Hi Junio
On 18/07/2024 17:29, Junio C Hamano wrote:
"Phillip Wood via GitGitGadget" <gitgitgadget@xxxxxxxxx> writes:
From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
When "add -p" parses diffs, it looks for context lines starting with a
single space. But when diff.suppressBlankEmpty is in effect, an empty
context line will omit the space, giving us a true empty line. This
confuses the parser, which is unable to split based on such a line.
It's tempting to say that we should just make sure that we generate a
diff without that option. However, although we do not parse hunks that
the user has manually edited with parse_diff() we do allow the user
to split such hunks. As POSIX calls the decision of whether to print the
space here "implementation-defined" we need to handle edited hunks where
empty context lines omit the space.
So let's handle both cases: a context line either starts with a space or
consists of a totally empty line by normalizing the first character to a
space when we parse them. Normalizing the first character rather than
changing the code to check for a space or newline will hopefully future
proof against introducing similar bugs if the code is changed.
Reported-by: Ilya Tumaykin <itumaykin@xxxxxxxxx>
Helped-by: Jeff King <peff@xxxxxxxx>
Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
---
Well written. Thanks for a pleasant read.
Thanks to Peff for letting me steal his commit message
@@ -953,7 +960,7 @@ static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
context_line_count = 0;
while (splittable_into > 1) {
- ch = s->plain.buf[current];
+ ch = normalize_marker(s->plain.buf + current);
I wondered if &s->plain.buf[current] is easier to grok, but what's
written already is good enough ;-)
Yes I think that would be better
There is another explicit mention of ' ' in merge_hunks(). Unless
we are normalizing the buffer here (which I do not think we do),
wouldn't we have to make sure that the code over there also knows
that an empty line in a patch is an unmodified empty line?
if (plain[overlap_end] != ' ')
return error(_("expected context line "
"#%d in\n%.*s"),
Oh dear, I'm not sure how I missed that. I'll fix that and update the
test to make sure it exercises that code path as well.
Thanks for your comments
Phillip
