Merge pull request #1716 from evoskuil/master

evoskuil · web-flow · commit 98cacd6b44fc · 2025-09-19T00:59:05.000-04:00
Fix: don't consume limit in byte_reader::peek, test.
diff --git a/include/bitcoin/system/impl/stream/streamers/byte_reader.ipp b/include/bitcoin/system/impl/stream/streamers/byte_reader.ipp
@@ -655,8 +655,11 @@ byte_allocator& byte_reader<IStream>::get_allocator() const NOEXCEPT
 template <typename IStream>
 uint8_t byte_reader<IStream>::do_peek_byte() NOEXCEPT
 {
-    if (limiter(one))
+    if (is_zero(remaining_))
+    {
+        invalid();
         return pad();
+    }
 
     // This sets eofbit (or badbit) on empty and eofbit if otherwise at end.
     // eofbit does not cause !!eofbit == true, but badbit does, so we validate
diff --git a/test/stream/streamers/byte_reader.cpp b/test/stream/streamers/byte_reader.cpp
@@ -467,6 +467,11 @@ BOOST_AUTO_TEST_CASE(byte_reader__set_limit__set_position_forward_peek__limited)
     reader.set_position(3);
     BOOST_REQUIRE(!reader.is_exhausted());
 
+    // Peek does not consume limit (as verified by subsequent reads).
+    BOOST_REQUIRE_EQUAL(reader.peek_byte(), 'd');
+    BOOST_REQUIRE_EQUAL(reader.peek_byte(), 'd');
+    BOOST_REQUIRE_EQUAL(reader.peek_byte(), 'd');
+
     // Read to limit and verify.
     BOOST_REQUIRE_EQUAL(reader.get_read_position(), 3u);
     BOOST_REQUIRE_EQUAL(reader.read_byte(), 'd');
