be able to specify default values for system-ghc and resolver

[erantapaa]

Is there a way to default the value of system-ghc and resolver when creating a new stack.yaml?

I've tried adding them to my ~/.stack/global/stack.yaml file, but it doesn't seem to have any effect when using stack new.

Btw, I think defaulting system-ghc: false would be a good idea, especially for beginners if they have a corrupted ghc package db.

[borsboom]

In general, see the stack.yaml documentation for information about which options can go where.

In particular, since system-ghc is a non-project option, you can set its default in ~/.stack/stack.yaml. That file is always loaded before the project's stack.yaml (which can then override it).

There is no way to set the default resolver for stack new. However, it will tend to prefer a snapshot that you're already using (it uses the same algorithm as stack init)

The ~/.stack/global/stack.yaml file is only used as a "pseudo-project" for when you're performing operations outside a real project. Values in that file are not used in other cases.

Btw, I think defaulting system-ghc: false would be a good idea, especially for beginners if they have a corrupted ghc package db.

Do you think this is common? stack only uses the global GHC package database, not the user package database. That means a user would have had to be using sudo cabal install --global in order to mess up the global database. That seems like something they'd have to be pretty deliberate about.

[erantapaa]

Thanks for the reply!

Re the default value of system-ghc... I have a simple project which will not build unless I use system-ghc: false. If you want to help me debug the problem I can give you more details.

[snoyberg]

There is no way to set the default resolver for stack new.

Actually, the --resolver flag works for this, e.g.:

stack new foo simple --resolver lts-3.4

[borsboom]

Actually, the --resolver flag works for this,

Er, I meant no way to set it in a configuration file, but I should have been more specific. In general, we're pushing to make more command-line options settable in the config file, but I have my doubts as to whether this one should be. Stack new/init need to use some logic to determine the right resolver for the particular template or project, which means forcing a default is as likely to cause problems as it is to be helpful.

I have a simple project which will not build unless I use system-ghc: false

Have you done anything weird, such as perhaps installing multiple versions of a package in the global package database (Cabal and bytestring seem especially prone to this)? That should only happen if you explicitly use cabal --global, though. You can check that using ghc-pkg list --global. If so, I'd say re-install your system GHC with a fresh global package database. If things aren't working with a "fresh" system GHC, though, we should dig into that some more.

[snoyberg]

Closing due to lack of feedback. Issue #115 may be relevant.