# YAML Configuration This page is intended to fully document all configuration options available in the stack.yaml file. Note that this page is likely to be both *incomplete* and sometimes *inaccurate*. If you see such cases, please update the page, and if you're not sure how, open an issue labeled "question". The stack.yaml configuration options break down into [project-specific](#project-specific-config) options in: - `/stack.yaml` and [non-project-specific](#non-project-specific-config) options in: - `/etc/stack/config.yaml` -- for system global non-project default options - `~/.stack/config.yaml` -- for user non-project default options - The project file itself may also contain non-project specific options *Note:* When stack is invoked outside a stack project it will source project specific options from `~/.stack/global-project/stack.yaml`. When stack is invoked inside a stack project, only options from `/stack.yaml` are used, and `~/.stack/global-project/stack.yaml` is ignored. *Note 2:* A common source of confusion is the distinction between configuration in a `stack.yaml` file versus a cabal file. If you're trying to understand this breakdown, see [stack vs cabal config](stack_yaml_vs_cabal_package_file.md). ## Project-specific config Project-specific options are only valid in the `stack.yaml` file local to a project, not in the user or global config files. > Note: We define **project** to mean a directory that contains a `stack.yaml` > file, which specifies how to build a set of packages. We define **package** to > be a package with a `.cabal` file or Hpack `package.yaml` file. In your project-specific options, you specify both **which local packages** to build and **which dependencies to use** when building these packages. Unlike the user's local packages, these dependencies aren't built by default. They only get built when needed. Shadowing semantics, described [here](https://docs.haskellstack.org/en/v1.5.1/architecture/#shadowing), are applied to your configuration. So, if you add a package to your `packages` list, it will be used even if you're using a snapshot that specifies a particular version. Similarly, `extra-deps` will shadow the version specified in the resolver. ### resolver > Note: Starting with **Stack 2.0**, `snapshot` is accepted as a synonym for `resolver`. Only one of these fields is permitted, not both. Specifies which snapshot is to be used for this project. A snapshot defines a GHC version, a number of packages available for installation, and various settings like build flags. It is called a resolver since a snapshot states how dependencies are resolved. There are currently four resolver types: * LTS Haskell snapshots, e.g. `resolver: lts-2.14` * Stackage Nightly snapshot, e.g. `resolver: nightly-2015-06-16` * No snapshot, just use packages shipped with the compiler * For GHC this looks like `resolver: ghc-7.10.2` * Custom snapshot, via a URL or relative file path. (See [pantry docs](pantry.md) for more information.) Each of these resolvers will also determine what constraints are placed on the compiler version. See the [compiler-check](#compiler-check) option for some additional control over compiler version. Since Stack 1.11, the resolver field corresponds to a Pantry snapshot location. See [the docs on pantry](pantry.md) for more information. ### packages _NOTE_ Beginning with Stack 1.11, Stack has moved over to Pantry for managing extra-deps, and has removed some legacy syntax for specifying dependencies in `packages`. See some conversion notes below. A list of packages that are part of your local project. These are specified via paths to local directories. The paths are considered relative to the directory containing the `stack.yaml` file. For example, if your `stack.yaml` is located at `/foo/bar/stack.yaml`, and you have: ```yaml packages: - hello - there/world ``` Your configuration means "I have packages in `/foo/bar/hello` and `/foo/bar/there/world`. If these packages should be treated as dependencies instead, specify them in `extra-deps`, described below. The `packages` field is _optional_. If omitted, it is treated as: ```yaml packages: - . ``` Each package directory specified must have a valid cabal file or hpack `package.yaml` file present. Note that the subdirectories of the directory are not searched for cabal files. Subdirectories will have to be specified as independent items in the list of packages. Meaning that your project has exactly one package, and it is located in the current directory. Project packages are different from snapshot dependencies (via `resolver`) and extra dependencies (via `extra-deps`) in multiple ways, e.g.: * Project packages will be built by default with a `stack build` without specific targets. Dependencies will only be built if they are depended upon. * Test suites and benchmarks may be run for project packages. They are never run for