fix(cli-repl): account for Node.js 24 multi-line REPL handling update MONGOSH-2233 (#2482)

Author: addaleax

packages/cli-repl/src/async-repl.ts

@@ -5,7 +5,7 @@ import type { ReadLineOptions } from 'readline';
 import type { ReplOptions, REPLServer } from 'repl';
 import type { start as originalStart } from 'repl';
 import { promisify } from 'util';
-import type { KeypressKey } from './repl-paste-support';
+import { prototypeChain, type KeypressKey } from './repl-paste-support';
 
 // Utility, inverse of Readonly<T>
 type Mutable<T> = {
@@ -407,3 +407,39 @@ function wrapPauseInput<Args extends any[], Ret>(
     }
   };
 }
+
+// Not related to paste support, but rather for integrating with the MongoshNodeRepl's
+// line-by-line input handling. Calling this methods adds hooks to `repl` that are called
+// when the REPL is ready to evaluate further input. Eventually, like the other code
+// in this file, we should upstream this into Node.js core and/or evaluate the need for
+// it entirely.
+export function addReplEventForEvalReady(
+  repl: REPLServer,
+  before: () => boolean,
+  after: () => void
+): void {
+  const wrapMethodWithLineByLineInputNextLine = (
+    repl: REPLServer,
+    key: keyof REPLServer
+  ) => {
+    if (!repl[key]) return;
+    const originalMethod = repl[key].bind(repl);
+    (repl as any)[key] = (...args: any[]) => {
+      if (!before()) {
+        return;
+      }
+      const result = originalMethod(...args);
+      after();
+      return result;
+    };
+  };
+  // https://github.com/nodejs/node/blob/88f4cef8b96b2bb9d4a92f6848ce4d63a82879a8/lib/internal/readline/interface.js#L954
+  // added in https://github.com/nodejs/node/commit/96be7836d794509dd455e66d91c2975419feed64
+  // handles newlines inside multi-line input and replaces `.displayPrompt()` which was
+  // previously used to print the prompt for multi-line input.
+  const addNewLineOnTTYKey = [...prototypeChain(repl)]
+    .flatMap((proto) => Object.getOwnPropertySymbols(proto))
+    .find((s) => String(s).includes('(_addNewLineOnTTY)')) as keyof REPLServer;
+  wrapMethodWithLineByLineInputNextLine(repl, 'displayPrompt');
+  wrapMethodWithLineByLineInputNextLine(repl, addNewLineOnTTYKey);
+}

packages/cli-repl/src/mongosh-repl.ts

@@ -521,15 +521,11 @@ class MongoshNodeRepl implements EvaluationListener {
     // This is used below for multiline history manipulation.
     let originalHistory: string[] | null = null;
 
-    const originalDisplayPrompt = repl.displayPrompt.bind(repl);
-
-    repl.displayPrompt = (...args: any[]) => {
-      if (!this.started) {
-        return;
-      }
-      originalDisplayPrompt(...args);
-      this.lineByLineInput.nextLine();
-    };
+    asyncRepl.addReplEventForEvalReady(
+      repl,
+      () => !!this.started,
+      () => this.lineByLineInput.nextLine()
+    );
 
     if (repl.commands.editor) {
       const originalEditorAction = repl.commands.editor.action.bind(repl);

packages/cli-repl/src/repl-paste-support.ts

@@ -11,7 +11,7 @@ export type KeypressKey = {
   code?: string;
 };
 
-function* prototypeChain(obj: unknown): Iterable<unknown> {
+export function* prototypeChain(obj: unknown): Iterable<unknown> {
   if (!obj) return;
   yield obj;
   yield* prototypeChain(Object.getPrototypeOf(obj));

packages/cli-repl/src/smoke-tests.ts

@@ -88,6 +88,7 @@ export async function runSmokeTests({
     tags,
     input,
     output,
+    env,
     testArgs,
     includeStderr,
     exitCode,
@@ -120,6 +121,19 @@ export async function runSmokeTests({
       exitCode: 0,
       perfTestIterations: 0,
     },
+    {
+      // Regression test for MONGOSH-2233, included here because multiline support is a bit
+      // more fragile when it comes to newer Node.js releases and these are the only tests
+      // that run as part of the homebrew setup.
+      name: 'print_multiline_terminal',
+      input: ['{', 'print("He" + "llo" +', '" Wor" + "ld!")', '}'],
+      env: { MONGOSH_FORCE_TERMINAL: 'true' },
+      output: /Hello World!/,
+      includeStderr: false,
+      testArgs: ['--nodb'],
+      exitCode: 0,
+      perfTestIterations: 0,
+    },
     {
       name: 'eval_nodb_print_plainvm',
       input: '',
@@ -313,7 +327,11 @@ export async function runSmokeTests({
           os.tmpdir(),
           `mongosh_smoke_test_${name}_${Date.now()}.js`
         );
-        await fs.writeFile(tmpfile, input, { mode: 0o600, flag: 'wx' });
+        await fs.writeFile(
+          tmpfile,
+          Array.isArray(input) ? input.join('\n') : input,
+          { mode: 0o600, flag: 'wx' }
+        );
         cleanup.unshift(async () => await fs.unlink(tmpfile));
         testArgs[index] = arg.replace('$INPUT_AS_FILE', tmpfile);
         actualInput = '';
@@ -326,6 +344,7 @@ export async function runSmokeTests({
       args: [...args, ...testArgs],
       input: actualInput,
       output,
+      env,
       includeStderr,
       exitCode,
       printSuccessResults: !wantPerformanceTesting,
@@ -377,6 +396,7 @@ async function runSmokeTest({
   name,
   executable,
   args,
+  env,
   input,
   output,
   exitCode,
@@ -386,7 +406,8 @@ async function runSmokeTest({
   name: string;
   executable: string;
   args: string[];
-  input: string;
+  env?: Record<string, string | undefined>;
+  input: string | string[];
   output: RegExp;
   exitCode?: number;
   includeStderr?: boolean;
@@ -398,6 +419,7 @@ async function runSmokeTest({
   const { spawn } = require('child_process') as typeof import('child_process');
   const proc = spawn(executable, [...args], {
     stdio: 'pipe',
+    env: { ...process.env, ...env },
   });
   let stdout = '';
   let stderr = '';
@@ -407,7 +429,14 @@ async function runSmokeTest({
   proc.stderr?.setEncoding('utf8').on('data', (chunk) => {
     stderr += chunk;
   });
-  proc.stdin!.end(input);
+  if (Array.isArray(input)) {
+    for (const chunk of input) {
+      proc.stdin!.write(chunk + '\n');
+    }
+    proc.stdin!.end();
+  } else {
+    proc.stdin!.end(input);
+  }
   const [[actualExitCode]] = await Promise.all([
     once(proc, 'exit'),
     once(proc.stdout!, 'end'),