Description

When mise install --system installs both go and a go: backend tool (e.g. go:github.com/protocolbuffers/txtpbfmt/cmd/txtpbfmt) in the same invocation, the go-backend tool fails with No such file or directory (os error 2). The go binary is successfully installed, but the go-backend subprocess can't find it via PATH.

This does not happen with regular (non-system) mise install, which correctly makes the go binary available to go-backend tools during the same invocation.

The failure is deterministic when go is not already installed in the system data dir. With --jobs 1, mise correctly sequences go before the go-backend tool, but the binary still isn't resolvable:

mise [email protected]                         ✓ installed        ← go installs successfully
mise go:...txtpbfmt@... [1/3] install
mise ERROR Failed to install go:...txtpbfmt@...:
  failed to execute command: go install -mod=readonly ...:
  No such file or directory (os error 2)                    ← can't find "go"

Reproduction

mise.toml:

[tools]
go = "1.26.2"
"go:github.com/protocolbuffers/txtpbfmt/cmd/txtpbfmt" = "a481f6a22f9426d6c2cc3d4be185b28d156886e4"

[settings]
experimental = true

# Use fresh data dirs so go is not pre-installed
export MISE_DATA_DIR=$(mktemp -d)
export MISE_SYSTEM_DATA_DIR=$(mktemp -d)
mise trust mise.toml

# Fails — even with --jobs 1
mise install --system --jobs 1
# No such file or directory (os error 2)

# Works fine without --system
unset MISE_SYSTEM_DATA_DIR
export MISE_DATA_DIR=$(mktemp -d)
mise trust mise.toml
mise install --jobs 1
# ✓ installed

Root cause

Verbose output shows mise knows where go is but the go-backend subprocess uses bare go:

DEBUG $ /tmp/mise-sys-*/installs/go/1.26.2/bin/go version     ← full path: works
DEBUG $ go install -mod=readonly ...                           ← bare "go": ENOENT
DEBUG [core:[email protected]] list_bin_paths: ["...installs/go/1.26.2/bin"]
DEBUG [core:[email protected]] exec_env: {"GOBIN": "...", "GOROOT": "..."}

In regular mode, mise adds the go install path to the subprocess PATH. In --system mode, it doesn't — the go-backend subprocess inherits the outer PATH which doesn't include the system install dir.

Workaround

Pre-install go in a separate invocation:

mise install --system go        # go binary now available
mise install --system            # go-backend tools succeed

Environment

• mise: tested on 2026.4.15 and 2026.4.28 (latest) — both affected
• OS: macOS 15.4.1 (arm64), also reproduced on Ubuntu (x86_64) in Docker
• go: 1.26.2