fix(@langchain/core): update and bundle dependencies (#9534)

Author: christian-bromann

.changeset/eight-mangos-visit.md

@@ -0,0 +1,5 @@
+---
+"@langchain/core": patch
+---
+
+fix(@langchain/core): update and bundle `p-retry`, `ansi-styles`, `camelcase` and `decamelize` dependencies

environment_tests/scripts/test-runner.ts

@@ -82,12 +82,14 @@ class EnvironmentTestRunner {
    * Copy a directory from src to dest, excluding files that match the excludePatterns
    * @param src - The source directory
    * @param dest - The destination directory
-   * @param excludePatterns - An array of file names to exclude from the copy
+   * @param excludePatterns - An array of file names to exclude from the copy (only at the top level)
+   * @param isTopLevel - Whether this is the top level call (used to only apply excludePatterns at root)
    */
   private async copyDirectory(
     src: string,
     dest: string,
-    excludePatterns: string[] = []
+    excludePatterns: string[] = [],
+    isTopLevel: boolean = true
   ): Promise<void> {
     await fs.mkdir(dest, { recursive: true });
 
@@ -98,13 +100,17 @@ class EnvironmentTestRunner {
         const srcPath = path.join(src, entry.name);
         const destPath = path.join(dest, entry.name);
 
-        // Skip excluded patterns
-        if (excludePatterns.some((pattern) => entry.name === pattern)) {
+        // Skip excluded patterns only at the top level
+        // This allows dist/node_modules (bundled dependencies) to be copied
+        if (
+          isTopLevel &&
+          excludePatterns.some((pattern) => entry.name === pattern)
+        ) {
           return;
         }
 
         if (entry.isDirectory()) {
-          await this.copyDirectory(srcPath, destPath, excludePatterns);
+          await this.copyDirectory(srcPath, destPath, excludePatterns, false);
         } else {
           await fs.copyFile(srcPath, destPath);
         }
@@ -227,12 +233,10 @@ class EnvironmentTestRunner {
           return;
         }
 
-        let destDirName: string;
-        if (pkg.name === "langchain") {
-          destDirName = "langchain";
-        } else {
-          destDirName = pkg.name.replace("@langchain/", "langchain-");
-        }
+        const destDirName: string =
+          pkg.name === "langchain"
+            ? "langchain"
+            : pkg.name.replace("@langchain/", "langchain-");
         const destDir = path.join(libsDir, destDirName);
         await fs.mkdir(destDir, { recursive: true });
 

libs/langchain-core/eslint.config.ts

@@ -1,9 +1,23 @@
 import { langchainConfig, type ConfigArray } from "@langchain/eslint";
 
+/**
+ * Packages bundled via `noExternal` in tsdown.config.ts.
+ * These packages are ESM-only and bundled into the output for CJS compatibility.
+ * They only need to be devDependencies, not runtime dependencies.
+ * Listed here as core-modules so import/no-extraneous-dependencies ignores them.
+ */
+const bundledPackages = ["p-retry", "ansi-styles", "camelcase", "decamelize"];
+
 const config: ConfigArray = [
   ...langchainConfig,
   {
     ignores: ["src/utils/zod-to-json-schema/**"],
   },
+  {
+    // Treat bundled packages as core modules so they don't need to be in dependencies
+    settings: {
+      "import/core-modules": bundledPackages,
+    },
+  },
 ];
 export default config;

libs/langchain-core/package.json

@@ -31,14 +31,10 @@
   "license": "MIT",
   "dependencies": {
     "@cfworker/json-schema": "^4.0.2",
-    "ansi-styles": "^5.0.0",
-    "camelcase": "6",
-    "decamelize": "1.2.0",
     "js-tiktoken": "^1.0.12",
     "langsmith": "^0.3.64",
     "mustache": "^4.2.0",
-    "p-queue": "^6.6.2",
-    "p-retry": "^7.0.0",
+    "p-queue": "^9.0.1",
     "uuid": "^10.0.0",
     "zod": "^3.25.76 || ^4"
   },
@@ -47,10 +43,14 @@
     "@types/decamelize": "^1.2.0",
     "@types/mustache": "^4",
     "@types/uuid": "^10.0.0",
+    "ansi-styles": "^6.2.3",
+    "camelcase": "^9.0.0",
+    "decamelize": "^6.0.1",
     "dotenv": "^17.2.1",
     "dpdm": "^3.14.0",
     "eslint": "^9.34.0",
     "ml-matrix": "^6.10.4",
+    "p-retry": "^7.0.0",
     "prettier": "^2.8.3",
     "rimraf": "^5.0.1",
     "typescript": "~5.8.3",
@@ -843,4 +843,4 @@
     "outputs.js"
   ],
   "module": "./dist/index.js"
-}
+}

