Re: [PATCH v2 0/6] Fast git status via a file system watcher

[Ben Peart <peartben@gmail.com>]

On 5/24/2017 6:54 AM, Christian Couder wrote:
>> Design
>> ~~~~~~
>>
>> A new git hook (query-fsmonitor) must exist and be enabled
>> (core.fsmonitor=true) that takes a time_t formatted as a string and
>> outputs to stdout all files that have been modified since the requested
>> time.
> 
> Is there a reason why there is a new hook, instead of a
> "core.fsmonitorquery" config option to which you could pass whatever
> command line with options?

A hook is a simple and well defined way to integrate git with another 
process.  If there is some fixed set of arguments that need to be passed 
to a file system monitor (beyond the timestamp stored in the index 
extension), they can be encoded in the integration script like I've done 
in the Watchman integration sample hook.

> 
>> A new 'fsmonitor' index extension has been added to store the time the
>> fsmonitor hook was last queried and a ewah bitmap of the current
>> 'fsmonitor-dirty' files. Unmarked entries are 'fsmonitor-clean', marked
>> entries are 'fsmonitor-dirty.'
>>
>> As needed, git will call the query-fsmonitor hook proc for the set of
>> changes since the index was last updated. Git then uses this set of
>> files along with the list saved in the fsmonitor index extension to flag
>> the potentially dirty index and untracked cache entries.
> 
> So this can work only if "core.untrackedCache" is set to true?
> 

This works with core.untrackedCache set to true or false.  If it is set 
to false, you get valid results, you just don't get the speed up when 
checking for untracked files.

> Thanks for working on this,
> Christian.
>