Junio C Hamano <gitster@xxxxxxxxx> writes:
> Lidong Yan <yldhome2d2@xxxxxxxxx> writes:
>
>> Remove `if (spec->nr > 1)` to enable bloom filter given multiple
>> pathspec. Wrapped for loop around code in prepare_to_use_bloom_filter()
>> to initialize each pathspec's struct bloom_keyvec. Add for loop
>> in check_maybe_different_in_bloom_filter() to find if at least one
>> pathspec's bloom_keyvec is contained in bloom filter.
>
> Oy. That's too dense enumeration but I suspect are all "what the
> patch does" that can be read from the diff. The first sentence
> gives "why", which is excellent.
Got it. I will simply this log message in next version.
> You'd need to check in forbid_bloom_filters() that none of the
> pathspec items have magic (other than literal), not just the first
> one, no?
Yeah, I never notice that. I would add checks in forbid_bloom_filters().
And add test to ensure we don’t use bloom filter if any pathspec item is
not literal.
> Totally outside the topic, but I wonder if we can further optimize
> by adding an early rejection using .nowildcard_len? Instead of
> allowing a wildcarded "dir/*" pathspec element from disabling the
> Bloom filter altogether, we could say "dir/ is not possibly altered,
> so there may be dir/A, dir/B, etc., in the directory, nothing that
> would match dir/* wildcard would have been modified", couldn't we?
>
I think it's feasible. In that case, we would need to add a condition
.nowildcard_len > 0 to forbid_bloom_filter. I'm happy to write a new
patch to address this issue.
>> diff --git a/revision.c b/revision.c
>> index cf7dc3b3fa..8818f017f3 100644
>> --- a/revision.c
>> +++ b/revision.c
>> @@ -675,8 +675,6 @@ static int forbid_bloom_filters(struct pathspec *spec)
>> {
>> if (spec->has_wildcard)
>> return 1;
>> - if (spec->nr > 1)
>> - return 1;
>> if (spec->magic & ~PATHSPEC_LITERAL)
>> return 1;
>> if (spec->nr && (spec->items[0].magic & ~PATHSPEC_LITERAL))
>
> This last check only looks at the first item. It used to be OK
> because we didn't look at a pathspec with more than one element, but
> now shouldn't we care?
Definitely, I would fix that in 3rd version.
Thanks,
Lidong