extra dependencies. __Legacy syntax__ Prior to Stack 1.11, it was possible to specify dependencies in your `packages` configuration value as well. This support has been removed to simplify the file format. Instead, these values should be moved to `extra-deps`. As a concrete example, you would convert: ```yaml packages: - . - location: git: https://github.com/bitemyapp/esqueleto.git commit: 08c9b4cdf977d5bcd1baba046a007940c1940758 extra-dep: true - location: git: https://github.com/yesodweb/wai.git commit: 6bf765e000c6fd14e09ebdea6c4c5b1510ff5376 subdirs: - wai-extra extra-dep: true extra-deps: - streaming-commons-0.2.0.0 - time-1.9.1 - yesod-colonnade-1.3.0.1 - yesod-elements-1.1 ``` into ```yaml packages: - . extra-deps: - streaming-commons-0.2.0.0 - time-1.9.1 - yesod-colonnade-1.3.0.1 - yesod-elements-1.1 - git: https://github.com/bitemyapp/esqueleto.git commit: 08c9b4cdf977d5bcd1baba046a007940c1940758 - git: https://github.com/yesodweb/wai.git commit: 6bf765e000c6fd14e09ebdea6c4c5b1510ff5376 subdirs: - wai-extra ``` And, in fact, the `packages` value could be left off entirely since it's using the default value. ### extra-deps This field allows you to specify extra dependencies on top of what is defined in your snapshot (specified in the `resolver` field mentioned above). These dependencies may either come from a local file path or a Pantry package location. For the local file path case, the same relative path rules as apply to `packages` apply. Pantry package locations allow you to include dependencies from three different kinds of sources: * Hackage * Archives (tarballs or zip files, either local or over HTTP(S)) * Git or Mercurial repositories Here's an example using all of the above: ```yaml extra-deps: - vendor/hashable - streaming-commons-0.2.0.0 - time-1.9.1 - yesod-colonnade-1.3.0.1 - yesod-elements-1.1 - git: https://github.com/bitemyapp/esqueleto.git commit: 08c9b4cdf977d5bcd1baba046a007940c1940758 - url: https://github.com/yesodweb/wai/archive/6bf765e000c6fd14e09ebdea6c4c5b1510ff5376.tar.gz subdirs: - wai-extra - github: snoyberg/conduit commit: 2e3e41de93821bcfe8ec6210aeca21be3f2087bf subdirs: - network-conduit-tls ``` If no `extra-deps` value is provided, it defaults to an empty list, e.g.: ```yaml extra-deps: [] ``` For more information on the format for specifying dependencies, please see [the Pantry docs](pantry.md). ### flags Flags can be set for each package separately, e.g. ```yaml flags: package-name: flag-name: true ``` If a specified flag is different than the one specified for a snapshot package, then the snapshot package will automatically be promoted to be an extra-dep. ### drop-packages Packages which, when present in the snapshot specified in `resolver`, should not be included in our package. This can be used for a few different purposes, e.g.: * Ensure that packages you don't want used in your project cannot be used in a `package.yaml` file (e.g., for license reasons) * Prevent overriding of a global package like `Cabal`. For more information, see [stackage#4425](https://github.com/commercialhaskell/stackage/issues/4425) * When using a custom GHC build, avoid incompatible packages (see [this comment](https://github.com/commercialhaskell/stack/pull/4655#issuecomment-477954429)). ```yaml drop-packages: - Cabal - buggy-package - package-with-unacceptable-license ``` Since Stack 2.0 ### user-message A user-message is inserted by `stack init` when it omits packages or adds external dependencies. For example: ```yaml user-message: ! 'Warning: Some packages were found to be incompatible with the resolver and have been left commented out in the packages section. Warning: Specified resolver could not satisfy all dependencies. Some external packages have been added as dependencies. You can omit this message by removing it from stack.yaml ' ``` This messages is displayed every time the config is loaded by stack and serves as a reminder for the user to review the configuration and make any changes if needed. The user can delete this message if the generated configuration is acceptable. ### custom-preprocessor-extensions In order for stack to be aware of any custom preprocessors you are using, add their extensions here ```yaml custom-preprocessor-extensions: - erb ``` TODO: Add a simple example of how to use custom preprocessors. ## Non-project-specific config Non-project config options may go in the global config (`/etc/stack/config.yaml`) or the user config (`~/.stack/config.yaml`). ### docker See [Docker integration](docker_integration.md#configuration). ### nix (since 0.1.10.0) See [Nix integration](nix_integration.md#configuration). ### connection-count Integer indicating how many simultaneous downloads are allowed to happen Default: `8` ### hide-th-loading Strip out the "Loading ..." lines from GHC build output, produced when using Template Haskell Default: `true` ### local-bin-path Target