chore: import upstream snapshot with attribution

tests/unit/opencode-deepseek-reasoning-injected.test.ts

@@ -0,0 +1,94 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+
+const { OpencodeExecutor } = await import("../../open-sse/executors/opencode.ts");
+
+/**
+ * Regression test for upstream decolua/9router#1099 (issue #1543):
+ *
+ * OpenCode is a meta-provider that proxies multi-turn chats to thinking-mode
+ * upstreams (DeepSeek V4 Flash, Kimi, MiniMax, ...). Those upstreams require
+ * `reasoning_content` to be echoed back on every assistant message in the
+ * conversation history; otherwise they return:
+ *
+ *     400 Bad Request — reasoning_content must be passed back
+ *
+ * Standard OpenAI clients do not preserve `reasoning_content` across turns, so
+ * OpencodeExecutor.transformRequest must inject a non-empty placeholder on any
+ * assistant message that lacks it when routing to a thinking-mode model.
+ */
+describe("OpencodeExecutor — DeepSeek reasoning_content injection (#1099)", () => {
+  const executor = new OpencodeExecutor("opencode-zen");
+
+  function buildBody(extraAssistant: Record<string, unknown>) {
+    return {
+      model: "oc/deepseek-v4-flash-free",
+      stream: true,
+      messages: [
+        { role: "user", content: "hi" },
+        { role: "assistant", content: "previous answer", ...extraAssistant },
+        { role: "user", content: "follow up" },
+      ],
+    };
+  }
+
+  it("injects reasoning_content on an assistant message that lacks it (deepseek model)", () => {
+    const out = executor.transformRequest(
+      "oc/deepseek-v4-flash-free",
+      buildBody({}),
+      true,
+      { apiKey: "test" } as never
+    );
+    const assistant = out.messages.find((m: { role: string }) => m.role === "assistant");
+    assert.equal(typeof assistant.reasoning_content, "string");
+    assert.ok(
+      assistant.reasoning_content.length > 0,
+      "expected non-empty reasoning_content placeholder injected"
+    );
+  });
+
+  it("preserves an existing non-empty reasoning_content instead of overwriting", () => {
+    const original = "prior chain of thought";
+    const out = executor.transformRequest(
+      "oc/deepseek-v4-flash-free",
+      buildBody({ reasoning_content: original }),
+      true,
+      { apiKey: "test" } as never
+    );
+    const assistant = out.messages.find((m: { role: string }) => m.role === "assistant");
+    assert.equal(assistant.reasoning_content, original);
+  });
+
+  it("injects for kimi-family models routed through opencode", () => {
+    const body = {
+      model: "oc/kimi-k2-thinking",
+      stream: false,
+      messages: [
+        { role: "user", content: "hi" },
+        { role: "assistant", content: "answer" },
+      ],
+    };
+    const out = executor.transformRequest("oc/kimi-k2-thinking", body, false, {
+      apiKey: "test",
+    } as never);
+    const assistant = out.messages.find((m: { role: string }) => m.role === "assistant");
+    assert.equal(typeof assistant.reasoning_content, "string");
+    assert.ok(assistant.reasoning_content.length > 0);
+  });
+
+  it("does not inject for non-thinking opencode models (no false positives)", () => {
+    const body = {
+      model: "oc/gpt-5",
+      stream: false,
+      messages: [
+        { role: "user", content: "hi" },
+        { role: "assistant", content: "answer" },
+      ],
+    };
+    const out = executor.transformRequest("oc/gpt-5", body, false, {
+      apiKey: "test",
+    } as never);
+    const assistant = out.messages.find((m: { role: string }) => m.role === "assistant");
+    assert.equal(assistant.reasoning_content, undefined);
+  });
+});