Extension points

Every feature declares which parts of itself are safe to override. This is the [tool.splent.contract.extensible] section in pyproject.toml.

Table of contents

• What it means
• Example: auth
• Categories
• Auto-inference
• See also

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What it means

“These parts of my feature can be overridden or extended by a refinement feature.” If a refiner tries to override something not listed here, the framework raises an error at startup.

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Example: auth

[tool.splent.contract.extensible]
services  = ["AuthenticationService"]
templates = ["auth/login_form.html", "auth/signup_form.html"]
models    = ["User"]
hooks     = ["layout.anonymous_sidebar", "layout.authenticated_sidebar",
             "layout.navbar.anonymous", "layout.navbar.authenticated"]
routes    = true

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Categories

Category	Meaning
services	Service classes replaceable via the service locator
templates	Jinja templates overridable by a refiner’s blueprint
models	SQLAlchemy models extendable with mixin columns/methods
hooks	Template hooks that can be replaced (not just appended to)
routes	If true, refiners can add new routes to this feature’s blueprint

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Auto-inference

feature:contract --write and feature:release auto-generate the extensible section from source code:

• services, models — from class definitions in services.py and models.py
• templates — from HTML files in templates/
• hooks — from register_template_hook() calls and get_template_hooks() slots in templates
• routes — true if the feature defines a blueprint

The section is always regenerated from source. To restrict what can be overridden, remove the code rather than editing the TOML.

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See also

• Refinement — how features use extension points
• Validation — guardrails that enforce extension points
• feature:contract — generate the extensible contract