to change parse_range_arg to always make bottom less than top:
- if (*begin && *end && *end < *begin) {
+ if (*end < *begin) {
SWAP(*end, *begin);
}
This also fixes the case where the given range is n,-(n+1) (e.g. -L1,-2). At
the moment that will blame from n to the end of the file. My suggested change
would instead blame the first n lines, which makes a lot more sense IMO.
Happy to leave as is if you aren't happy with this suggestion, however.
