[Haskell-beginners] Stack minimal dependency specification, or dependency tree output

[Josh Barney]

> On Feb 24, 2016, at 5:10 PM, Lyndon Maydwell <maydwell at gmail.com> wrote:
> 
> Hi Mark,
> 
> 
> That would be great, and I have tried that, but there is one issue that caused me to take the current approach instead.
> 
> The issue is that every change to
> 
> * Setup.hs
> * simple-app.cabal
> * stack.yaml
> 
> will cause the docker to consider the copy statement
> 
> > COPY LICENSE Setup.hs simple-app.cabal stack.yaml /app/
> 
> as a fresh checkpoint, and make the cache unusable. Since I've frequently changing stack.yaml, and app.cabal, this won't help me much.
> 
> Not sure if there's a way around that with this method.
> 
> Let me know if I've overlooked something with your approach!
> 
> 
>  - Lyndon
>> 

I have found that it works well to use a dummy file that does not change in order to set up a cache. You can then copy over the real file; preserving the cached docker layer.

Josh