Use build.zig.zon as idiomatic version file for Zig

[kytta]

build.zig.zon are manifest files used in build.zig scripts, which in turn are used to build Zig projects. They contain meta information about the project: name, versions, and optionally minimum_zig_version.

I think it would be nice if mise would parse build.zig.zon, find minimum_zig_version and use it as idiomatic version file to download the needed Zig version.

Note: This has similar connotations to go.mod:

because it declares only the minimum required Go version, mise resolves it to the latest matching patch (e.g. go 1.22 → latest 1.22.x).

minimum_zig_version requires full semver, so I think mise should just download whatever version specified in this field, even if it's not the newest one.

[jdx]

Going to pass on this one.

The line mise draws in these manifests isn't "is there a version string in the file" — it's whether the field declares the version this project is developed with or the minimum a consumer needs. We read packageManager/devEngines from package.json and ignore engines, for exactly that reason.

minimum_zig_version is the engines case: a compatibility floor, with no exact-pin counterpart in the file. And treating it as an exact pin (as suggested here) inverts what the field means — a project that declares minimum_zig_version = "0.13.0" is saying "0.13.0 or newer", so we'd pin every Zig project to the oldest release it still supports rather than the version it's actually developed against. Resolving it as a floor instead would just mean "latest Zig", which isn't useful either.

On the go.mod precedent quoted above: that was a mistake, and #12259 fixes it. mise reads go.mod only for the toolchain goX.Y.Z directive, which is an exact pin of the toolchain the module builds and tests with. The go X.Y minimum is no longer read at all.

.zig-version and mise.toml both express the actual intent directly, so use one of those.

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[kytta]

I see, that makes total sense, and happy to see go.mod being adjusted as well :)

[jdx]

Correction on the go.mod note above: removing the go X.Y fallback outright would be a breaking change, so #12259 deprecates it instead. It still resolves today and warns, and is removed in mise 2026.11.0. Same for CMakeLists.txt's cmake_minimum_required, which had the same problem.

The rule itself is unchanged, and is now written down in the docs: mise reads fields that state the version a project is built with, not fields that state a minimum a consumer needs.

AI-assisted — Tool: Claude Code; model: anthropic/claude-opus-5; version: unavailable.