Re: [PATCH 2/3] revision: add --grep-reflog to filter commits by reflog messages

>> +	if (opt->reflog_info) {
>> +		strbuf_addstr(&buf, "reflog ");
>> +		get_reflog_message(&buf, opt->reflog_info);
>> +		strbuf_addch(&buf, '\n');
>> +		strbuf_addstr(&buf, commit->buffer);
>> +	}
>> +	if (buf.len)
>> +		retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
>> +	else
>> +		retval = grep_buffer(&opt->grep_filter,
>> +				     commit->buffer, strlen(commit->buffer));
>> +	strbuf_release(&buf);
>> +	return retval;
>
> I like how callers not doing a reflog walk do not have to pay the price
> to do the extra allocating. We could further limit it to only when
> --grep-reflog is in effect, but I guess that would mean wading through
> grep_filter's patterns, since it could be buried amidst ANDs and ORs?
>
> One alternative would be to set a bit in the grep_opt when we call
> append_header_grep_pattern. It feels a bit like a layering violation,
> though. I guess the bit could also go into rev_info. It may not even be
> a measurable slowdown, though. Premature optimization and all that.