directory for `stack install` and `stack build --copy-bins`. Default: `~/.local/bin` ### package-indices Since Stack 1.11, this field may only be used to specify a single package index, which must use the Hackage Security format. For the motivation for this change, please see [issue #4137](https://github.com/commercialhaskell/stack/issues/4137). Therefore, this field is most useful for providing an alternate Hackage mirror either for: * Bypassing a firewall * Faster download speeds The following is the default setting for this field: ```yaml package-indices: - download-prefix: https://hackage.haskell.org/ hackage-security: keyids: - 0a5c7ea47cd1b15f01f5f51a33adda7e655bc0f0b0615baa8e271f4c3351e21d - 1ea9ba32c526d1cc91ab5e5bd364ec5e9e8cb67179a471872f6e26f0ae773d42 - 280b10153a522681163658cb49f632cde3f38d768b736ddbc901d99a1a772833 - 2a96b1889dc221c17296fcc2bb34b908ca9734376f0f361660200935916ef201 - 2c6c3627bd6c982990239487f1abd02e08a02e6cf16edb105a8012d444d870c3 - 51f0161b906011b52c6613376b1ae937670da69322113a246a09f807c62f6921 - 772e9f4c7db33d251d5c6e357199c819e569d130857dc225549b40845ff0890d - aa315286e6ad281ad61182235533c41e806e5a787e0b6d1e7eef3f09d137d2e9 - fe331502606802feac15e514d9b9ea83fee8b6ffef71335479a2e68d84adc6b0 key-threshold: 3 # number of keys required # ignore expiration date, see https://github.com/commercialhaskell/stack/pull/4614 ignore-expiry: true ``` If you provide a replacement index which does not mirror Hackage, it is likely that you'll end up with significant breakage, such as most snapshots failing to work. Note: since Stack v2.1.3, `ignore-expiry` was changed to `true` by default. For more information on this change, see [issue #4928](https://github.com/commercialhaskell/stack/issues/4928). ### system-ghc Enables or disables using the GHC available on the PATH. (Make sure PATH is explicit, i.e., don't use ~.) Useful to enable if you want to save the time, bandwidth or storage space needed to setup an isolated GHC. Default is `false` unless the [Docker](docker_integration.md) or [Nix](nix_integration.md) integration is enabled. In a Nix-enabled configuration, stack is incompatible with `system-ghc: false`. ```yaml # Turn on system GHC system-ghc: true ``` ### install-ghc Whether or not to automatically install GHC when necessary. Since Stack 1.5.0, the default is `true`, which means Stack will not ask you before downloading and installing GHC. ### skip-ghc-check Should we skip the check to confirm that your system GHC version (on the PATH) matches what your project expects? Default is `false`. ### require-stack-version Require a version of stack within the specified range ([cabal-style](https://www.haskell.org/cabal/users-guide/developing-packages.html#build-information)) to be used for this project. Example: `require-stack-version: "== 0.1.*"` Default: `"-any"` ### arch/os Set the architecture and operating system for GHC, build directories, etc. Values are those recognized by Cabal, e.g.: arch: i386, x86_64 os: windows, linux You likely only ever want to change the arch value. This can also be set via the command line. ### extra-include-dirs/extra-lib-dirs A list of extra paths to be searched for header files and libraries, respectively. Paths should be absolute ```yaml extra-include-dirs: - /opt/foo/include extra-lib-dirs: - /opt/foo/lib ``` Since these are system-dependent absolute paths, it is recommended that you specify these in your `config.yaml` within the stack root (usually, `~/.stack` or, on Windows, `%LOCALAPPDATA%\Programs\stack`). If you control the build environment in your project's ``stack.yaml``, perhaps through docker or other means, then it may well make sense to include these there as well. ### with-gcc Specify a path to gcc explicitly, rather than relying on the normal path resolution. ```yaml with-gcc: /usr/local/bin/gcc-5 ``` ### with-hpack Use an Hpack executable, rather than using the bundled Hpack. ```yaml with-hpack: /usr/local/bin/hpack ``` ### compiler-check (Since 0.1.4) Specifies how the compiler version in the resolver is matched against concrete versions. Valid values: * `match-minor`: make sure that the first three components match, but allow patch-level differences. For example< 7.8.4.1 and 7.8.4.2 would both match 7.8.4. This is useful to allow for custom patch levels of a compiler. This is the default * `match-exact`: the entire version number must match precisely * `newer-minor`: the third component can be increased, e.g. if your resolver is `ghc-7.10.1`, then 7.10.2 will also be allowed. This was the default up through stack 0.1.3 ### compiler (Since 0.1.7) Overrides the compiler version in the resolver. Note that the `compiler-check` flag also applies to the version numbers. This uses the same syntax as compiler resolvers like `ghc-8.6.5`. This can be used to override the compiler for a Stackage snapshot, like this: ```yaml resolver: lts-14.20 