Re: [PATCH v2] cache-tree: invalidate i-t-a paths after generating trees

> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
>
>> diff --git a/cache-tree.c b/cache-tree.c
>> index 28ed657..989a7ff 100644
>> --- a/cache-tree.c
>> +++ b/cache-tree.c
>> @@ -248,6 +248,7 @@ static int update_one(struct cache_tree *it,
>>       int missing_ok = flags & WRITE_TREE_MISSING_OK;
>>       int dryrun = flags & WRITE_TREE_DRY_RUN;
>>       int i;
>> +     int to_invalidate = 0;
>>
>>       if (0 <= it->entry_count && has_sha1_file(it->sha1))
>>               return it->entry_count;
>> @@ -324,7 +325,13 @@ static int update_one(struct cache_tree *it,
>>                       if (!sub)
>>                               die("cache-tree.c: '%.*s' in '%s' not found",
>>                                   entlen, path + baselen, path);
>> -                     i += sub->cache_tree->entry_count - 1;
>> +                     i--; /* this entry is already counted in "sub" */
>> +                     if (sub->cache_tree->entry_count < 0) {
>> +                             i -= sub->cache_tree->entry_count;
>> +                             to_invalidate = 1;
>> +                     }
>> +                     else
>> +                             i += sub->cache_tree->entry_count;
>
> Hrm.  update_one() is prepared to see a cache-tree whose entry count
> is zero (see the context lines in the previous hunk) and the
> invariant for the rest of the code is "if 0 <= entry_count, the
> cached tree is valid; invalid cache-tree has -1 in entry_count.
> More importantly, entry_count negated does not in general express
> how many entries there are in the subtree and does not tell us how
> many index entries to skip.

>> +                     if (sub->cache_tree->entry_count < 0) {
>> +                             i -= sub->cache_tree->entry_count;
>> +                             sub->cache_tree->entry_count = -1;
>> +                             to_invalidate = 1;
>> +                     }