libs/langchain-core/src/callbacks/tests/callbacks.test.ts

@@ -242,6 +242,10 @@ test("CallbackManager Chat Message Handling", async () => {
       await llmCb.handleLLMEnd({ generations: [] });
     })
   );
+
+  // In case background mode is on while running this test
+  await awaitAllCallbacks();
+
   // Everything treated as llm in handler 1
   expect(handler1.llmStarts).toBe(1);
   expect(handler2.llmStarts).toBe(0);

libs/langchain-core/src/singletons/callbacks.ts

@@ -4,7 +4,7 @@ import PQueueMod from "p-queue";
 import { getGlobalAsyncLocalStorageInstance } from "./async_local_storage/globals.js";
 import { getDefaultLangChainClientSingleton } from "./tracer.js";
 
-let queue: typeof import("p-queue")["default"]["prototype"];
+let queue: (typeof PQueueMod)["prototype"];
 
 /**
  * Creates a queue using the p-queue library. The queue is configured to

libs/langchain-core/src/tracers/tests/__snapshots__/langchain_tracer.test.ts.snap

@@ -109,12 +109,15 @@ exports[`LangChainTracer payload snapshots for run create and update 3`] = `
   "inputs": {
     "input": "test input",
   },
+  "name": "RunnableLambda",
   "outputs": {
     "output": "processed: test input",
   },
   "parent_run_id": Any<String>,
   "reference_example_id": undefined,
+  "run_type": "chain",
   "session_name": Any<String>,
+  "start_time": Any<String>,
   "tags": [],
   "trace_id": Any<String>,
 }
@@ -141,12 +144,15 @@ exports[`LangChainTracer payload snapshots for run create and update 4`] = `
   "inputs": {
     "input": "test input",
   },
+  "name": "RunnableLambda",
   "outputs": {
     "output": "parent: processed: test input",
   },
   "parent_run_id": undefined,
   "reference_example_id": undefined,
+  "run_type": "chain",
   "session_name": Any<String>,
+  "start_time": Any<String>,
   "tags": [],
   "trace_id": Any<String>,
 }

libs/langchain-core/src/tracers/tests/langchain_tracer.test.ts

@@ -73,6 +73,7 @@ test("LangChainTracer payload snapshots for run create and update", async () =>
   expect(updatePayloads[0]).toMatchSnapshot({
     session_name: expect.any(String),
     dotted_order: expect.any(String),
+    start_time: expect.any(String),
     end_time: expect.any(Number),
     events: expect.arrayContaining([
       expect.objectContaining({
@@ -86,6 +87,7 @@ test("LangChainTracer payload snapshots for run create and update", async () =>
   expect(updatePayloads[1]).toMatchSnapshot({
     session_name: expect.any(String),
     dotted_order: expect.any(String),
+    start_time: expect.any(String),
     end_time: expect.any(Number),
     events: expect.arrayContaining([
       expect.objectContaining({

libs/langchain-core/src/utils/async_caller.ts

@@ -1,20 +1,8 @@
 import PQueueMod from "p-queue";
+import pRetry from "p-retry";
 
 import { getAbortSignalError } from "./signal.js";
 
-// p-retry is ESM-only, so we use dynamic import for CJS compatibility.
-// The module is cached after first import, so subsequent calls are essentially free.
-// This approach is recommended by the p-retry author for async contexts:
-// https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
-let pRetryModule: typeof import("p-retry") | null = null;
-
-async function getPRetry() {
-  if (!pRetryModule) {
-    pRetryModule = await import("p-retry");
-  }
-  return pRetryModule.default;
-}
-
 const STATUS_NO_RETRY = [
   400, // Bad Request
   401, // Unauthorized
@@ -119,7 +107,6 @@ export class AsyncCaller {
     callable: T,
     ...args: Parameters<T>
   ): Promise<Awaited<ReturnType<T>>> {
-    const pRetry = await getPRetry();
     return this.queue.add(
       () =>
         pRetry(

libs/langchain-core/tsdown.config.ts

@@ -7,6 +7,11 @@ import {
 } from "@langchain/build";
 
 export default getBuildConfig({
+  /**
+   * bundling these packages into the output for CJS compatibility
+   * they only need to be devDependencies, not runtime dependencies
+   */
+  noExternal: [`ansi-styles`, `camelcase`, `decamelize`, `p-retry`],
   entry: [
     "./src/index.ts",
     "./src/agents.ts",