compiler: ghc-8.6.4 compiler-check: match-exact ``` #### Building GHC from source (experimental) (Since 2.0) Stack supports building the GHC compiler from source. The version to build and to use is defined by a a Git commit ID and an Hadrian "flavour" (Hadrian is the build system of GHC) with the following syntax: ```yaml compiler: ghc-git-COMMIT-FLAVOUR ``` In the following example the commit ID is "5be7ad..." and the flavour is "quick": ```yaml compiler: ghc-git-5be7ad7861c8d39f60b7101fd8d8e816ff50353a-quick ``` By default the code is retrieved from the main GHC repository. If you want to select another repository, set the "compiler-repository" option: ```yaml compiler-repository: git://my/ghc/repository # default # compiler-repository: https://gitlab.haskell.org/ghc/ghc.git ``` Note that Stack doesn't check the compiler version when it uses a compiler built from source. Moreover it is assumed that the built compiler is recent enough as Stack doesn't enable any known workaround to make older compilers work. Building the compiler can take a very long time (more than one hour). Hint: for faster build times, use Hadrian flavours that disable documentation generation. #### Global packages The GHC compiler you build from sources may depend on unreleased versions of some global packages (e.g. Cabal). It may be an issue if a package you try to build with this compiler depends on such global packages because Stack may not be able to find versions of those packages (on Hackage, etc.) that are compatible with the compiler. The easiest way to deal with this issue is to drop the offending packages as follows. Instead of using the packages specified in the resolver, the global packages bundled with GHC will be used. ```yaml drop-packages: - Cabal - ... ``` Another way to deal with this issue is to add the relevant packages as `extra-deps` built from source. To avoid mismatching versions, you can use exactly the same commit id you used to build GHC as follows: ``` extra-deps: - git: https://gitlab.haskell.org/ghc/ghc.git commit: 5be7ad7861c8d39f60b7101fd8d8e816ff50353a subdirs: - libraries/Cabal/Cabal - libraries/... ``` #### Bootstrapping compiler Building GHC from source requires a working GHC (known as the bootstrap compiler). As we use a Stack based version of Hadrian (`hadrian/build-stack` in GHC sources), the bootstrap compiler is configured into `hadrian/stack.yaml` and fully managed by Stack. ### ghc-options (Since 0.1.4) Allows specifying per-package and global GHC options: ```yaml ghc-options: # All packages "$locals": -Wall "$targets": -Werror "$everything": -O2 some-package: -DSOME_CPP_FLAG ``` Since 1.6.0, setting a GHC options for a specific package will automatically promote it to a local package (much like setting a custom package flag). However, setting options via `$everything` on all flags will not do so (see [Github discussion](https://github.com/commercialhaskell/stack/issues/849#issuecomment-320892095) for reasoning). This can lead to unpredictable behavior by affecting your snapshot packages. The behavior of the `$locals`, `$targets`, and `$everything` special keys mirrors the behavior for the [`apply-ghc-options` setting](#apply-ghc-options), which affects command line parameters. NOTE: Prior to version 1.6.0, the `$locals`, `$targets`, and `$everything` keys were not supported. Instead, you could use `"*"` for the behavior represented now by `$everything`. It is highly recommended to switch to the new, more expressive, keys. ### apply-ghc-options (Since 0.1.6) Which packages do ghc-options on the command line get applied to? Before 0.1.6, the default value was `targets` ```yaml apply-ghc-options: locals # all local packages, the default # apply-ghc-options: targets # all local packages that are targets # apply-ghc-options: everything # applied even to snapshot and extra-deps ``` Note that `everything` is a slightly dangerous value, as it can break invariants about your snapshot database. ### rebuild-ghc-options (Since 0.1.6) Should we rebuild a package when its GHC options change? Before 0.1.6, this was a non-configurable true. However, in most cases, the flag is used to affect optimization levels and warning behavior, for which GHC itself doesn't actually recompile the modules anyway. Therefore, the new behavior is to not recompile on an options change, but this behavior can be changed back with the following: ```yaml rebuild-ghc-options: true ``` ### configure-options Options which are passed to the configure step of the Cabal build process. These can either be set by package name, or using the `$everything`, `$targets`, and `$locals` special keys. These special keys have the same meaning as in `ghc-options`. ```yaml configure-options: $everything: - --with-gcc - /some/path my-package: - --another-flag ``` (Since 2.0) ### ghc-variant (Since 0.1.5) Specify a variant binary distribution of GHC to