[Scons-users] How to force a re-building of a cached file using the env.CacheDir() feature.

[Mats Wichmann]

On 1/18/23 12:33, Don Baldwin wrote:
> Hi,
> 
> We’re looking into using the SCons target-caching feature (using the 
> env.CacheDir() method), and there is a question of how to force a 
> re-caching of a particular file.  Is there a way to do this?

--cache-force, basically.  There's not any particular granularity to 
it... I don't think you can give a limited list of targets (one or more) 
and have only those be updated.

there's also an old issue with a patch which separates --cache-force and 
--cache-populate (which are currently synonyms) so that they don't 
behave exactly the same - though the proposed new behavior of of 
--cache-populate is rather the opposite of what you're looking for, it 
doesn't update any existing cached files (#1908).

> I looked into trying to find out the md5 value of a file, and then 
> deleting the cached file directly, and I’m running the ‘sconsign’ tool 
> on the .sconsign.dblite file with the -c option to get the csig value, 
> which I think is the same thing as the md5, but those values don’t seem 
> to match any of the filenames stored in the cache.

turns out the "build signature" (bsig) is what is used to generate the 
cache file name, not the content signature.