fix: harden discord agent cid parsing (#29013) (thanks @Jacky1n7)

src/discord/monitor/agent-components.ts

@@ -406,22 +406,21 @@ export function buildAgentSelectCustomId(componentId: string): string {
 
 /**
  * Parse agent component data from Carbon's parsed ComponentData
- * Carbon parses "key:componentId=xxx" into { componentId: "xxx" }
+ * Supports both legacy { componentId } and Components v2 { cid } payloads.
  */
+function readParsedComponentId(data: ComponentData): unknown {
+  if (!data || typeof data !== "object") {
+    return undefined;
+  }
+  return "cid" in data
+    ? (data as Record<string, unknown>).cid
+    : (data as Record<string, unknown>).componentId;
+}
+
 function parseAgentComponentData(data: ComponentData): {
   componentId: string;
 } | null {
-  if (!data || typeof data !== "object") {
-    return null;
-  }
-
-  // Carbon parses "key:componentId=xxx" into { componentId: "xxx" }
-  // Components v2 / other builders may use { cid: "xxx" } (e.g. occomp:cid=xxx).
-  const raw =
-    ("cid" in data
-      ? (data as Record<string, unknown>).cid
-      : (data as Record<string, unknown>).componentId) ??
-    (data as Record<string, unknown>).componentId;
+  const raw = readParsedComponentId(data);
 
   const decodeSafe = (value: string): string => {
     // `cid` values may be raw (not URI-encoded). Guard against malformed % sequences.
@@ -601,10 +600,7 @@ function parseDiscordComponentData(
   if (!data || typeof data !== "object") {
     return null;
   }
-  const rawComponentId =
-    "cid" in data
-      ? (data as { cid?: unknown }).cid
-      : (data as { componentId?: unknown }).componentId;
+  const rawComponentId = readParsedComponentId(data);
   const rawModalId =
     "mid" in data ? (data as { mid?: unknown }).mid : (data as { modalId?: unknown }).modalId;
   let componentId = normalizeComponentId(rawComponentId);

src/discord/monitor/monitor.test.ts

@@ -182,6 +182,44 @@ describe("agent components", () => {
     expect(reply).toHaveBeenCalledWith({ content: "✓" });
     expect(enqueueSystemEventMock).toHaveBeenCalled();
   });
+
+  it("accepts cid payloads for agent button interactions", async () => {
+    const button = createAgentComponentButton({
+      cfg: createCfg(),
+      accountId: "default",
+      dmPolicy: "allowlist",
+      allowFrom: ["123456789"],
+    });
+    const { interaction, defer, reply } = createDmButtonInteraction();
+
+    await button.run(interaction, { cid: "hello_cid" } as ComponentData);
+
+    expect(defer).toHaveBeenCalledWith({ ephemeral: true });
+    expect(reply).toHaveBeenCalledWith({ content: "✓" });
+    expect(enqueueSystemEventMock).toHaveBeenCalledWith(
+      expect.stringContaining("hello_cid"),
+      expect.any(Object),
+    );
+  });
+
+  it("keeps malformed percent cid values without throwing", async () => {
+    const button = createAgentComponentButton({
+      cfg: createCfg(),
+      accountId: "default",
+      dmPolicy: "allowlist",
+      allowFrom: ["123456789"],
+    });
+    const { interaction, defer, reply } = createDmButtonInteraction();
+
+    await button.run(interaction, { cid: "hello%2G" } as ComponentData);
+
+    expect(defer).toHaveBeenCalledWith({ ephemeral: true });
+    expect(reply).toHaveBeenCalledWith({ content: "✓" });
+    expect(enqueueSystemEventMock).toHaveBeenCalledWith(
+      expect.stringContaining("hello%2G"),
+      expect.any(Object),
+    );
+  });
 });
 
 describe("discord component interactions", () => {