fix: resolve Clang-20 and MSVC compilation errors

column_field.hpp (Clang-20):
- Replace captureless lambda in tag_to_column_name consteval function
  with a ternary expression. Clang-20 correctly rejects references to
  local constexpr variables inside a [] lambda; GCC was permissive.
  Ternary preserves identical min-of-two-finds logic without any capture.

test_dql_extensions.cpp (MSVC):
- Qualify ds_mysql::round and ds_mysql::format with explicit namespace
  in the round/format alias test (line 297). MSVC pulls ::round from
  <cmath> into the global namespace, making unqualified 'round' ambiguous
  when 'using namespace ds_mysql' is also active.

ci.yml (Clang job):
- Use clang-20 instead of clang-18. clang-18 has a known bug where
  __is_base_of returns false for column_field<Tag,T> derived from
  column_field_tag via a base<T> partial specialization; clang-20 is
  correct. Ubuntu noble 24.04 ships clang-20 in its standard repos.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Pierre-Luc Gagné

.github/workflows/ci.yml

@@ -89,14 +89,14 @@ jobs:
           echo 'deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ noble main' \
             | sudo tee /etc/apt/sources.list.d/kitware.list
           sudo apt-get update -q
-          sudo apt-get install -y cmake ninja-build clang-18 \
+          sudo apt-get install -y cmake ninja-build clang-20 \
             libmysqlclient-dev pkg-config
 
       - name: Configure
         run: cmake --preset release -DSKIP_DOCKER_MANAGEMENT=ON -DBUILD_INTEGRATION_TESTS=OFF -DBUILD_EXAMPLES=OFF
         env:
-          CXX: clang++-18
-          CC: clang-18
+          CXX: clang++-20
+          CC: clang-20
 
       - name: Build
         run: cmake --build build -j4

lib/include/ds_mysql/column_field.hpp

@@ -63,16 +63,9 @@ consteval std::string_view tag_to_column_name() noexcept {
     constexpr auto start = key_pos + key.size();
     constexpr auto end1 = sig.find(';', start);
     constexpr auto end2 = sig.find(']', start);
-    constexpr auto end = [] {
-        if constexpr (end1 != npos && end2 != npos) {
-            return (end1 < end2) ? end1 : end2;
-        } else if constexpr (end1 != npos) {
-            return end1;
-        } else if constexpr (end2 != npos) {
-            return end2;
-        }
-        return npos;
-    }();
+    constexpr auto end = (end1 != npos && end2 != npos) ? ((end1 < end2) ? end1 : end2) :
+                         (end1 != npos) ? end1 :
+                         (end2 != npos) ? end2 : npos;
     if constexpr (end == npos || end <= start) {
         static_assert(dependent_false_v<Tag>, "Failed to locate end of Tag name in compiler function signature");
         return {};

tests/unit/test_dql_extensions.cpp

@@ -294,7 +294,9 @@ suite<"DQL Scalar Functions"> dql_scalar_functions_suite = [] {
 
     "round/format aliases — generate expected SQL"_test = [] {
         auto const sql =
-            select<round<product::price_val, 2>, format<product::price_val, 2>>().from<product>().build_sql();
+            select<ds_mysql::round<product::price_val, 2>, ds_mysql::format<product::price_val, 2>>()
+                .from<product>()
+                .build_sql();
         expect(sql == "SELECT ROUND(price_val, 2), FORMAT(price_val, 2) FROM product"s) << sql;
     };