fix(deps): upgrade dependency chain through Next.js 16, fix generated tsconfig detection

.github/workflows/test.yml

@@ -54,6 +54,9 @@ jobs:
       - name: Run tsc in nextjs-app
         run: pnpm --filter nextjs-app test:generated
 
+      - name: Run next build in nextjs-app
+        run: pnpm --filter nextjs-app build
+
       - name: Run tsc in tanstack-router-app
         run: pnpm --filter tanstack-router-app test:generated
 

examples/nextjs-app/package.json

@@ -8,15 +8,14 @@
     "dev:mock": "prism mock ../petstore.yaml --dynamic",
     "build": "next build",
     "start": "next start",
-    "lint": "next lint",
     "generate:api": "rimraf ./openapi && node ../../dist/cli.mjs -i ../petstore.yaml --format=biome --lint=biome",
     "test:generated": "tsc -p ./tsconfig.json --noEmit"
   },
   "dependencies": {
     "@hey-api/client-fetch": "^0.6.0",
     "@tanstack/react-query": "^5.59.13",
     "@tanstack/react-query-devtools": "^5.32.1",
-    "next": "^15.5.16",
+    "next": "^16.2.10",
     "react": "^18",
     "react-dom": "^18"
   },

examples/nextjs-app/tsconfig.json

@@ -11,7 +11,7 @@
     "moduleResolution": "bundler",
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "jsx": "preserve",
+    "jsx": "react-jsx",
     "incremental": true,
     "plugins": [
       {
@@ -22,6 +22,12 @@
       "@/*": ["./*"]
     }
   },
-  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts"
+  ],
   "exclude": ["node_modules"]
 }

src/generate.mts

@@ -1,4 +1,5 @@
-import { writeFile } from "node:fs/promises";
+import { readdirSync } from "node:fs";
+import { readFile, writeFile } from "node:fs/promises";
 import path from "node:path";
 import { type UserConfig, createClient } from "@hey-api/openapi-ts";
 import type { LimitedUserConfig } from "./cli.mjs";
@@ -11,6 +12,27 @@ import { createSource } from "./createSource.mjs";
 import { formatOutput, processOutput } from "./format.mjs";
 import { print } from "./print.mjs";
 
+// openapi-ts's own tsconfig auto-detection walks up from its *install*
+// location, which in this monorepo reaches this repo's own root tsconfig
+// (NodeNext) instead of the caller's project config. Anchoring the search
+// at cwd instead finds the tsconfig that actually applies to the generated
+// output, matching the resolution the caller's own `tsc` will use.
+export function findNearestTsConfigPath(startDir: string): string | undefined {
+  let dir = startDir;
+  while (true) {
+    const candidates = readdirSync(dir).filter(
+      (file) => file.startsWith("tsconfig") && file.endsWith(".json"),
+    );
+    if (candidates.length > 0) {
+      candidates.sort((a) => (a === "tsconfig.json" ? -1 : 1));
+      return path.join(dir, candidates[0]);
+    }
+    const parent = path.dirname(dir);
+    if (parent === dir) return undefined;
+    dir = parent;
+  }
+}
+
 export async function generate(options: LimitedUserConfig, version: string) {
   const openApiOutputPath = buildRequestsOutputPath(options.output);
   const formattedOptions = formatOptions(options);
@@ -61,14 +83,25 @@ export async function generate(options: LimitedUserConfig, version: string) {
   const config: UserConfig = {
     dryRun: false,
     input: formattedOptions.input,
-    output: openApiOutputPath,
+    output: {
+      path: openApiOutputPath,
+      tsConfigPath: findNearestTsConfigPath(process.cwd()) ?? null,
+    },
     plugins,
   };
   await createClient(config);
 
   // Generate backward-compatible services.gen.ts shim
-  // client.gen.ts has the `client` instance; sdk.gen.ts has SDK functions
-  const shimContent = `// This file is auto-generated for backward compatibility\nexport * from './client.gen.js';\nexport * from './sdk.gen.js';\n`;
+  // client.gen.ts has the `client` instance; sdk.gen.ts has SDK functions.
+  // Mirror whatever extension convention openapi-ts used for its own
+  // cross-file imports (e.g. `.js` for NodeNext, none for bundler resolution).
+  const sdkGenContent = await readFile(
+    path.join(openApiOutputPath, "sdk.gen.ts"),
+    "utf-8",
+  );
+  const importExtension =
+    sdkGenContent.match(/from ['"]\.\/client\.gen(\.\S*)?['"]/)?.[1] ?? "";
+  const shimContent = `// This file is auto-generated for backward compatibility\nexport * from './client.gen${importExtension}';\nexport * from './sdk.gen${importExtension}';\n`;
   await writeFile(path.join(openApiOutputPath, "services.gen.ts"), shimContent);
 
   const source = await createSource({