Am 19.05.20 um 14:11 schrieb Derrick Stolee:
> On 5/15/2020 1:22 PM, Derrick Stolee wrote:
>> René Scharfe 9068cfb2 fsck: report non-consecutive duplicate names in trees
>> fsck.c
>> 9068cfb2 623) break;
>> 9068cfb2 626) if (is_less_than_slash(*p)) {
>> 9068cfb2 627) name_stack_push(candidates, f_name);
>> 9068cfb2 628) break;
>> 9068cfb2 630) }
>
> These are different conditions in verify_ordered() to check the
> special case of blobs and trees having the "same" name (but
> sorted differently due to appending '/' to trees before sorting).
>
> There is another name_stack_push() that _is_ covered. I wonder
> what case would trigger this push?
Our test has one entry between the conflicting two:
x
x.1
x/
The branch is necessary if the check of a candidate tree consumes
a candidate file from the stack that we need to check against later
candidate trees, e.g.:
x
x.1.2
x.1/
x/
Let's check each in sequence:
1. "x" is a candidate file because the next entry starts with "x" +
less-than-slash, so "x/" can still follow. We push it onto the
stack.
2. "x.1.2" is not a candidate. A hypothetical "x.1.2/" would come
before "x.1/", so we can be sure we don't have it.
3. "x.1/" is a candidate tree because it follows an entry that starts
with "x.1" + less-than-slash, so we could have seen a file named
"x.1" earlier. We pop "x" from the stack and see that it doesn't
match, but is a prefix. "x.1/" is "x" + less-than-slash, so "x/"
can still follow. We push it back onto the stack. And that's
the branch in question.
4. "x/" is a candidate tree because it follows an entry that starts
with "x" + less-than-slash, so we could have seen a file named "x"
earlier. We pop "x" from the stack, and have a match.
But here's one that slips by fsck and the test coverage check:
x
x.1
x.1.2
x/
This duplicate is not caught by the current code. Both "x" and "x.1"
are candidate files. "x.1.2" is not a candidate. "x/" is checked
against "x.1" from the top of the stack, found not to be a prefix and
the search ends at that point, unsuccessfully. I think we need this to
fix it:
diff --git a/fsck.c b/fsck.c
index 8bb3ecf282..594e800015 100644
--- a/fsck.c
+++ b/fsck.c
@@ -620,7 +620,7 @@ static int verify_ordered(unsigned mode1, const char *name1,
if (!f_name)
break;
if (!skip_prefix(name2, f_name, &p))
- break;
+ continue;
if (!*p)
return TREE_HAS_DUPS;
if (is_less_than_slash(*p)) {
