From f52da8e8e10fe19e9a86ff725310cebb5a6dcb1a Mon Sep 17 00:00:00 2001
From: fhgffy <102001626+fhgffy@users.noreply.github.com>
Date: Fri, 9 Oct 2026 08:28:40 +0800
Subject: [PATCH] Reject trailing characters when parsing rfl::Timestamp

strptime() stops at the end of the format and returns a pointer to
whatever is left, but only a NULL result was treated as an error, so
"1987-04-19T10:00:00" was accepted for "%Y-%m-%d" and the rest was
silently dropped. Require the whole string to be consumed.

The Windows fallback also returned _s + tellg() when the stream hit EOF,
where tellg() is -1; return the end of the string in that case, as
ParserTimePoint already does.
---
 include/rfl/Timestamp.hpp     | 10 ++++++++--
 tests/json/test_timestamp.cpp |  9 +++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/rfl/Timestamp.hpp b/include/rfl/Timestamp.hpp
index 5c15122b1..a940e0fcb 100644
--- a/include/rfl/Timestamp.hpp
+++ b/include/rfl/Timestamp.hpp
@@ -1,6 +1,7 @@
 #ifndef RFL_TIMESTAMP_HPP_
 #define RFL_TIMESTAMP_HPP_
 
+#include <cstring>
 #include <ctime>
 #include <iomanip>
 #include <sstream>
@@ -35,7 +36,7 @@ class Timestamp {
   /// @throws std::runtime_error if the string doesn't match the format
   Timestamp(const char* _str) : tm_(std::tm{}) {
     const auto r = strptime(_str, _format.str().c_str(), &tm_);
-    if (r == NULL) {
+    if (r == NULL || *r != '\0') {
       throw std::runtime_error("String '" + std::string(_str) +
                                "' did not match format '" + Format().str() +
                                "'.");
@@ -169,7 +170,12 @@ class Timestamp {
     if (input.fail()) {
       return NULL;
     }
-    return (char*)(_s + input.tellg());
+    const auto pos = input.tellg();
+    if (pos == std::streampos(-1)) {
+      // The stream reached EOF, so all of the input was consumed.
+      return (char*)(_s + std::strlen(_s));
+    }
+    return (char*)(_s + static_cast<std::ptrdiff_t>(pos));
   }
 #endif
 
diff --git a/tests/json/test_timestamp.cpp b/tests/json/test_timestamp.cpp
index 0c91fb744..f4a237a5d 100644
--- a/tests/json/test_timestamp.cpp
+++ b/tests/json/test_timestamp.cpp
@@ -25,4 +25,13 @@ TEST(json, test_timestamp) {
       bart,
       R"({"firstName":"Bart","lastName":"Simpson","birthday":"1987-04-19"})");
 }
+
+TEST(json, test_timestamp_trailing_characters) {
+  EXPECT_TRUE(!TS::from_string("1987-04-19T10:00:00"));
+  EXPECT_TRUE(!TS::from_string("1987-04-19x"));
+
+  const auto res = rfl::json::read<Person>(
+      R"({"firstName":"Bart","lastName":"Simpson","birthday":"1987-04-19x"})");
+  EXPECT_TRUE(!res);
+}
 }  // namespace test_timestamp