fix(translator): use non-empty reasoning_content placeholder on cache miss instead of empty string (#3433)

Integrated into release/v3.8.17

open-sse/translator/index.ts

@@ -294,7 +294,6 @@ export function translateRequest(
     thinkingEnabled: hasThinkingConfig(result),
     supportsReasoning: supportsReasoning({ provider: normalizedProvider, model: normalizedModel }),
     interleavedField: resolvedCapabilities?.interleavedField ?? null,
-    allowLegacyFallback: false,
   });
   if (isReasoner && result.messages && Array.isArray(result.messages)) {
     const canReplayReasoningOnly = isDeepSeekReplayTarget(normalizedProvider, normalizedModel);
@@ -370,9 +369,14 @@ export function translateRequest(
         }
       }
 
-      // Legacy fallback — empty string (works for older DeepSeek versions)
-      if (hasToolCalls && msg.reasoning_content === undefined) {
-        msg.reasoning_content = "";
+      // Cache miss fallback — use a non-empty placeholder.
+      // Empty string causes DeepSeek V4+ to reject with 400:
+      // "reasoning_content in the thinking mode must be passed back to the API."
+      // Note: injectEmptyReasoningContentForToolCalls may have pre-set
+      // reasoning_content="" before the cache lookup, so we check for
+      // both undefined AND empty string here.
+      if (hasToolCalls && !msg.reasoning_content) {
+        msg.reasoning_content = NON_ANTHROPIC_THINKING_PLACEHOLDER;
       }
     }
   } else if (

src/app/api/system/version/route.ts

@@ -14,6 +14,7 @@ import {
   getAutoUpdateConfig,
   launchAutoUpdate,
   validateAutoUpdateRuntime,
+  PROJECT_ROOT,
 } from "@/lib/system/autoUpdate";
 import { NEWS_JSON_URL, parseActiveNewsPayload } from "@/shared/utils/releaseNotes";
 
@@ -169,7 +170,7 @@ export async function POST(req: NextRequest) {
           });
           await execFileAsync("git", ["fetch", "--tags", config.gitRemote], {
             timeout: 60_000,
-            cwd: process.cwd(),
+            cwd: PROJECT_ROOT,
           });
           send({ step: "install", status: "done", message: "Tags fetched" });
 
@@ -178,7 +179,7 @@ export async function POST(req: NextRequest) {
             status: "running",
             message: `Validating ${resolvedTargetTag}...`,
           });
-          await ensureGitTagExists(resolvedTargetTag, execFileAsync, process.cwd());
+          await ensureGitTagExists(resolvedTargetTag, execFileAsync, PROJECT_ROOT);
           send({
             step: "install",
             status: "done",
@@ -193,7 +194,7 @@ export async function POST(req: NextRequest) {
           try {
             await execFileAsync("git", ["stash", "--include-untracked"], {
               timeout: 30_000,
-              cwd: process.cwd(),
+              cwd: PROJECT_ROOT,
             });
           } catch {
             // No local changes to stash.
@@ -202,7 +203,7 @@ export async function POST(req: NextRequest) {
           const shortHead = (
             await execFileAsync("git", ["rev-parse", "--short", "HEAD"], {
               timeout: 10_000,
-              cwd: process.cwd(),
+              cwd: PROJECT_ROOT,
             })
           ).stdout.trim();
           const backupBranch = `pre-update/${shortHead}-${new Date().toISOString().replace(/[:.]/g, "-")}`;
@@ -210,7 +211,7 @@ export async function POST(req: NextRequest) {
           try {
             await execFileAsync("git", ["branch", backupBranch], {
               timeout: 10_000,
-              cwd: process.cwd(),
+              cwd: PROJECT_ROOT,
             });
           } catch {
             // Backup branch is best-effort only.
@@ -218,7 +219,7 @@ export async function POST(req: NextRequest) {
 
           await execFileAsync("git", ["checkout", resolvedTargetTag], {
             timeout: 30_000,
-            cwd: process.cwd(),
+            cwd: PROJECT_ROOT,
           });
           send({ step: "install", status: "done", message: `Checked out ${resolvedTargetTag}` });
 
