From 6133bb6979684ac1f33e4c34826d5f414ed9b014 Mon Sep 17 00:00:00 2001
From: Thomas Boucher <thomas.boucher@gopigment.com>
Date: Wed, 18 Jun 2025 11:50:31 +0200
Subject: [PATCH] Avoid allocating objects for invalid fields when no "bad
 data" callback defined.

---
 src/CsvHelper/CsvParser.cs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/CsvHelper/CsvParser.cs b/src/CsvHelper/CsvParser.cs
index 83ad97b22..495ce8475 100644
--- a/src/CsvHelper/CsvParser.cs
+++ b/src/CsvHelper/CsvParser.cs
@@ -944,8 +944,13 @@ protected ProcessedField ProcessRFC4180BadField(int start, int length)
 	{
 		// If field is already known to be bad, different rules can be applied.
 
-		var args = new BadDataFoundArgs(new string(buffer, start, length), RawRecord, Context);
-		badDataFound?.Invoke(args);
+		if (badDataFound is not null)
+		{
+			// Note on performance: accessing RawRecord allocates a new string with the entire row.
+			// It can be costly overall when lots of fields are invalid.
+			var args = new BadDataFoundArgs(new string(buffer, start, length), RawRecord, Context);
+			badDataFound.Invoke(args);
+		}
 
 		var newStart = start;
 		var newLength = length;