Re: [PATCH 04/12] diff: fix incorrect counting of line numbers

> Phillip Wood <phillip.wood123@gmail.com> writes:
>> On 04/11/2025 02:09, Junio C Hamano wrote:
>>
>> The "\ No newline at end of file" line is an annotation on the previous
>> line in the diff so why are we incrementing any {pre,post}image line
>> numbers here?
> 
> No particular reason ;-)  As I said, I do not think these numbers
> are used after these lines are seen.  At least this change makes
> these unused data incremented in a more coherent way than the
> previous one, which unconditionally incremented the number for the
> preimage without even checking which side the "\ No newline" is for.

>> Thanks
>>
>> Phillip
>>
>>> Signed-off-by: Junio C Hamano <gitster@pobox.com>
>>> ---
>>>    diff.c | 18 +++++++++++++++++-
>>>    1 file changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/diff.c b/diff.c
>>> index b9ef8550cc..e73320dfb1 100644
>>> --- a/diff.c
>>> +++ b/diff.c
>>> @@ -601,6 +601,7 @@ struct emit_callback {
>>>    	int blank_at_eof_in_postimage;
>>>    	int lno_in_preimage;
>>>    	int lno_in_postimage;
>>> +	int last_line_kind;
>>>    	const char **label_path;
>>>    	struct diff_words_data *diff_words;
>>>    	struct diff_options *opt;
>>> @@ -2426,13 +2427,28 @@ static int fn_out_consume(void *priv, char *line, unsigned long len)
>>>    		break;
>>>    	case '\\':
>>>    		/* incomplete line at the end */
>>> -		ecbdata->lno_in_preimage++;
>>> +		switch (ecbdata->last_line_kind) {
>>> +		case '+':
>>> +			ecbdata->lno_in_postimage++;
>>> +			break;
>>> +		case '-':
>>> +			ecbdata->lno_in_preimage++;
>>> +			break;
>>> +		case ' ':
>>> +			ecbdata->lno_in_preimage++;
>>> +			ecbdata->lno_in_postimage++;
>>> +			break;
>>> +		default:
>>> +			BUG("fn_out_consume: '\\No newline' after unknown line (%c)",
>>> +			    ecbdata->last_line_kind);
>>> +		}
>>>    		emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
>>>    				 line, len, 0);
>>>    		break;
>>>    	default:
>>>    		BUG("fn_out_consume: unknown line '%s'", line);
>>>    	}
>>> +	ecbdata->last_line_kind = line[0];
>>>    	return 0;
>>>    }
>>>