@@ -229,14 +230,14 @@ export async function POST(req: NextRequest) {
           });
           await execFileAsync("npm", ["install", "--legacy-peer-deps"], {
             timeout: 300_000,
-            cwd: process.cwd(),
+            cwd: PROJECT_ROOT,
           });
           send({ step: "rebuild", status: "done", message: "Dependencies installed" });
 
           try {
             await execFileAsync("node", ["scripts/dev/sync-env.mjs"], {
               timeout: 15_000,
-              cwd: process.cwd(),
+              cwd: PROJECT_ROOT,
             });
           } catch {
             // .env sync is non-fatal during update.
@@ -249,7 +250,7 @@ export async function POST(req: NextRequest) {
           });
           await execFileAsync("npm", ["run", "build"], {
             timeout: 600_000,
-            cwd: process.cwd(),
+            cwd: PROJECT_ROOT,
           });
           send({ step: "rebuild", status: "done", message: "Build complete" });
 
@@ -257,7 +258,7 @@ export async function POST(req: NextRequest) {
           try {
             await execFileAsync("pm2", ["restart", "omniroute", "--update-env"], {
               timeout: 30_000,
-              cwd: process.cwd(),
+              cwd: PROJECT_ROOT,
             });
             send({ step: "restart", status: "done", message: "Service restarted" });
           } catch {
@@ -306,13 +307,14 @@ export async function POST(req: NextRequest) {
       try {
         // Step 1: Install
         send({ step: "install", status: "running", message: `Installing omniroute@${latest}...` });
-        await execFileAsync(
-          "npm",
-          ["install", "-g", `omniroute@${latest}`, "--ignore-scripts", "--legacy-peer-deps"],
-          {
-            timeout: 300000,
-          }
-        );
+          await execFileAsync(
+            "npm",
+            ["install", "-g", `omniroute@${latest}`, "--ignore-scripts", "--legacy-peer-deps"],
+            {
+              timeout: 300000,
+              cwd: PROJECT_ROOT,
+            }
+          );
         send({ step: "install", status: "done", message: `Installed omniroute@${latest}` });
 
         // Step 2: Rebuild native modules (critical for better-sqlite3)
@@ -321,29 +323,36 @@ export async function POST(req: NextRequest) {
           status: "running",
           message: "Rebuilding native modules (better-sqlite3)...",
         });
-        const globalRoot = (
-          await execFileAsync("npm", ["root", "-g"], { timeout: 10000 })
-        ).stdout.trim();
+          const globalRoot = (
+            await execFileAsync("npm", ["root", "-g"], { timeout: 10000, cwd: PROJECT_ROOT })
+          ).stdout.trim();
         const omniPath = `${globalRoot}/omniroute/app`;
-        await execFileAsync("npm", ["rebuild", "better-sqlite3"], {
-          cwd: omniPath,
-          timeout: 120000,
-        });
+        await execFileAsync(
+          "npm",
+          ["rebuild", "better-sqlite3"],
+          {
+            cwd: omniPath,
+            timeout: 120000,
+          }
+        );
         send({ step: "rebuild", status: "done", message: "Native modules rebuilt" });
 
         // Step 3: Restart PM2
         send({ step: "restart", status: "running", message: "Restarting service via PM2..." });
-        try {
-          await execFileAsync("pm2", ["restart", "omniroute", "--update-env"], { timeout: 30000 });
-          send({ step: "restart", status: "done", message: "Service restarted" });
-        } catch {
-          // PM2 may not be available (Docker/manual setups)
-          send({
-            step: "restart",
-            status: "skipped",
-            message: "PM2 not available — manual restart needed",
-          });
-        }
+          try {
+            await execFileAsync("pm2", ["restart", "omniroute", "--update-env"], {
+              timeout: 30000,
+              cwd: PROJECT_ROOT,
+            });
+            send({ step: "restart", status: "done", message: "Service restarted" });
+          } catch {
+            // PM2 may not be available (Docker/manual setups)
+            send({
+              step: "restart",
+              status: "skipped",
+              message: "PM2 not available — manual restart needed",
+            });
+          }
 
         send({
           step: "complete",

src/lib/system/autoUpdate.ts

@@ -3,9 +3,24 @@ import { closeSync, mkdirSync, openSync, existsSync } from "node:fs";
 import { access } from "node:fs/promises";
 import path from "node:path";
 import { promisify } from "node:util";
+import { homedir } from "node:os";
 
 const execFileAsync = promisify(execFile);
 
