[PATCH 3 of 3] tags: preserve filtered .hgtags filenodes in tags cache (issue4550)

[Pierre-Yves David]

On 02/24/2015 09:11 AM, Gregory Szorc wrote:
> # HG changeset patch
> # User Gregory Szorc<gregory.szorc at gmail.com>
> # Date 1424769075 28800
> #      Tue Feb 24 01:11:15 2015 -0800
> # Branch stable
> # Node ID 7f1904705c29ebe7de3874f2f03c42e261ed1c96
> # Parent  7d72752b8da5bb2482e6eac47545a78ed3fff592
> tags: preserve filtered .hgtags filenodes in tags cache (issue4550)

It is clear that we need some filter awareness for tags.

However, the level of filter impact what are heads and therefore what 
file version-s- of .hgtags are considered. Therefore it seems strange to 
me that you have been able to build a solution that take filter into 
account -after- the tags have been computed.

So either:
- I missed something in your patch which is quite complexe
- I missed something in my understanding of the issue
- There is something wrong with this patch.

Please find which of this options is true ;-)

Out of my head I would expect we need a "one cache file per filter" 
approach as we have for branch heads. We had a related discussion in 
Munich where you sugguested to cache different step of the operation so 
that we do not need to unpack manifest for all heads when computing 
tags. This could help to share computation between each filter level.

Cheers,

-- 
Pierre-Yves David