From b6d6cfd8d90d269f47c1b3073492e370585c6c80 Mon Sep 17 00:00:00 2001
From: Vignesh Natarajan <vigneshnatarajan92@gmail.com>
Date: Sat, 14 Feb 2026 19:33:35 -0800
Subject: [PATCH] test (gateway/config): cover config.patch agents.list
 merge-by-id

---
 src/config/merge-patch.test.ts              | 83 +++++++++++++++++++++
 src/gateway/server.config-patch.e2e.test.ts | 48 ++++++++++++
 2 files changed, 131 insertions(+)
 create mode 100644 src/config/merge-patch.test.ts

diff --git a/src/config/merge-patch.test.ts b/src/config/merge-patch.test.ts
new file mode 100644
index 00000000000..750d743d684
--- /dev/null
+++ b/src/config/merge-patch.test.ts
@@ -0,0 +1,83 @@
+import { describe, expect, it } from "vitest";
+import { applyMergePatch } from "./merge-patch.js";
+
+describe("applyMergePatch", () => {
+  it("replaces arrays by default", () => {
+    const base = {
+      agents: {
+        list: [
+          { id: "primary", workspace: "/tmp/one" },
+          { id: "secondary", workspace: "/tmp/two" },
+        ],
+      },
+    };
+    const patch = {
+      agents: {
+        list: [{ id: "primary", memorySearch: { extraPaths: ["/tmp/memory.md"] } }],
+      },
+    };
+
+    const merged = applyMergePatch(base, patch) as {
+      agents?: { list?: Array<{ id?: string; workspace?: string }> };
+    };
+    expect(merged.agents?.list).toEqual([
+      { id: "primary", memorySearch: { extraPaths: ["/tmp/memory.md"] } },
+    ]);
+  });
+
+  it("merges object arrays by id when enabled", () => {
+    const base = {
+      agents: {
+        list: [
+          { id: "primary", workspace: "/tmp/one" },
+          { id: "secondary", workspace: "/tmp/two" },
+        ],
+      },
+    };
+    const patch = {
+      agents: {
+        list: [{ id: "primary", memorySearch: { extraPaths: ["/tmp/memory.md"] } }],
+      },
+    };
+
+    const merged = applyMergePatch(base, patch, {
+      mergeObjectArraysById: true,
+    }) as {
+      agents?: {
+        list?: Array<{
+          id?: string;
+          workspace?: string;
+          memorySearch?: { extraPaths?: string[] };
+        }>;
+      };
+    };
+    expect(merged.agents?.list).toHaveLength(2);
+    const primary = merged.agents?.list?.find((entry) => entry.id === "primary");
+    const secondary = merged.agents?.list?.find((entry) => entry.id === "secondary");
+    expect(primary?.workspace).toBe("/tmp/one");
+    expect(primary?.memorySearch?.extraPaths).toEqual(["/tmp/memory.md"]);
+    expect(secondary?.workspace).toBe("/tmp/two");
+  });
+
+  it("falls back to replacement for non-id arrays even when enabled", () => {
+    const base = {
+      channels: {
+        telegram: { allowFrom: ["111", "222"] },
+      },
+    };
+    const patch = {
+      channels: {
+        telegram: { allowFrom: ["333"] },
+      },
+    };
+
+    const merged = applyMergePatch(base, patch, {
+      mergeObjectArraysById: true,
+    }) as {
+      channels?: {
+        telegram?: { allowFrom?: string[] };
+      };
+    };
+    expect(merged.channels?.telegram?.allowFrom).toEqual(["333"]);
+  });
+});
diff --git a/src/gateway/server.config-patch.e2e.test.ts b/src/gateway/server.config-patch.e2e.test.ts
index d2e57223bef..4ea6f08810e 100644
--- a/src/gateway/server.config-patch.e2e.test.ts
+++ b/src/gateway/server.config-patch.e2e.test.ts
@@ -43,6 +43,54 @@ describe("gateway config methods", () => {
     expect(res.ok).toBe(false);
     expect(res.error?.message ?? "").toContain("raw must be an object");
   });
+
+  it("merges agents.list entries by id instead of replacing the full array", async () => {
+    const setRes = await rpcReq<{ ok?: boolean }>(ws, "config.set", {
+      raw: JSON.stringify({
+        agents: {
+          list: [
+            { id: "primary", default: true, workspace: "/tmp/primary" },
+            { id: "secondary", workspace: "/tmp/secondary" },
+          ],
+        },
+      }),
+    });
+    expect(setRes.ok).toBe(true);
+    const snapshotRes = await rpcReq<{ hash?: string }>(ws, "config.get", {});
+    expect(snapshotRes.ok).toBe(true);
+    expect(typeof snapshotRes.payload?.hash).toBe("string");
+
+    const patchRes = await rpcReq<{
+      config?: {
+        agents?: {
+          list?: Array<{
+            id?: string;
+            workspace?: string;
+          }>;
+        };
+      };
+    }>(ws, "config.patch", {
+      baseHash: snapshotRes.payload?.hash,
+      raw: JSON.stringify({
+        agents: {
+          list: [
+            {
+              id: "primary",
+              workspace: "/tmp/primary-updated",
+            },
+          ],
+        },
+      }),
+    });
+    expect(patchRes.ok).toBe(true);
+
+    const list = patchRes.payload?.config?.agents?.list ?? [];
+    expect(list).toHaveLength(2);
+    const primary = list.find((entry) => entry.id === "primary");
+    const secondary = list.find((entry) => entry.id === "secondary");
+    expect(primary?.workspace).toBe("/tmp/primary-updated");
+    expect(secondary?.workspace).toBe("/tmp/secondary");
+  });
 });
 
 describe("gateway server sessions", () => {