+function resolveProjectRoot(fallback: string): string {
+  try {
+    const cwd = process.cwd();
+    if (existsSync(path.join(cwd, "package.json"))) return cwd;
+    if (existsSync(path.join(cwd, ".git"))) return cwd;
+    return cwd;
+  } catch {
+    return fallback;
+  }
+}
+
+const FALLBACK_CWD = process.env.HOME || homedir() || "/tmp";
+export const PROJECT_ROOT: string = resolveProjectRoot(FALLBACK_CWD);
+
 type ComposeCommand = "docker compose" | "docker-compose";
 export type AutoUpdateMode = "npm" | "docker-compose" | "source";
 
@@ -70,8 +85,8 @@ export function getAutoUpdateConfig(env: NodeJS.ProcessEnv = process.env): AutoU
 
   let mode = normalizeMode(env.AUTO_UPDATE_MODE);
   if (mode === "npm") {
-    const isGitRepo = existsSync(path.join(process.cwd(), ".git"));
-    const currentDir = typeof __dirname !== "undefined" ? __dirname : process.cwd();
+    const isGitRepo = existsSync(path.join(PROJECT_ROOT, ".git"));
+    const currentDir = typeof __dirname !== "undefined" ? __dirname : PROJECT_ROOT;
     const isGlobalNodeModules = currentDir.includes("node_modules");
 
     // If we are not in a global node_modules directory, we are likely a local source install/build.
@@ -117,7 +132,7 @@ export async function validateAutoUpdateRuntime(
   existsImpl: (targetPath: string) => Promise<boolean> = pathExists
 ): Promise<AutoUpdateValidation> {
   if (config.mode === "source") {
-    const gitDir = path.join(process.cwd(), ".git");
+    const gitDir = path.join(PROJECT_ROOT, ".git");
     if (!(await existsImpl(gitDir))) {
       return {
         supported: false,
@@ -197,7 +212,7 @@ export async function validateAutoUpdateRuntime(
 export async function ensureGitTagExists(
   targetTag: string,
   execFileImpl: ExecFileLike = execFileAsync,
-  cwd = process.cwd()
+  cwd = PROJECT_ROOT
 ): Promise<void> {
   try {
     await execFileImpl("git", ["rev-parse", "-q", "--verify", `refs/tags/${targetTag}`], {

tests/unit/reasoning-cache.test.ts

@@ -754,6 +754,62 @@ describe("Reasoning Replay Cache — Translator Replay", () => {
 
     assert.equal(translated.messages[1].reasoning_content, undefined);
   });
+
+  it("should replace empty-string reasoning_content with NON_ANTHROPIC_THINKING_PLACEHOLDER on cache miss", async () => {
+    // Regression: injectEmptyReasoningContentForToolCalls (schemaCoercion.ts) pre-sets
+    // reasoning_content="" before the cache lookup. The old condition
+    // `msg.reasoning_content === undefined` never fired on cache miss, leaving the
+    // empty string in place. DeepSeek V4+ rejects "" with a 400.
+    clearReasoningCacheAll();
+    clearModelsDevCapabilities();
+    saveModelsDevCapabilities({
+      deepseek: {
+        "deepseek-v4-flash": buildCapability({
+          interleaved_field: "reasoning_content",
+          reasoning: true,
+          tool_call: true,
+        }),
+      },
+    });
+
+    const { NON_ANTHROPIC_THINKING_PLACEHOLDER } = await import(
+      "../../open-sse/translator/helpers/claudeHelper.ts"
+    );
+
+    // No cache entry → cache miss
+    const translated = translateRequest(
+      FORMATS.OPENAI,
+      FORMATS.OPENAI,
+      "deepseek-v4-flash",
+      {
+        messages: [
+          { role: "user", content: "use a tool" },
+          {
+            role: "assistant",
+            content: null,
+            reasoning_content: "",
+            tool_calls: [
+              {
+                id: "call_empty_rc",
+                type: "function",
+                function: { name: "read_file", arguments: "{}" },
+              },
+            ],
+          },
+          { role: "tool", tool_call_id: "call_empty_rc", content: "file contents" },
+        ],
+      },
+      false,
+      null,
+      "deepseek"
+    );
+
+    assert.equal(
+      translated.messages[1].reasoning_content,
+      NON_ANTHROPIC_THINKING_PLACEHOLDER,
+      "empty reasoning_content should be replaced with placeholder on cache miss"
+    );
+  });
 });
 
 describe("Reasoning Replay Cache — API Route", () => {