Stack work directories are directories within a local project or package
directory in which Stack stores files created during the build process. Stack
can be used without an understanding of the content of those directories. In
particular, the stack exec
command sets up an
environment where relevant subdirectories of the project Stack work directory
are on the PATH.
By default, Stack work directories are named .stack-work
. The name can be
overidden by:
- the use of the
STACK_WORK
environment variable; - the
work-dir
non-project specific configuration option; or - the
--work-dir
command line option.
Given the location of Stack work directories, the name of the work directories must be a relative path to a directory.
If the work directory does not already exist, it will be created by the
stack build
command as a subdirectory of each
project package directory and, if different, the project directory.
The Stack work directory for a project package will contain a dist
directory.
This directory will contain a path to a directory containing:
- a
build
directory; - a
package.conf.inplace
directory; - a
stack-build-caches
directory; - a
build-lock
file; - a
setup-config
file; - a
stack-cabal-mod
file. This file is used by Stack only for its modification time; - a
stack-project-root
file. This file contains an absolute path to the project root directory; and - a
stack-setup-config-mod
file. This file is used by Stack only for its modification time.
The directory, relative to the project package directory or the project
directory, is the one reported by
stack path --dist-dir
.
=== "Unix-like"
On Unix-like operating systems, the path to the directory is a directory
named after the platform (including Stack's classification of variants of
Linux distributions) followed by a directory named after the GHC version.
=== "Windows"
On Windows, the path to the directory is an eight-character hash of the
path that applies on Unix-like operating systems.
The Stack work directory for a project will contain a install
directory.
This directory will contain a path to a directory containing:
- a
bin
directory, containing built executable files; - a
doc
directory, containing a directory for each project package. This is the directory reported bystack path --local-doc-root
; - if the
stack hpc
command is used, ahpc
directory. This is the directory reported bystack path --local-hpc-root
; - a
lib
directory, containing a directory named after the platform and the GHC version and, within that, a directory for each project package; - a
pkgdb
directory. This is the directory reported bystack path --local-pkg-db
; - a
stack.sqlite3
file; and - a
stack.sqlite3.pantry-write-lock
file.
The directory is the one reported by
stack path --local-install-root
.
=== "Unix-like"
On Unix-like operating systems, the path to the directory is a directory
named after the platform (including Stack's classification of variants of
Linux distributions) followed by a directory named after a SHA 256 hash
(see further below) followed by a directory named after the version number
of GHC.
The SHA 256 hash is a hash of the following information:
* the path to the specified compiler;
* the information about the compiler provided by `ghc --info`;
* the options that Stack passes to GHC for package that is not a project
package; and
* information about the immutable dependencies: their location, whether or
not Haddock documentation is to be built, their flags, their GHC options,
and their Cabal configuration options.
The options that Stack passes to GHC for a package that is not a project
package depend on:
* the specification of
[profiling](../commands/build_command.md#flags-affecting-ghcs-behaviour);
* the specification of
[stripping](../commands//build_command.md#flags-affecting-ghcs-behaviour);
and
* if
[`apply-ghc-options: everything`](../configure/yaml/non-project.md#apply-ghc-options)
is specified, any GHC command line options specified on the command line.
!!! note
As a consequence, the path reported by the following commands will
differ (and similarly for the paths established by the
[`stack exec`](../commands/exec_command.md) command):
~~~text
stack path --local-install-root
stack --profile path --local-install-root
stack --no-strip path --local-install-root
stack --profile --no-strip path --local-install-root
~~~
=== "Windows"
On Windows, the path to the directory is an eight-character hash of the
path that applies on Unix-like operating systems.
Following a stack ghci
or stack repl
command, the Stack work directory for
a project will contain a ghci
directory. This directory will contain paths to
cabal_macos.h
files that are generated automatically by Cabal.
!!! note
Haskell Language Server makes use of the `stack ghci` command to obtain
information.
If the stack hoogle
command is used, the
Stack work directory for a project will contain a hoogle
directory. This
directory will contain a directory being the one reported by
stack path --local-hoogle-root
. The naming of
the path to the directory is same as for the path to the directory in the
install
directory.