From 9e45671c8acfcf0c7da9807adeef689be7fe70bf Mon Sep 17 00:00:00 2001
From: Hyukjin Kwon <gurwls223@apache.org>
Date: Mon, 29 Dec 2025 18:38:17 +0900
Subject: [PATCH] [C++] Fix ToStringWithoutContextLines to check for :\d+
 pattern before removing lines

---
 cpp/src/arrow/status.cc      | 12 ++++++++++--
 cpp/src/arrow/status_test.cc | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/cpp/src/arrow/status.cc b/cpp/src/arrow/status.cc
index 55ce3fb78d2..b97a9e3de08 100644
--- a/cpp/src/arrow/status.cc
+++ b/cpp/src/arrow/status.cc
@@ -13,6 +13,7 @@
 #include "arrow/status.h"
 
 #include <cassert>
+#include <cctype>
 #include <cstdlib>
 #include <iostream>
 #ifdef ARROW_EXTRA_ERROR_CONTEXT
@@ -131,8 +132,15 @@ std::string Status::ToStringWithoutContextLines() const {
     if (last_new_line_position == std::string::npos) {
       break;
     }
-    // TODO: We may want to check /:\d+ /
-    if (message.find(":", last_new_line_position) == std::string::npos) {
+    // Check for the pattern ":\d+" (colon followed by digits) to identify
+    // context lines in the format "filename:line  expr"
+    auto colon_position = message.find(":", last_new_line_position);
+    if (colon_position == std::string::npos) {
+      break;
+    }
+    // Verify that the colon is followed by at least one digit
+    if (colon_position + 1 >= message.size() ||
+        !std::isdigit(static_cast<unsigned char>(message[colon_position + 1]))) {
       break;
     }
     message = message.substr(0, last_new_line_position);
diff --git a/cpp/src/arrow/status_test.cc b/cpp/src/arrow/status_test.cc
index 39a52bd2bad..b0af683a55c 100644
--- a/cpp/src/arrow/status_test.cc
+++ b/cpp/src/arrow/status_test.cc
@@ -342,4 +342,23 @@ TEST(StatusTest, ReturnIfNotOk) {
   ASSERT_EQ(StripContext(st.message()), "StatusLike: 43");
 }
 
+#ifdef ARROW_EXTRA_ERROR_CONTEXT
+TEST(StatusTest, ToStringWithoutContextLines) {
+  Status status = Status::IOError("base error");
+  status.AddContextLine("file1.cc", 42, "expr");
+  status.AddContextLine("file2.cc", 100, "expr");
+
+  ASSERT_EQ(status.ToStringWithoutContextLines(), "IOError: base error");
+
+  Status status2(StatusCode::Invalid,
+                 "Error message\nThis line has: a colon but no digits");
+  status2.AddContextLine("file.cc", 20, "expr");
+
+  std::string result = status2.ToStringWithoutContextLines();
+  ASSERT_EQ(result.find("file.cc:20"), std::string::npos);
+  ASSERT_NE(result.find("This line has: a colon but no digits"), std::string::npos);
+  ASSERT_NE(result.find("Error message"), std::string::npos);
+}
+#endif
+
 }  // namespace arrow