use. Known values: * `standard`: This is the default, uses the standard GHC binary distribution * `integersimple`: Use a GHC bindist that uses [integer-simple instead of GMP](https://ghc.haskell.org/trac/ghc/wiki/ReplacingGMPNotes) * any other value: Use a custom GHC bindist. You should specify [setup-info](#setup-info) or [setup-info-locations](#setup-info-locations) so `stack setup` knows where to download it, or pass the `stack setup --ghc-bindist` argument on the command-line This option is incompatible with `system-ghc: true`. ### ghc-build (Since 1.3.0) Specify a specialized architecture bindist to use. Normally this is determined automatically, but you can override the autodetected value here. Possible arguments include `standard`, `gmp4`, `tinfo6`, and `nopie`. ### setup-info-locations (Since 2.3) Possible usages of this config are: 1. Using `stack` offline or behind a firewall 2. Extending the tools known to `stack` such as cutting-edge versions of `ghc` or builds for custom linux distributions. The `setup-info` dictionary specifies locations for installation of Haskell-related tooling - it maps `(Tool, Platform, Version)` to the location where it can be obtained, such as `(GHC, Windows64, 8.6.5)` to the url hosting the `*.tar.xz` for GHC's installation. By default, it's obtained from [stack-setup-2.yaml](https://github.com/commercialhaskell/stackage-content/raw/master/stack/stack-setup-2.yaml). The `setup-info` dictionary is constructed in the following order: 1. `setup-info` yaml configuration - inline config 2. `--setup-info-yaml` command line arguments - urls or paths, multiple locations may be specified. 3. `setup-info-locations` yaml configuration - urls or paths The first location which specifies the location of a tool `(Tool, Platform, Version)` takes precedence, so one can extend the default tools with a fallback to the default `setup-info` location: ```yaml setup-info-locations: - C:/stack-offline/my-stack-setup.yaml - relative/inside/my/project/setup-info.yaml - \\smbShare\stack\my-stack-setup.yaml - http://stack-mirror.com/stack-setup.yaml - https://github.com/commercialhaskell/stackage-content/raw/master/stack/stack-setup-2.yaml ``` The default `setup-info` location is included only if no locations in the `setup-info-locations` config or the `--setup-info-yaml` command line argument were specified. Thus the following will cause `stack setup` not to consult github for the `setup-info`: ```yaml setup-info-locations: - C:/stack-offline/my-stack-setup.yaml ``` ```yaml setup-info-locations: [] ``` Relative paths are resolved relative to the `stack.yaml` file - either in the local project or the global `stack.yaml` in the stack directory. Relative paths may also be used inside paths to tool installs - such as for ghc or 7z, which allows vendoring the tools inside a monorepo. For example: Directory structure: ``` - src/ - installs/ - my-stack-setup.yaml - 7z.exe - 7z.dll - ghc-8.2.2.tar.xz - stack.yaml ``` In the project's `stack.yaml`: ```yaml setup-info-locations: - installs/my-stack-setup.yaml ``` In `installs/my-stack-setup.yaml`: ```yaml sevenzexe-info: url: "installs/7z.exe" sevenzdll-info: url: "installs/7z.dll" ghc: windows64: 8.2.2: url: "installs/ghc-8.2.2.tar.xz" ``` ### setup-info (Since 0.1.5) Allows augmenting from where tools like GHC and msys2 (on Windows) are downloaded. Most useful for specifying locations of custom GHC binary distributions (for use with the [ghc-variant](#ghc-variant) option). The format of this field is the same as in the default [stack-setup-2.yaml](https://github.com/commercialhaskell/stackage-content/raw/master/stack/stack-setup-2.yaml): ```yaml setup-info: ghc: windows32-custom-foo: 7.10.2: url: "https://example.com/ghc-7.10.2-i386-unknown-mingw32-foo.tar.xz" ``` This configuration **adds** the specified setup info metadata to the default; Specifying this config **does not** prevent the default `stack-setup-2.yaml` from being consulted as a fallback. If you need to **replace** the default setup-info, add the following: ```yaml setup-info-locations: [] ``` ### pvp-bounds (Since 0.1.5) __NOTE__ As of Stack 1.6.0, this feature does not reliably work, due to issues with the Cabal library's printer. Stack will generate a warning when a lossy conversion occurs, in which case you may need to disable this setting. See [#3550](https://github.com/commercialhaskell/stack/issues/3550) for more information. When using the `sdist` and `upload` commands, this setting determines whether the cabal file's dependencies should be modified to reflect PVP lower and upper bounds. Values are `none` (unchanged), `upper` (add upper bounds), `lower` (add lower bounds), and both (and upper and lower bounds). The algorithm it follows is: * If an upper or lower bound already exists on a dependency, it's left alone * When adding a lower bound, we look at the current version specified by