ocaml/Set up OCaml

Set up an OCaml and opam environment and add to PATH

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Scorecard Score: Scorecard 6–8scored Dec 22, 2024
Maintenance Recency: Activelast commit Jun 22, 2026
License: MIT

Pinned Snippet

workflow.ymlSHA-pinned

uses: ocaml/setup-ocaml@e32b06a3e831ff2fbc6f08cf35be2085e3918014 # v3.6.1

tags can be moved; commit SHAs can't. why a SHA?

Inputs

name	description	required	default
ocaml-compiler	The OCaml compiler packages to initialise. Accepts a semver version range (e.g. "5.3", "4.14.x") which is resolved to the latest matching version from opam-repository, or a full opam package name (e.g. "ocaml-variants.5.3.0+options,ocaml-option-flambda").	yes	—
opam-repositories	A YAML mapping of opam repository name/URL pairs to use. Repositories listed first take priority over later ones. The default is the official opam-repository. Set this to add custom or overlay repositories (e.g. "custom: https://my-repo.example.com").	no	default: git+https://github.com/ocaml/opam-repository.git
opam-pin	Automatically pin local opam packages (matched by "opam-local-packages") in the opam switch. Set to "false" to skip pinning.	no	true
opam-local-packages	A glob pattern matching the local .opam files to be pinned when "opam-pin" is enabled. The default "*.opam" matches all .opam files in the repository root.	no	*.opam
opam-disable-sandboxing	Disable the opam sandboxing feature. opam uses Bubblewrap on Linux and sandbox-exec on macOS. This is useful for self-hosted runners where the sandbox tool is not available. On Windows, sandboxing is always disabled regardless of this setting.	no	false
dune-cache	Enable Dune build caching via GitHub Actions cache. When enabled, the Dune cache directory is saved and restored between workflow runs to speed up incremental builds.	no	false
cache-prefix	The prefix used for all cache keys. Change this value to force a cache invalidation when the cache becomes corrupted or stale.	no	v3
windows-compiler	The C compiler toolchain used for building on Windows. Use "mingw" (default) for mingw-w64 (GCC), or "msvc" for the Microsoft Visual C compiler. MSVC requires Visual Studio on the runner (pre-installed on GitHub-hosted runners).	no	mingw
windows-environment	The Unix environment used for building on Windows. Use "cygwin" (default) for opam's internal Cygwin, or "msys2" to use the pre-installed MSYS2 on GitHub-hosted runners.	no	cygwin
allow-prerelease-opam	Allow the use of a pre-release version of opam. Set to "true" to opt in to pre-release builds when available. Has no effect when no pre-release version is available.	no	false
github-token	GitHub token used internally to query opam-repository for available compiler versions. The default token is sufficient for most use cases. DO NOT SET THIS unless you need to use a custom token.	no	${{ github.token }}

Outputs

no outputs