fix(discord): omit undefined component registry fields

Prunes undefined Discord component and modal registry metadata before persisting it so SQLite-backed plugin state never receives JSON-incompatible undefined values. Adds direct regression coverage for undefined own properties on component, modal, and nested field entries.

extensions/discord/src/components-registry.ts

@@ -176,6 +176,25 @@ function normalizeEntryTimestamps<T extends { createdAt?: number; expiresAt?: nu
   return { ...entry, createdAt, expiresAt };
 }
 
+function pruneUndefinedRegistryValues<T>(value: T): T {
+  if (Array.isArray(value)) {
+    return value
+      .filter((entry) => entry !== undefined)
+      .map((entry) => pruneUndefinedRegistryValues(entry)) as T;
+  }
+  if (!value || typeof value !== "object") {
+    return value;
+  }
+  const result: Record<string, unknown> = {};
+  for (const [key, entry] of Object.entries(value)) {
+    if (entry === undefined) {
+      continue;
+    }
+    result[key] = pruneUndefinedRegistryValues(entry);
+  }
+  return result as T;
+}
+
 function registerEntries<
   T extends { id: string; messageId?: string; createdAt?: number; expiresAt?: number },
 >(
@@ -237,8 +256,9 @@ function registerPersistentRegistryEntries<T extends { id: string }>(params: {
     return;
   }
   for (const entry of params.entries) {
+    const persistedEntry = pruneUndefinedRegistryValues(entry);
     void store
-      .register(entry.id, { version: 1, entry }, { ttlMs: params.ttlMs })
+      .register(entry.id, { version: 1, entry: persistedEntry }, { ttlMs: params.ttlMs })
       .catch(disablePersistentComponentRegistry);
   }
 }

extensions/discord/src/components.test.ts

@@ -1,5 +1,6 @@
 import { ButtonStyle, MessageFlags } from "discord-api-types/v10";
 import { beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import type { DiscordComponentEntry, DiscordModalEntry } from "./components.js";
 
 let clearDiscordComponentEntries: typeof import("./components-registry.js").clearDiscordComponentEntries;
 let registerDiscordComponentEntries: typeof import("./components-registry.js").registerDiscordComponentEntries;
@@ -468,6 +469,92 @@ describe("discord component registry", () => {
     expect(openKeyedStore).toHaveBeenCalledTimes(4);
   });
 
+  it("omits undefined component fields before persisting registry state", async () => {
+    const componentRegister = vi.fn().mockResolvedValue(undefined);
+    const modalRegister = vi.fn().mockResolvedValue(undefined);
+    const componentStore = {
+      register: componentRegister,
+      lookup: vi.fn(),
+      consume: vi.fn(),
+      delete: vi.fn(),
+      entries: vi.fn(),
+      clear: vi.fn(),
+    };
+    const modalStore = {
+      register: modalRegister,
+      lookup: vi.fn(),
+      consume: vi.fn(),
+      delete: vi.fn(),
+      entries: vi.fn(),
+      clear: vi.fn(),
+    };
+    const openKeyedStore = vi.fn((opts: { namespace: string }) =>
+      opts.namespace === "discord.components" ? componentStore : modalStore,
+    );
+    const { setDiscordRuntime } = await import("./runtime.js");
+    setDiscordRuntime({
+      state: { openKeyedStore },
+      logging: { getChildLogger: () => ({ warn: vi.fn() }) },
+    } as never);
+
+    const componentEntry = Object.assign(
+      {
+        id: "btn_undefined",
+        kind: "button",
+        label: "Approve",
+        callbackData: "approve",
+      } satisfies DiscordComponentEntry,
+      { modalId: undefined, sessionKey: undefined },
+    );
+    const modalEntry = Object.assign(
+      {
+        id: "mdl_undefined",
+        title: "Details",
+        fields: [
+          Object.assign(
+            {
+              id: "fld_undefined",
+              name: "reason",
+              label: "Reason",
+              type: "text",
+            } satisfies DiscordModalEntry["fields"][number],
+            { description: undefined, placeholder: undefined },
+          ),
+        ],
+      } satisfies DiscordModalEntry,
+      { sessionKey: undefined },
+    );
+
+    registerDiscordComponentEntries({
+      entries: [componentEntry],
+      modals: [modalEntry],
+      ttlMs: 1000,
+    });
+
+    await vi.waitFor(() => expect(componentRegister).toHaveBeenCalledTimes(1));
+    expect(modalRegister).toHaveBeenCalledTimes(1);
+
+    const persistedComponent = componentRegister.mock.calls[0]?.[1] as
+      | { entry: Record<string, unknown> }
+      | undefined;
+    expect(persistedComponent?.entry.callbackData).toBe("approve");
+    expect(persistedComponent?.entry).not.toHaveProperty("modalId");
+    expect(persistedComponent?.entry).not.toHaveProperty("sessionKey");
+    expect(persistedComponent?.entry).not.toHaveProperty("messageId");
+
+    const modalPayload = modalRegister.mock.calls[0]?.[1] as
+      | { entry: { fields?: Array<Record<string, unknown>> } }
+      | undefined;
+    expect(modalPayload?.entry.fields?.[0]).not.toHaveProperty("description");
+    expect(modalPayload?.entry.fields?.[0]).not.toHaveProperty("placeholder");
+    expect(modalPayload?.entry).not.toHaveProperty("sessionKey");
+    expect(modalPayload?.entry).not.toHaveProperty("messageId");
+
+    const inMemoryComponent = resolveDiscordComponentEntry({ id: "btn_undefined", consume: false });
+    expect(inMemoryComponent).toHaveProperty("modalId", undefined);
+    expect(inMemoryComponent).toHaveProperty("sessionKey", undefined);
+  });
+
   it("deletes sibling persistent component entries when a group entry is consumed", async () => {
     const componentDelete = vi.fn().mockResolvedValue(true);
     const componentStore = {