stack.yaml, and set it as the lower bound (e.g., `foo >= 1.2.3`) * When adding an upper bound, we require less than the next major version (e.g., `foo < 1.3`) ```yaml pvp-bounds: none ``` For more information, see [the announcement blog post](https://www.fpcomplete.com/blog/2015/09/stack-pvp). __NOTE__ Since Stack 1.5.0, each of the values listed above supports adding `-revision` to the end of each value, e.g. `pvp-bounds: both-revision`. This means that, when uploading to Hackage, Stack will first upload your tarball with an unmodified `.cabal` file, and then upload a cabal file revision with the PVP bounds added. This can be useful—especially combined with the [Stackage no-revisions feature](http://www.snoyman.com/blog/2017/04/stackages-no-revisions-field)—as a method to ensure PVP compliance without having to proactively fix bounds issues for Stackage maintenance. ### modify-code-page (Since 0.1.6) Modify the code page for UTF-8 output when running on Windows. Default behavior is to modify. ```yaml modify-code-page: false ``` ### allow-newer (Since 0.1.7) Ignore version bounds in .cabal files. Default is false. ```yaml allow-newer: true ``` Note that this also ignores lower bounds. The name "allow-newer" is chosen to match the commonly used cabal option. ### allow-different-user (Since 1.0.1) Allow users other than the owner of the stack root directory (typically `~/.stack`) to use the stack installation. The default is `false`. POSIX systems only. ```yaml allow-different-user: true ``` The intention of this option is to prevent file permission problems, for example as the result of a `stack` command executed under `sudo`. The option is automatically enabled when `stack` is re-spawned in a Docker process. ### build (Since 1.1.0) Allows setting build options which are usually specified on the CLI. Here are the settings with their defaults: ```yaml build: library-profiling: false executable-profiling: false copy-bins: false prefetch: false keep-going: false keep-tmp-files: false # NOTE: global usage of haddock can cause build failures when documentation is # incorrectly formatted. This could also affect scripts which use stack. haddock: false haddock-arguments: haddock-args: [] # Additional arguments passed to haddock, --haddock-arguments # haddock-args: # - "--css=/home/user/my-css" open-haddocks: false # --open haddock-deps: false # if unspecified, defaults to true if haddock is set haddock-internal: false # These are inadvisable to use in your global configuration, as they make the # stack build CLI behave quite differently. test: false test-arguments: rerun-tests: true # Rerun successful tests additional-args: [] # --test-arguments # additional-args: # - "--fail-fast" coverage: false no-run-tests: false bench: false benchmark-opts: benchmark-arguments: "" # benchmark-arguments: "--csv bench.csv" no-run-benchmarks: false force-dirty: false reconfigure: false cabal-verbose: false split-objs: false # Since 1.8. Starting with 2.0, the default is true interleaved-output: true # Since 1.10 ddump-dir: "" ``` The meanings of these settings correspond directly with the CLI flags of the same name. See the [build command docs](build_command.md) and the [users guide](GUIDE.md#the-build-command) for more info. ### dump-logs (Since 1.3.0) Control which log output from local non-dependency packages to print to the console. By default, Stack will only do this when building a single target package or if the log contains warnings, to avoid generating unnecessarily verbose output. ```yaml dump-logs: none # don't dump logs even if they contain warnings dump-logs: warning # default: dump logs that contain warnings dump-logs: all # dump all logs for local non-dependency packages ``` ### templates Templates used with `stack new` have a number of parameters that affect the generated code. These can be set for all new projects you create. The result of them can be observed in the generated LICENSE and cabal files. The value for all of these parameters must be strings. The parameters are: `author-email`, `author-name`, `category`, `copyright`, `year` and `github-username`. * _author-email_ - sets the `maintainer` property in cabal * _author-name_ - sets the `author` property in cabal and the name used in LICENSE * _category_ - sets the `category` property in cabal. This is used in Hackage. For examples of categories see [Packages by category](https://hackage.haskell.org/packages/). It makes sense for `category` to be set on a per project basis because it is uncommon for all projects a user creates to belong to the same category. The category can be set per project by passing `-p "category:value"` to the `stack new` command. * _copyright_ - sets the `copyright` property in cabal. It is typically the name of the holder of the copyright on the package and the year(s) from which copyright is claimed. For example: `Copyright (c) 2006-2007 