Re: [PATCH 1/3] traverse_trees(): allow pruning with pathspec

[Michael Haggerty <mhagger@alum.mit.edu>]

On 10/09/2011 11:35 PM, Nguyen Thai Ngoc Duy wrote:
> On Mon, Oct 10, 2011 at 2:39 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> On 08/29/2011 11:33 PM, Junio C Hamano wrote:
>>> diff --git a/tree-walk.c b/tree-walk.c
>>> index 33f749e..808bb55 100644
>>> --- a/tree-walk.c
>>> +++ b/tree-walk.c
>>> [...]
>>> @@ -376,16 +396,22 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
>>>                       mask |= 1ul << i;
>>>                       if (S_ISDIR(entry[i].mode))
>>>                               dirmask |= 1ul << i;
>>> +                     e = &entry[i];
>>>               }
>>>               if (!mask)
>>>                       break;
>>> -             ret = info->fn(n, mask, dirmask, entry, info);
>>> -             if (ret < 0) {
>>> -                     error = ret;
>>> -                     if (!info->show_all_errors)
>>> -                             break;
>>> +             interesting = prune_traversal(e, info, &base, interesting);
>>
>> According to gcc 4.2.4 (though, strangely, not gcc 4.4.3):

I checked this a bit more carefully.  gcc 4.2.4 emits a warning when the
-O1 or -O2 optimization levels are used, but not with -O0.  gcc 4.4.3
does not emit a warning regardless of optimization level.

>> tree-walk.c: In function ‘traverse_trees’:
>> tree-walk.c:347: warning: ‘e’ may be used uninitialized in this function
> 
> False alarm. If e is not initialized in the for loop, mask would be
> zero and therefore prune_traversal(e, info, &base, interesting), which
> would use uninitialized "e", would never be called.

That's good to know.  Still, it might be worthwhile to initialize the
variable explicitly to avoid future confusion.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/