vfox-poetry: env_keys.lua causes silent 5+ minute hang in CI

[marcusrbrown]

Problem

The embedded vfox-poetry plugin's env_keys.lua hook silently hangs for 5+ minutes in CI when the pyproject tool option is set. Three separate env var approaches to disable the behavior all fail due to architectural issues.

Environment

• mise v2026.2.18 (vfox-poetry embedded plugin)
• GitHub Actions (Ubuntu latest)
• Python 3.13, Poetry latest

Reproduction

# mise.toml
[env]
_.python.venv = { path = ".venv", create = true }

[tools]
poetry = { version = "latest", pyproject = "{{ config_root }}/pyproject.toml" }
python = "3.13"

In CI (cold runner, no cached venv), the mise install step hangs silently at env_keys.lua for 5+ minutes before being killed by workflow timeouts.

Root cause analysis

Three distinct issues compound to make this impossible to work around via env vars:

1. MISE_POETRY_VENV_AUTO is opt-in only — no way to disable the hook

The env_keys.lua check only recognizes "1" or "true":

local venv_auto = os.getenv("MISE_POETRY_VENV_AUTO")
if venv_auto == "1" or venv_auto == "true" then
    -- Only checks if poetry.lock exists
end
-- Falls through to blocking code regardless of value

Setting MISE_POETRY_VENV_AUTO=false or =0 has no effect — the code falls through and runs the blocking poetry run true / poetry install unconditionally. The env var only gates a poetry.lock existence check, not the venv creation itself.

2. [env] section values are not available to plugin hooks

toolset_env.rs calls env_from_tools() (which invokes EnvKeys hooks) before config.env() (which applies [env] from mise.toml). So any MISE_POETRY_* env vars set in [env] never reach os.getenv() in the Lua VM:

# These values are NEVER visible to the hook:
[env]
MISE_POETRY_AUTO_INSTALL = "false"
MISE_POETRY_VENV_AUTO = "false"

3. Blocking os.execute() with no output

The hook uses os.execute() and io.popen() with stderr redirected to /dev/null:

os.execute("cd '" .. pyproject_dir .. "' && ... poetry run true 2>/dev/null")
os.execute("cd '" .. pyproject_dir .. "' && ... poetry install 2>&1")

In CI (cold runner, no cached venv), poetry run true creates a virtualenv and poetry install installs all dependencies. Both run silently with no progress output, causing a 5+ minute hang with no indication of what is happening.

Workaround

Remove the pyproject tool option entirely. The hook returns early at line 43-46 when pyproject is not set. Use _.python.venv for venv creation and explicit poetry install in CI.

[tools]
poetry = "latest"  # no pyproject option

Suggested fixes

1. Add opt-out support: Check MISE_POETRY_VENV_AUTO != "0" and != "false" to allow disabling. Or better: check CI env var and skip the hook entirely in CI environments.

2. Stream output instead of suppressing it: Remove 2>/dev/null and 2>&1 redirections so users can see what is happening during long operations.

3. Apply [env] before hooks: If [env] values are intended to control plugin behavior (which the naming MISE_POETRY_* implies), they need to be in the process environment before EnvKeys hooks execute.

4. Add --skip-hooks flag: Allow mise install --skip-hooks or a setting like disable_hooks = ["poetry"] for CI environments.

Related

• jdx/mise#6703 — "Is it possible to disable postinstall hooks in a CI environment?"
• mise-plugins/vfox-poetry#2 — Plugin fails with missing python3
• mise-plugins/vfox-poetry#3 — Installation fails with precompiled Python