Linter Rule: Require the framework option

Rule: herb-config-framework-option

Description

Reports templates in a project that doesn't set framework in its .herb.yml. The rule stays quiet as soon as framework is set, whichever value it is set to.

When a template shows what it is rendered by, the offense says so and suggests that value. Otherwise it lists the values to choose from.

Rationale

Herb tailors itself to the framework option. It decides what Herb may assume about a template, which rules apply, and which optimizations it can take. Without it Herb falls back to ruby and treats every template as plain ERB, which is the most conservative behavior it has.

The option is a project-level setting, and the CLI warns about it once per run, but that warning never reaches an editor. This rule brings it to where templates are actually written.

Two signals tell Herb the project is likely Action View, and both only shape the message:

• a strict locals declaration, which only Action View reads
• a call to a helper whose name is unmistakably Action View, so link_to and image_tag count while render, params, and t don't

Neither is a requirement for the offense. A template with no Ruby in it at all still reports, because the option is still missing.

The rule reports once per file, on the first line, and a CLI run collapses those down to a single offense since one missing config key doesn't need one report per template.

Examples

✅ Good

Any value silences the rule, including the ruby default when that is what the project means:

.herb.yml

framework: actionview

.herb.yml

framework: ruby

🚫 Bad

Without the option, every template reports:

<div class="card">
  <h1>Hello</h1>
</div>

Templates carrying an Action View signal get that value suggested:

<%= image_tag "logo.png", alt: "Logo" %>

<%# locals: (title:, subtitle: nil) %>
Strict local `subtitle` is never used in this partial. Callers can pass `subtitle:` for a value the template never renders. Remove it from the `locals:` declaration and from the call sites. (actionview-no-unused-strict-locals)
<h1><%= title %></h1>

Configuration

Set the framework in your .herb.yml to resolve the offense:

.herb.yml

framework: actionview # Options: ruby (default), actionview, hanami, sinatra

Or disable the rule if you prefer to keep the option unset:

.herb.yml

linter:
  rules:
    herb-config-framework-option:
      enabled: false

References

• Herb Configuration: Framework Configuration
• Action View Helpers