Non-standard project initialization¶
Introduction¶
The purpose of this page is to collect information about issues that arise when users either have an existing cabal project or another nonstandard setup such as a private hackage database.
Using a Cabal File New users may be confused by the fact that you must add¶
dependencies to the package's cabal file, even in the case when you have
already listed the package in the stack.yaml
. In most cases, dependencies for
your package that are in the Stackage snapshot need only be added to the
cabal file. stack makes heavy use of Cabal the library under the hood. In
general, your stack packages should also end up being valid cabal-install
packages.
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/105
Passing Flags to Cabal¶
Any build command, bench
, install
, haddock
, test
, etc. takes a --flag
option which passes flags to cabal. Another way to do this is using the flags
field in a stack.yaml
, with the option to specify flags on a per package
basis.
As an example, in a stack.yaml
for multi-package project with packages foo
,
bar
, baz
:
flags:
foo:
release: true
bar:
default: true
baz:
manual: true
It is also possible to pass the same flag to multiple packages, i.e. stack
build --flag *:necessary
Currently one needs to list all of your modules that interpret flags in the
other-modules
section of a cabal file. cabal-install
has a different
behavior currently and doesn't require that the modules be listed. This may
change in a future release.
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/191
- https://github.com/commercialhaskell/stack/issues/417
- https://github.com/commercialhaskell/stack/issues/335
- https://github.com/commercialhaskell/stack/issues/301
- https://github.com/commercialhaskell/stack/issues/365
- https://github.com/commercialhaskell/stack/issues/105
Selecting a Resolver¶
stack init
or stack new
will try to default to the current Haskell LTS
present on https://www.stackage.org/snapshots
if no snapshot has been
previously used locally, and to the latest LTS snapshot locally used for a
build otherwise. Using an incorrect resolver can cause a build to fail if the
version of GHC it requires is not present.
In order to override the resolver entry at project initialization one can pass
--prefer-lts
or --prefer-nightly
. These options will choose the latest LTS
or nightly versions locally used. Alternatively the --resolver
option can be
used with the name of any snapshots on Stackage, or with lts
or nightly
to
select the latest versions, disregarding previously used ones. This is not the
default so as to avoid unnecessary recompilation time.
:TODO: Document --solver
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/468
- https://github.com/commercialhaskell/stack/issues/464
Using git Repositories¶
stack has support for packages that reside in remote git locations.
Example:
packages:
- '.'
- location:
git: https://github.com/kolmodin/binary
commit: 8debedd3fcb6525ac0d7de2dd49217dce2abc0d9
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/254
- https://github.com/commercialhaskell/stack/issues/199
Private Hackage¶
Working with a private Hackage is currently supported in certain situations.
There exist special entries in stack.yaml
that may help you. In a
stack.yaml
file, it is possible to add lines for packages in your database
referencing the sdist locations via an http
entry, or to use a Hackage
entry.
The recommended stack workflow is to use git submodules instead of a private
Hackage. Either by using git submodules and listing the directories in the
packages section of stack.yaml
, or by adding the private dependencies as git
URIs with a commit SHA to the stack.yaml
. This has the large benefit of
eliminating the need to manage a Hackage database and pointless version bumps.
For further information see YAML configuration
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/445
- https://github.com/commercialhaskell/stack/issues/565
Custom Snapshots¶
Currently WIP?
Issues Referenced¶
- https://github.com/commercialhaskell/stack/issues/111
- https://github.com/commercialhaskell/stack/issues/253
- https://github.com/commercialhaskell/stack/issues/137
Intra-package Targets¶
stack supports intra-package targets, similar to cabal build COMPONENTS
for
situations when you don't want to build every target inside your package.
Example:
stack build stack:lib:stack
stack test stack:test:stack-integration-test
Note: this does require prefixing the component name with the package name.
Issues referenced¶
- https://github.com/commercialhaskell/stack/issues/201