Re: [PATCH 1/3] wt-status: implement opportunisitc index update correctly

> Stefan Beller <sbeller@google.com> writes:
>
>> So my first question I had to answer was if we do the right thing here,
>> i.e. if we could just fail instead. But we want to continue and just
>> not write back the index, which is fine.
>>
>> So we do not have to guard refresh_cache, but just call
>> update_index_if_able conditionally.
>
> An explanation with stepping back a little bit may help.
>
> You may be asked to visit a repository of a friend, to which you do
> not have write access to but you can still read.  You may want to do
> "diff", "status" or "describe" there.
>
> In order to avoid getting fooled into thinking some paths are dirty
> only because the cached stat information does not match, these need
> to refresh the in-core index before doing their "comparison" to
> report which paths are different (in "diff"), what are the modified
> but not staged paths (in "status"), and if there is a need to add
> the "-dirty" suffix (in "describe").
>
> Since we are doing the expensive "bunch of lstat()" anyway, if we
> could write it back to the index, it would help future operations in
> the same repository--that is the reasoning behind the opportunistic
> updates.  It is perfectly OK if we do not have write access to the
> repository and cannot write update the index.
>