haskell-actions/setup
April 8, 2026 ยท View on GitHub
This action sets up a Haskell environment for use in actions by:
- if requested, installing a version of ghc and cabal and adding them to
PATH, - if requested, installing a version of Stack and adding it to the
PATH, - outputting of
ghc-version/exe/path,cabal-version/exe/path,stack-version/exe/path,stack-rootandcabal-store(for the requested components).
The GitHub runners come with pre-installed versions of GHC and Cabal.
Those will be used whenever possible.
For all other versions, this action utilizes
ghcup, and
chocolatey.
Usage
See action.yml and docs/examples.md.
Inputs
| Name | Description | Type | Default |
|---|---|---|---|
ghc-version | GHC version to use, e.g. 9.2 or 9.2.5. | string | latest |
cabal-version | Cabal version to use, e.g. 3.6. | string | latest |
stack-version | Stack version to use, e.g. latest. Stack will only be installed if enable-stack is set. | string | latest |
enable-stack | If set, will setup Stack. | "boolean" | false/unset |
stack-no-global | If set, enable-stack must be set. Prevents installing GHC and Cabal globally. | "boolean" | false/unset |
stack-setup-ghc | If set, enable-stack must be set. Runs stack setup to install the specified GHC. (Note: setting this does not imply stack-no-global.) | "boolean" | false/unset |
disable-matcher | If set, disables match messages from GHC as GitHub CI annotations. | "boolean" | false/unset |
cabal-update | If set to false, skip cabal update step. | boolean | true |
ghcup-release-channel | If set, add a release channel to ghcup. | URL | none |
Note: "boolean" types are set/unset, not true/false.
That is, setting any "boolean" to a value other than the empty string ("") will be considered true/set.
However, to avoid confusion and for forward compatibility, it is still recommended to only use value true to set a "boolean" flag.
In contrast, a proper boolean input like cabal-update only accepts values true and false.
Outputs
The action outputs parameters for the components it installed.
E.g. if ghc-version: 8.10 is requested, the action will output ghc-version: 8.10.7 if installation succeeded,
and ghc-exe and ghc-path will be set accordingly.
(Details on version resolution see next section.)
| Name | Description | Type |
|---|---|---|
ghc-version | The resolved version of ghc | string |
cabal-version | The resolved version of cabal | string |
stack-version | The resolved version of stack | string |
ghc-exe | The path of the ghc executable | string |
cabal-exe | The path of the cabal executable | string |
stack-exe | The path of the stack executable | string |
ghc-path | The path of the ghc executable directory | string |
cabal-path | The path of the cabal executable directory | string |
stack-path | The path of the stack executable directory | string |
cabal-store | The path to the cabal store | string |
stack-root | The path to the stack root (equal to the STACK_ROOT environment variable if it is set; otherwise an OS-specific default) | string |
Version Support
This action is conscious about the tool versions specified in versions.json.
This list is replicated (hopefully correctly) below.
Versions specified by the inputs, e.g. ghc-version, are resolved against this list,
by taking the first entry from the list if latest is requested,
or the first entry that matches exactly,
or otherwise the first entry that is a (string-)extension of the requested version extended by a ..
E.g., 8.10 will be resolved to 8.10.7, and so will 8.
GHC:
latest-nightly(requires the resp.ghcup-release-channel, e.g.https://ghc.gitlab.haskell.org/ghcup-metadata/ghcup-nightlies-0.0.7.yaml)latest(default)9.14.19.149.12.49.129.12.29.12.19.10.39.109.10.29.10.19.8.49.89.8.29.8.19.6.79.69.6.69.6.59.6.49.6.39.6.29.6.19.4.89.49.4.79.4.69.4.59.4.49.4.39.4.29.4.19.2.89.29.2.79.2.69.2.59.2.49.2.39.2.29.2.19.0.29.09.0.18.10.78.108.10.68.10.58.10.48.10.38.10.28.10.18.8.48.88.8.38.8.28.8.18.6.58.68.6.48.6.38.6.28.6.18.4.48.48.4.38.4.28.4.18.2.28.28.0.28.0
Suggestion: Try to support at least the three latest major versions of GHC.
Cabal:
head(the cabal-head release of the most recent build of themasterbranch)latest(default, recommended)3.16.1.03.163.16.0.03.14.2.03.143.14.1.13.14.1.03.12.1.03.123.10.3.03.103.10.2.13.10.2.0
Older versions of cabal are not supported due to vulnerability HSEC-2023-0015.
Recommendation: Use the latest available version if possible.
Stack: (with enable-stack: true)
latest(default, recommended)3.9.33.93.9.13.7.13.73.5.13.53.3.13.33.1.13.12.15.72.152.15.52.15.32.15.12.13.12.132.11.12.112.9.32.92.9.12.7.52.72.7.32.7.12.5.12.52.3.32.32.3.12.1.32.12.1.11.9.3.11.91.9.1.11.7.11.71.6.51.61.6.3.11.6.1.11.5.11.51.5.01.4.01.41.3.21.31.3.01.2.01.2
Recommendation: Use the latest available version if possible.
Beyond the officially supported listed versions above, you can request any precise version of GHC, Cabal, and Stack. The action will forward the request to the install methods (apt, ghcup, choco), and installation might succeed.
Note however that Chocolatey's version numbers might differ from the official ones, please consult their pages for GHC and Cabal.
License
The scripts and documentation in this project are released under the MIT License.
Contributions
Contributions are welcome! See the Contributor's Guide.