[Haskell-cafe] Cabal: other-modules necessary?

[Tom Ellis]

On Fri, Sep 16, 2022 at 10:47:47AM +0200, Volker Wysk wrote:
> The cabal user guide says (in section 6.2.12): "Every module in the package
> must be listed in one of other-modules, library:exposed-modules or
> executable:main-is fields."
> 
> However, I only get a warning message, when I comment out the other-modules
> field in my .cabal file. The program compiles. This is the message:
> 
> <no location info>: warning: [-Wmissing-home-modules]
>     These modules are needed for compilation but not listed in your .cabal 
>     file's other-modules: 
>         Hsskripte Sicherung SicherungAktionen Text Wahl Zeit
> 
> Is it really necessary to specify all the imported modules? If so, why does
> the program compile? Can that warning message be turned off?

In response to all the sibling replies at once, is there a good reason
for this behaviour?  Succeeding but then failing later with obscure
errors (once the original warning message is nowhere to be seen) seems
like the worst of all worlds.  Suppose cabal errored here and failed
to proceed.  What would be the downside of that (besides backward
incompatibility)?

Tom