Joe Bloggs` * _year_ - if `copyright` is not specified, `year` and `author-name` are used to generate the copyright property in cabal. If `year` is not specified, it defaults to the current year. * _github-username_ - used to generate `homepage` and `source-repository` in cabal. For instance `github-username: myusername` and `stack new my-project new-template` would result: ```yaml homepage: http://github.com/myusername/my-project#readme source-repository head type: git location: https://github.com/myusername/my-project ``` These properties can be set in `config.yaml` as follows: ```yaml templates: params: author-name: Your Name author-email: youremail@example.com category: Your Projects Category copyright: 'Copyright (c) 2021 Your Name' github-username: yourusername ``` Additionally, `stack new` can automatically initialize source control repositories in the directories it creates. Source control tools can be specified with the `scm-init` option. At the moment, only `git` is supported. ```yaml templates: scm-init: git ``` ### save-hackage-creds Controls whether, when using `stack upload`, the user's Hackage username and password are stored in a local file. Default: true. ```yaml save-hackage-creds: true ``` Since 1.5.0 ### hackage-base-url Sets the address of the Hackage server to upload the package to. Default is `https://hackage.haskell.org/`. ```yaml hackage-base-url: https://hackage.example.com/ ``` Since 1.9.1 ### ignore-revision-mismatch This flag was introduced in Stack 1.6, and removed in Stack 1.11 with the move to Pantry. You will receive a warning if this configuration value is set. ### urls Customize the URLs where `stack` looks for snapshot build plans. The default configuration is ```yaml urls: latest-snapshot: https://www.stackage.org/download/snapshots.json ``` ### jobs Specifies how many build tasks should be run in parallel. This can be overloaded on the commandline via `-jN`, for example `-j2`. The default is to use the number of processors reported by your CPU. One usage for this might be to avoid running out of memory by setting it to 1, like this: ```yaml jobs: 1 ``` ### work-dir Specifies relative path of work directory (default is `.stack-work`. This can also be specified by env var or cli flag, in particular, the earlier items in this list take precedence: 1. `--work-dir DIR` passed on the commandline 2. `work-dir` in stack.yaml 3. `STACK_WORK` environment variable Since 0.1.10.0 ### skip-msys Skips checking for and installing msys2 when stack is setting up the environment. This is only useful on Windows machines, and usually doesn't make sense in project configurations, just in `config.yaml`. Defaults to `false`, so if this is used, it only really makes sense to use it like this: ```yaml skip-msys: true ``` Since 0.1.2.0 ### concurrent-tests This option specifies whether test-suites should be executed concurrently with each-other. The default for this is true, since this is usually fine and it often means that tests can complete earlier. However, if some test-suites require exclusive access to some resource, or require a great deal of CPU or memory resources, then it makes sense to set this to `false` (the default is `true`). ```yaml concurrent-tests: false ``` Since 0.1.2.0 ### extra-path This option specifies additional directories to prepend to the PATH environment variable. These will be used when resolving the location of executables, and will also be visible in the `PATH` variable of processes run by stack. For example, to prepend `/path-to-some-dep/bin` to your PATH: ```yaml extra-path: - /path-to-some-dep/bin ``` One thing to note is that other paths added by stack - things like the project's bin dir and the compiler's bin dir - will take precedence over those specified here (the automatic paths get prepended). Since 0.1.4.0 ### local-programs-path This overrides the location of the programs directory, where tools like ghc and msys get installed. On most systems, this defaults to a folder called `programs` within the stack root directory. On Windows, if the `LOCALAPPDATA` environment variable exists, then it defaults to `%LOCALAPPDATA%\Programs\stack`, which follows Windows' conventions. __NOTE__: On Windows, if there is a space character in the `%LOCALAPPDATA%` path (which may be the case if the relevant user account name and its corresponding user profie path have a space) this may cause problems with building packages that make use of the GNU project's `autoconf` package and `configure` shell script files. That may be the case particularly if there is no corresponding short name ('8 dot 3' name) for the folder in the path with the space (which may be the case if '8 dot 3' names have been stripped or their creation not enabled by default). If there are problems building, it will be necessary to override the default location of stack's programs directory to specify an alternative