fix(config): mark every unset field as default, including empty lists

The /config "default" marker keyed on isDefault, which was true only for an
unset field that *declares* a defaultValue — so an unset list with no default
(e.g. thread-creator's channels) showed "—" with no marker. Key it on !isSet
instead: any field the admin hasn't set is flagged. This also makes the marker
the exact complement of the reset picker (set ⟺ resettable ⟺ no marker). The
now-unused isDefault is removed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: AntoineJT

docs/site/en/guide/localization.md

@@ -63,7 +63,7 @@ The schema's `defaultValue` stays the English fallback. Defaults are **not persi
 
 Only `STRING` fields are localized this way. Enum defaults are stored identifiers (not display text) and are returned verbatim, as are numbers, booleans and lists.
 
-In the `/config` panel, a value still served by its default is flagged with a `config.defaultSuffix` marker (`_(default)_`), so an admin can tell at a glance what has actually been set. `ConfigProvider.isDefault(key)` exposes the same distinction in code.
+In the `/config` panel, any field the admin hasn't set — showing a default, or nothing for a field without one — is flagged with a `config.defaultSuffix` marker (`_(default)_`), so they can tell at a glance what has actually been changed. `ConfigProvider.isSet(key)` exposes the same distinction in code.
 
 > [!NOTE]
 > Guilds whose config predates this mechanism keep whatever default was already

docs/site/fr/guide/localisation.md

@@ -63,7 +63,7 @@ Le `defaultValue` du schéma reste le repli anglais. Les défauts ne sont **pas
 
 Seuls les champs `STRING` sont localisés ainsi. Les défauts d'enum sont des identifiants stockés (pas du texte affichable) et sont renvoyés tels quels, comme les nombres, booléens et listes.
 
-Dans le panneau `/config`, une valeur encore servie par son défaut est signalée par un marqueur `config.defaultSuffix` (`_(par défaut)_`), pour voir d'un coup d'œil ce qui a réellement été configuré. `ConfigProvider.isDefault(key)` expose la même distinction côté code.
+Dans le panneau `/config`, tout champ que l'admin n'a pas défini — affichant un défaut, ou rien pour un champ qui n'en a pas — est signalé par un marqueur `config.defaultSuffix` (`_(par défaut)_`), pour voir d'un coup d'œil ce qui a réellement été modifié. `ConfigProvider.isSet(key)` expose la même distinction côté code.
 
 > [!NOTE]
 > Les serveurs dont la config est antérieure à ce mécanisme conservent le défaut

src/core/utils/core-messages.ts

@@ -165,11 +165,11 @@ export const configurationMessage = <TSchema extends ConfigSchema>(
     const optDesc = config.t("config." + key + ".description", {
       defaultValue: option.description,
     });
-    // Flag values still served by their schema default, so an admin can tell
-    // at a glance what they have actually set versus what is just the default.
+    // Flag any field the admin hasn't set (showing a default — or nothing, for
+    // a field without one), so they can tell at a glance what they've changed.
     const renderedValue =
       renderCurrentValue(option, value, config.locale) +
-      (config.isDefault(key) ? config.t("config.defaultSuffix") : "");
+      (config.isSet(key) ? "" : config.t("config.defaultSuffix"));
     section.addTextDisplayComponents((text) =>
       text.setContent(
         config.t("config.option", {

src/lib/config.test.ts

@@ -263,36 +263,6 @@ describe("ConfigProvider default resolution", () => {
     expect(provider.get("greeting")).toBeUndefined();
   });
 
-  describe("isDefault", () => {
-    it("is true for an unset field that declares a default", () => {
-      const provider = new ConfigProvider(module, empty, "fr");
-      expect(provider.isDefault("note")).toBe(true);
-    });
-
-    it("is false once a value is stored", () => {
-      const provider = new ConfigProvider(
-        module,
-        { note: "stored" } as ConfigData<typeof schema>,
-        "fr"
-      );
-      expect(provider.isDefault("note")).toBe(false);
-    });
-
-    it("is false for an unset field without a default", () => {
-      const provider = new ConfigProvider(module, empty, "fr");
-      expect(provider.isDefault("greeting")).toBe(false);
-    });
-
-    it("treats a cleared value (null) as explicitly set, not default", () => {
-      const provider = new ConfigProvider(
-        module,
-        { note: null } as unknown as ConfigData<typeof schema>,
-        "fr"
-      );
-      expect(provider.isDefault("note")).toBe(false);
-    });
-  });
-
   describe("isSet", () => {
     it("is false when nothing is stored (default in use)", () => {
       const provider = new ConfigProvider(module, empty, "fr");

src/lib/config.ts

@@ -268,23 +268,10 @@ export class ConfigProvider<TSchema extends ConfigSchema> {
   }
 
   /**
-   * Whether `get(key)` is currently serving the schema default rather than a
-   * stored value — true only when nothing is stored and the entry declares a
-   * default. A cleared value (`null`) counts as explicitly set, not default.
-   * Lets the UI flag which values the admin has actually chosen.
-   */
-  isDefault<TKey extends keyof TSchema>(key: TKey): boolean {
-    if (this.data[key] !== undefined) {
-      return false;
-    }
-    return this.module.config[key]?.defaultValue !== undefined;
-  }
-
-  /**
-   * Whether `key` holds an explicitly stored value (including a `null` clear) —
-   * i.e. something a reset could remove to fall back to the default. Distinct
-   * from `!isDefault`: a field with neither a stored value nor a default is not
-   * "set" yet not "default" either.
+   * Whether `key` holds an explicitly stored value (including a `null` clear).
+   * Its negation means the admin has not set the field: `get(key)` is serving a
+   * default — or simply nothing, for a field without one. The UI flags such
+   * values as "default" and a reset only ever touches set fields.
    */
   isSet<TKey extends keyof TSchema>(key: TKey): boolean {
     return this.data[key] !== undefined;