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

Author: addaleax

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

@@ -47,7 +47,10 @@ import type { FormatOptions } from './format-output';
 import { markTime } from './startup-timing';
 import type { Context } from 'vm';
 import { Script, createContext, runInContext } from 'vm';
-import { installPasteSupport } from './repl-paste-support';
+import {
+  addReplEventForEvalReady,
+  installPasteSupport,
+} from './repl-paste-support';
 import util from 'util';
 
 declare const __non_webpack_require__: any;
@@ -260,7 +263,7 @@ class MongoshNodeRepl implements EvaluationListener {
       repl = asyncRepl.start({
         // 'repl' is not supported in startup snapshots yet.
         // eslint-disable-next-line @typescript-eslint/no-var-requires
-        start: require('pretty-repl').start,
+        //start: require('pretty-repl').start,
         input: this.lineByLineInput,
         output: this.output,
         prompt: '',
@@ -521,15 +524,11 @@ 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();
-    };
+    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

@@ -65,3 +65,36 @@ export function installPasteSupport(repl: REPLServer): string {
   });
   return onEnd;
 }
+
+// Not related to paste support, but rather for integrating with the MongoshNodeRepl's
+// line-by-line input handling.
+export function addReplEventForEvalReady(
+  repl: REPLServer,
+  before: () => boolean,
+  after: () => void
+): void {
+  const wrapMethodWithLineByLineInputNextLine = (
+    repl: REPLServer,
+    key: keyof REPLServer
+  ) => {
+    const originalMethod = repl[key].bind(repl);
+    if (!originalMethod) return;
+    (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);
+}