Guardrails / elixir

Elixir version is declared

elixir/version-declared@v1

The project declares the Elixir version it compiles against, and that version is no older than the configured floor.

Id	elixir/version-declared
Version	v1
Category	elixir
Default severity	warning
Interpreter	python3
Timeout	30 seconds
Violations tolerated	0
Collects	elixir

Collectors

This guardrail doesn't gather anything itself. It relies on the collectors below, which the CLI runs once per build before any check, and reads what they found from GUARDRAIL_FACTS. If a collector collects nothing, this guardrail is skipped, not failed.

Collector	Gathers	Inputs it is given
elixir	The Mix build in the project directory: the application it declares, the Elixir version it asks for, every application of an umbrella, the dependencies each manifest names with their environments and origins, and the lock file beside them. mix.exs is Elixir rather than a declaration, so what it declares conditionally is not seen and scanned says so.	projectDir

The inputs above are this guardrail's own inputs, passed straight through to the collector. Setting one in buildnote.json changes what is collected, and two guardrails configured the same way share a single collection.

Configuration

{
  "guardrails": {
      "failOn": "error",
      "checks": [
          {
              "use": "elixir/version-declared@v1",
              "severity": "warning",
              "with": {
                  "projectDir": ".",
                  "minVersion": "1.14"
              },
              "exemptions": []
          }
      ]
  }
}

Inputs

Input	Description	Default	Environment variable
projectDir	Directory holding the project, relative to the directory the CLI runs in.	.	GUARDRAIL_INPUT_PROJECTDIR
minVersion	Oldest Elixir version accepted. A declared version below this is a violation.	1.14	GUARDRAIL_INPUT_MINVERSION

How to fix

Declare the Elixir version in the project function of mix.exs, where the project already describes itself:

def project do
  [
    app: :widget,
    version: "1.2.3",
    elixir: "~> 1.16"
  ]
end

Without it, Mix compiles with whatever Elixir the runner has installed, so a macro or standard library difference between releases shows up in CI instead of on the laptop that introduced it.

More in elixir

• elixir/lockfile-committed. The project commits mix.lock, so fetching the same commit resolves the same packages and verifies them.
• elixir/no-git-dependencies. No dependency the project declares is fetched from a git repository.

All 3 elixir guardrails