fix(api): guard combo updates against emptying, and fix copilot combo targets (#10866)

Obrigado — bug real e bem raiz-causado, dois bugs da mesma família: (1) PUT /api/combos/<id> com models:[] zerava os targets sem aviso, quebrando um combo funcionando (o invariante "combo tem ≥1 modelo" já era reforçado por ~9 consumidores downstream, menos o write path); (2) as tools do Copilot escreviam em targets em vez de models, então todo combo criado via Copilot reportava sucesso mas roteava para lugar nenhum.

Validação (worktree combinado a partir de origin/release/v3.8.50, 0 conflitos):
- typecheck:core limpo, complexity/cognitive-complexity dentro do baseline
- tests/unit/combo-empty-models.test.ts — 4/4 passando
- Suíte combo completa (tests/unit/combo*.test.ts) — 1213 testes, 1208 passando, 5 falhas idênticas em ambos os lados (confirmadas DRIFT pré-existente do #9985 via probe contra o tip puro do release)

changelog.d/fixes/10866-combo-empty-models.md

@@ -0,0 +1 @@
+- fix(api): reject a combo update that removes every model, and store the copilot's combo targets where the router reads them (#10866)

src/lib/copilot/tools.ts

@@ -121,11 +121,7 @@ export const COPILOT_TOOLS: CopilotTool[] = [
       let output = `**${combos.length} combo(s) configured**\n\n`;
       for (const c of combos as any[]) {
         const active = c.isActive ? "✅" : "⛔";
-        const targets = c.targets
-          ? typeof c.targets === "string"
-            ? JSON.parse(c.targets).length
-            : c.targets.length
-          : 0;
+        const targets = Array.isArray(c.models) ? c.models.length : 0;
         output += `${active} **${c.name}** — strategy: \`${c.strategy}\` — ${targets} target(s)\n`;
       }
       return output;
@@ -165,7 +161,7 @@ export const COPILOT_TOOLS: CopilotTool[] = [
       const combo = await createCombo({
         name,
         strategy,
-        targets: JSON.stringify(targets),
+        models: targets,
         isActive: true,
       });
       const anyCombo = combo as any;

src/shared/validation/schemas/combo.ts

@@ -379,7 +379,12 @@ export const updateComboSchema = z
   .object({
     name: comboNameSchema.optional(),
     description: z.string().max(2000).optional().nullable(),
-    models: z.array(comboModelEntry).optional(),
+    // Creation may leave `models` empty (`omniroute combo create` drafts one
+    // that way); an update may not, or a working combo loses every target.
+    models: z
+      .array(comboModelEntry)
+      .min(1, "an update cannot remove every model from a combo")
+      .optional(),
     strategy: comboStrategySchema.optional(),
     config: comboRuntimeConfigSchema.optional(),
     isActive: z.boolean().optional(),

tests/unit/combo-empty-models.test.ts

@@ -0,0 +1,59 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import assert from "node:assert/strict";
+import test from "node:test";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-combo-empty-models-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const { createComboSchema, updateComboSchema } =
+  await import("../../src/shared/validation/schemas/combo.ts");
+const { getCopilotTool } = await import("../../src/lib/copilot/tools.ts");
+const combosDb = await import("../../src/lib/db/combos.ts");
+const core = await import("../../src/lib/db/core.ts");
+
+test.after(() => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+test("an update cannot remove every model from a combo", () => {
+  assert.equal(updateComboSchema.safeParse({ models: [] }).success, false);
+  assert.equal(updateComboSchema.safeParse({ models: ["openai/gpt-4o-mini"] }).success, true);
+  assert.equal(updateComboSchema.safeParse({ name: "renamed" }).success, true);
+});
+
+test("creating a combo with no model stays allowed — the CLI does it on purpose", () => {
+  assert.equal(createComboSchema.safeParse({ name: "drafted", models: [] }).success, true);
+  assert.equal(createComboSchema.safeParse({ name: "drafted" }).success, true);
+});
+
+test("the copilot createCombo tool stores targets where the router looks for them", async () => {
+  const tool = getCopilotTool("createCombo");
+  assert.ok(tool);
+
+  await tool.handler({
+    name: "copilot-stored",
+    strategy: "priority",
+    targets: JSON.stringify([{ provider: "openai", model: "gpt-4o-mini", weight: 100 }]),
+  });
+
+  const stored = (await combosDb.getComboByName("copilot-stored")) as { models?: unknown[] } | null;
+  assert.ok(stored, "the combo should exist");
+  assert.equal(stored.models?.length, 1);
+});
+
+test("the copilot combo list counts the targets the router will use", async () => {
+  const list = getCopilotTool("listCombos");
+  assert.ok(list);
+
+  await combosDb.createCombo({
+    name: "dashboard-made",
+    strategy: "priority",
+    models: ["openai/gpt-4o-mini", "openai/gpt-4o"],
+  });
+
+  const output = await list.handler({});
+  assert.match(output, /\*\*dashboard-made\*\* — strategy: `priority` — 2 target\(s\)/);
+});