Fix calling chain.run() with memory (#1642)

langchain/src/chains/base.ts

@@ -82,13 +82,16 @@ export abstract class BaseChain extends BaseLangChain implements ChainInputs {
     input: any,
     callbacks?: Callbacks
   ): Promise<string> {
-    const isKeylessInput = this.inputKeys.length <= 1;
+    const inputKeys = this.inputKeys.filter(
+      (k) => !this.memory?.memoryKeys.includes(k) ?? true
+    );
+    const isKeylessInput = inputKeys.length <= 1;
     if (!isKeylessInput) {
       throw new Error(
         `Chain ${this._chainType()} expects multiple inputs, cannot use 'run' `
       );
     }
-    const values = this.inputKeys.length ? { [this.inputKeys[0]]: input } : {};
+    const values = inputKeys.length ? { [inputKeys[0]]: input } : {};
     const returnValues = await this.call(values, callbacks);
     const keys = Object.keys(returnValues);
 

langchain/src/chains/tests/llm_chain.int.test.ts

@@ -8,6 +8,7 @@ import {
 } from "../../prompts/index.js";
 import { LLMChain } from "../llm_chain.js";
 import { loadChain } from "../load.js";
+import { BufferMemory } from "../../memory/buffer_memory.js";
 
 test("Test OpenAI", async () => {
   const model = new OpenAI({ modelName: "text-ada-001" });
@@ -46,6 +47,21 @@ test("Test run method", async () => {
   console.log({ res });
 });
 
+test("Test run method", async () => {
+  const model = new OpenAI({ modelName: "text-ada-001" });
+  const prompt = new PromptTemplate({
+    template: "{history} Print {foo}",
+    inputVariables: ["foo", "history"],
+  });
+  const chain = new LLMChain({
+    prompt,
+    llm: model,
+    memory: new BufferMemory(),
+  });
+  const res = await chain.run("my favorite color");
+  console.log({ res });
+});
+
 test("Test apply", async () => {
   const model = new OpenAI({ modelName: "text-ada-001" });
   const prompt = new PromptTemplate({