From e81b4f88bc225202f87e92ab7efa3825a065fce8 Mon Sep 17 00:00:00 2001
From: "Andrei.Ovcharenko" <a@krot.name>
Date: Sun, 18 Oct 2026 08:39:45 +0300
Subject: [PATCH] fix: normalize a leading UTF-8 BOM before CSV conversion

---
 src/MarkdownTableCore.cpp                     |  2 +-
 test-fixtures/markdown-table-core-golden.json | 35 +++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/MarkdownTableCore.cpp b/src/MarkdownTableCore.cpp
index 63cca6c..2c4867d 100644
--- a/src/MarkdownTableCore.cpp
+++ b/src/MarkdownTableCore.cpp
@@ -2824,7 +2824,7 @@ EditResult convertDelimitedToTable(const std::string &text)
 {
 	EditResult result;
 	// Tabs at the edges delimit empty TSV cells and must reach the parser.
-	const std::string &value = text;
+	const std::string value = text.compare(0, 3, "\xEF\xBB\xBF") == 0 ? text.substr(3) : text;
 	const char delimiter = detectDelimiter(value);
 	if (!hasDelimitedStructure(value, delimiter))
 	{
diff --git a/test-fixtures/markdown-table-core-golden.json b/test-fixtures/markdown-table-core-golden.json
index 284c7fe..7b8d08b 100644
--- a/test-fixtures/markdown-table-core-golden.json
+++ b/test-fixtures/markdown-table-core-golden.json
@@ -1,6 +1,41 @@
 {
   "schemaVersion": 2,
   "conversion": [
+    {
+      "name": "leading bom quoted csv",
+      "input": "\uFEFF\"Name\",\"City\"\n\"Bob\",\"Paris\"",
+      "lines": ["| Name | City  |", "| ---- | ----- |", "| Bob  | Paris |"]
+    },
+    {
+      "name": "leading bom quoted tsv crlf",
+      "input": "\uFEFF\"Name\"\t\"City\"\r\n\"Bob\"\t\"Paris\"",
+      "lines": ["| Name | City  |", "| ---- | ----- |", "| Bob  | Paris |"]
+    },
+    {
+      "name": "leading bom multiline quoted csv header",
+      "input": "\uFEFF\"First\nName\",City\nBob,Paris",
+      "lines": ["| First Name | City  |", "| ---------- | ----- |", "| Bob        | Paris |"]
+    },
+    {
+      "name": "leading bom empty tsv edge cells",
+      "input": "\uFEFF\tName\t\n\tBob\t",
+      "lines": ["|     | Name |     |", "| --- | ---- | --- |", "|     | Bob  |     |"]
+    },
+    {
+      "name": "leading bom preserves internal bom",
+      "input": "\uFEFFName,City\nBo\uFEFFb,Paris",
+      "lines": ["| Name | City  |", "| ---- | ----- |", "| Bo\uFEFFb  | Paris |"]
+    },
+    {
+      "name": "leading bom quoted csv tab is data",
+      "input": "\uFEFF\"Name\tAlias\",City\nBob,Paris",
+      "lines": ["| Name\tAlias | City  |", "| ---------- | ----- |", "| Bob        | Paris |"]
+    },
+    {
+      "name": "leading bom escaped pipe contract",
+      "input": "\uFEFFName,Note\nBob,\"a|b\\|c\"",
+      "lines": ["| Name | Note    |", "| ---- | ------- |", "| Bob  | a\\|b\\|c |"]
+    },
     {
       "name": "quoted tabs in later records preserve established tsv",
       "input": "Title, notes\nA\tfoo\nB\tbar\n\t\"x\ty\"",