String buffer fix

CMakeLists.txt

@@ -61,8 +61,8 @@ include(cmake/Installation.cmake)
 if(STRING_LENGTH)
   if(STRING_LENGTH GREATER_EQUAL 100)
     message(STATUS "Max calliper label length is ${STRING_LENGTH}")
-    target_compile_definitions(${CMAKE_PROJECT_NAME} INTERFACE
-      PROF_STRING_BUFFER_LENGTH=${STRING_LENGTH})
+    target_compile_definitions(${CMAKE_PROJECT_NAME} PUBLIC
+      "PROF_STRING_BUFFER_LENGTH=${STRING_LENGTH}")
   else()
     message(WARNING "Max calliper label length is too small - using 100")
   endif()

CONTRIBUTORS.md

@@ -5,4 +5,5 @@
 | andrewcoughtrie | Andrew Coughtrie | Met Office  | 2026-03-05 |
 | mo-marqh        | mark Hedley      | Met Office  | 2026-03-10 |
 | oakleybrunt     | Oakley Brunt     | Met Office  | 2026-03-09 |
-| EdHone          | Ed Hone          | Met Office  | 2026-03-20 |
+| EdHone          | Ed Hone          | Met Office  | 2026-03-20 |
+| t00sa           | Sam Clarke-Green | Met Office  | 2026-03-26 |

src/c++/hashtable.cpp

@@ -13,6 +13,7 @@
 #include <cstddef>
 #include <cstring>
 #include <iterator>
+#include <sstream>
 
 /**
  * @brief Hashtable constructor
@@ -68,7 +69,11 @@ size_t meto::HashTable::compute_hash(std::string_view region_name, int tid) {
   new_chars.fill('\0');
 
   if (region_name.length() + num_extra_bytes > new_chars.size()) {
-    error_handler("Internal error: character buffer exhausted.", EXIT_FAILURE);
+    std::stringstream message;
+    message << "Vernier internal error: region name too long ("
+            << region_name.length() << " > "
+            << new_chars.size() - num_extra_bytes << ")";
+    error_handler(message.str(), EXIT_FAILURE);
   }
 
   // Get iterator to the start of the string buffer.

tests/unit_tests/c++/test_hashtable.cpp

@@ -15,6 +15,7 @@
 using ::testing::AllOf;
 using ::testing::An;
 using ::testing::Gt;
+using ::testing::HasSubstr;
 
 int const tid = 0;
 std::string tid_str(std::to_string(tid));
@@ -127,7 +128,7 @@ TEST(HashTableTest, NameLengthTest) {
   meto::vernier.init();
 
   EXPECT_EXIT(meto::vernier.start(label), testing::ExitedWithCode(1),
-              "Internal error: character buffer exhausted.");
+              HasSubstr("Vernier internal error: region name too long"));
 
   meto::vernier.finalize();
 }