path that does not contain space characters. Examples of packages on Hackage that make use of `configure` are `network` and `process`. Since 1.3.0 ### default-template This option specifies which template to use with `stack new`, when none is specified. The default is called `new-template`. The other templates are listed in [the stack-templates repo](https://github.com/commercialhaskell/stack-templates/). ### color This option specifies when to use color in output. The option is used as `color: `, where `` is 'always', 'never', or 'auto'. On Windows versions before Windows 10, for terminals that do not support color codes, the default is 'never'; color may work on terminals that support color codes. The color use can also be set at the command line using the equivalent `--color=` global option. Color use set at the command line takes precedence over that set in a yaml configuration file. (The British English spelling (colour) is also accepted. In yaml configuration files, the American spelling is the alternative that has priority.) ### stack-colors Stack uses styles to format some of its output. The default styles do not work well with every terminal theme. This option specifies stack's output styles, allowing new styles to replace the defaults. The option is used as `stack-colors: `, where `` is a colon-delimited sequence of key=value, 'key' is a style name and 'value' is a semicolon-delimited list of 'ANSI' SGR (Select Graphic Rendition) control codes (in decimal). Use the command `stack ls stack-colors --basic` to see the current sequence. The 'ANSI' standards refer to (1) standard ECMA-48 'Control Functions for Coded Character Sets' (5th edition, 1991); (2) extensions in ITU-T Recommendation (previously CCITT Recommendation) T.416 (03/93) 'Information Technology – Open Document Architecture (ODA) and Interchange Format: Character Content Architectures' (also published as ISO/IEC International Standard 8613-6); and (3) further extensions used by 'XTerm', a terminal emulator for the X Window System. The 'ANSI' SGR codes are described in a [Wikipedia article](http://en.wikipedia.org/wiki/ANSI_escape_code) and those codes supported on current versions of Windows in [Microsoft's documentation](https://docs.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences). For example, users of the popular [Solarized Dark](https://ethanschoonover.com/solarized/) terminal theme might wish to set the styles as follows: ```yaml stack-colors: error=31:good=32:shell=35:dir=34:recommendation=32:target=95:module=35:package-component=95:secondary=92:highlight=32 ``` The styles can also be set at the command line using the equivalent `--stack-colors=` global option. Styles set at the command line take precedence over those set in a yaml configuration file. (In respect of styles used in verbose output, some of that output occurs before the configuration file is processed.) (The British English spelling (colour) is also accepted. In yaml configuration files, the American spelling is the alternative that has priority.) ### hide-source-paths Stack will use the `-fhide-source-paths` option by default for GHC >= 8.2, unless this option is set to `false` as in the following example: ```yaml hide-source-paths: false ``` Build output when enabled: ``` ... [1 of 2] Compiling Lib [2 of 2] Compiling Paths_test_pr ... ``` Build output when disabled: ``` ... [1 of 2] Compiling Lib ( src/Lib.hs, .stack-work/dist/x86_64-linux-tinfo6/Cabal-2.4.0.1/build/Lib.o ) ... ``` ### recommend-stack-upgrade When Stack notices that a new version of Stack is available, should it notify the user? ```yaml recommend-stack-upgrade: true ``` Since 2.0 ### stack-developer-mode Turns on a mode where some messages are printed at WARN level instead of DEBUG level, especially useful for developers of Stack itself. For official distributed binaries, this is set to `false` by default. When you build from source, it is set to `true` by default. ```yaml stack-developer-mode: false ``` Since 2.3.3 ### snapshot-location-base Sets the base location of LTS Haskell/Stackage Nightly snapshots. Default is https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/ (as set in the `pantry` library). For example: ```yaml snapshot-location-base: https://example.com/snapshots/location/ ``` has the following effect: * `lts-X.Y` expands to `https://example.com/snapshots/location/lts/X/Y.yaml` * `nightly-YYYY-MM-DD` expands to `https://example.com/snapshots/location/nightly/YYYY/M/D.yaml` This field is convenient in setups that restrict access to GitHub, for instance closed corporate setups. In this setting, it is common for the development environment to have general access to the internet, but not for testing/building environments. To avoid the firewall, one can run a local snapshots mirror and then use a custom `snapshot-location-base` in the closed environments only. Since 2.5.0