Config Schema Inventory

Downstream. The OSS adapter ships the settings DSL, the naming policy and typed access by {slug}_config enum; see Settings & Config Keys, which also holds the DSL type-coverage table. The schema contract and the per-extension key inventory below belong to a proprietary package and product downstream. Names verified against the downstream code on 2026-11-04.

The schema contract

Each extension with settings keeps one string-backed {slug}_config enum as the single source of truth for its keys. Downstream, that enum implements ConfigSchemaInterface, which makes type, default and static options queryable at any lifecycle phase without loading services:

interface ConfigSchemaInterface {
    public function type(): string;     // host-specific type id (for Moodle, a SettingType value); treat as opaque
    public function default(): mixed;
    public function options(): ?array;  // null = no options, or options that need services (lazy)
    public function isLazy(): bool;     // true = options resolved at admin-page render time
}

Rules:

• A lazy setting returns options() === null; its real options are resolved only when the admin page renders, where services are available, never during register() or compile().
• The enum never resolves dynamic options itself; it only marks isLazy(). Resolution belongs to the settings DSL. This keeps the enum pure metadata, cheap to query at any phase.

Product key inventory (MIDDAG Moodle plugin)

This inventory belongs to the consumer product (the local_middag extensions), reproduced as the scale the schema mechanism was built for (reconstruction of April 2026).

Metric	Count
Extensions with a {slug}_config enum (of 12 product extensions)	10
Keys with storage	60
storedfile keys	3
multiselect keys	1
Lazy keys (isLazy() === true)	6

Extensions covered: core, ecommerce, videolibrary, automessage, bigquery, opengraph, cleaner, sentry, coursegroup, helpdesk.

• core has the largest enum, 15 keys, including authprofilefield (lazy, options from the user-field list) and authsecretkey (password type).
• bigquery has the most lazy options (4), for data retention and mode selection.

Anti-patterns

Anti-pattern	Why it is wrong
get_config() directly	Bypasses the typed schema; read through SettingsSupport / ConfigSupport
Resolution logic inside the {slug}_config enum	The enum must stay pure metadata
A config key with no matching enum case	A "ghost" key that never appears in the schema
Resolving lazy options during register()	Services are not available at that phase

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Decision records: MDL-011 and MDL-012 in middag-php-moodle/docs/decisions.