From 1d5e727005e84a888a6c8accf1212ad273f0d6aa Mon Sep 17 00:00:00 2001
From: Le Roux Bodenstein <leroux.bodenstein@mongodb.com>
Date: Fri, 21 Nov 2025 11:07:09 +0000
Subject: [PATCH] warn when util.inspect() truncated output

---
 packages/cli-repl/src/format-output.ts | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/packages/cli-repl/src/format-output.ts b/packages/cli-repl/src/format-output.ts
index bd6971aa4a..0db60bd847 100644
--- a/packages/cli-repl/src/format-output.ts
+++ b/packages/cli-repl/src/format-output.ts
@@ -26,6 +26,7 @@ export type FormatOptions = {
   showStackTraces?: boolean;
   bugReportErrorMessageInfo?: string;
   allowControlCharacters?: boolean;
+  warnTruncatedOutput?: boolean;
 };
 
 // eslint-disable-next-line no-control-regex
@@ -160,7 +161,7 @@ Use db.getCollection('system.profile').find() to show raw profile entries.`,
     });
   }
 
-  return formatSimpleType(value, options);
+  return formatSimpleType(value, { ...options, warnTruncatedOutput: true });
 }
 
 function formatSimpleType(output: any, options: FormatOptions): string {
@@ -173,7 +174,19 @@ function formatSimpleType(output: any, options: FormatOptions): string {
   }
   if (typeof output === 'undefined') return '';
 
-  return inspect(output, options);
+  let result = inspect(output, options);
+  if (options.warnTruncatedOutput) {
+    if (
+      /(\d+ more item)|(\d+ more character)|(\[Object\])|(\[Array\])/.test(
+        result
+      )
+    ) {
+      result +=
+        '\nWarning: The output might be truncated.' +
+        '\nTo see more use util.inspect() with custom options or configure depth, maxArrayLength and maxStringLength config options.';
+    }
+  }
+  return result;
 }
 
 function formatCollections(