#2216: Fix compile errors when using newer fmt version

Author: JacobDomagala

src/vt/rdma/rdma_common.h

@@ -120,7 +120,9 @@ static constexpr ByteType rdma_default_byte_size = sizeof(char);
 VT_FMT_NAMESPACE_BEGIN
 
 template <>
-struct formatter<::vt::rdma::Type> : formatter<std::string_view> {
+struct formatter<::vt::rdma::Type> {
+  constexpr auto parse(fmt::format_parse_context& ctx) { return ctx.begin(); }
+
   template <typename FormatContext>
   auto format(::vt::rdma::Type t, FormatContext& ctx) const {
     std::string_view name = "Unknown";
@@ -141,7 +143,8 @@ struct formatter<::vt::rdma::Type> : formatter<std::string_view> {
       name = fmt::format(
         "{}", static_cast<std::underlying_type_t<::vt::rdma::Type>>(t));
     }
-    return formatter<std::string_view>::format(name, ctx);
+
+    return fmt::format_to(ctx.out(), name);
   }
 };
 

src/vt/topos/index/dense/dense_array.h

@@ -160,14 +160,14 @@ static_assert(
 VT_FMT_NAMESPACE_BEGIN
 
 template <typename IndexType, ::vt::index::NumDimensionsType ndim>
-struct formatter<::vt::index::DenseIndexArray<IndexType, ndim>>
-  : formatter<std::string> {
+struct formatter<::vt::index::DenseIndexArray<IndexType, ndim>> {
+  constexpr auto parse(fmt::format_parse_context& ctx) { return ctx.begin(); }
+
   template <typename FormatContext>
   auto format(
     const ::vt::index::DenseIndexArray<IndexType, ndim>& idx,
-    FormatContext& ctx
-  ) const {
-    return formatter<std::string>::format(idx.toString(), ctx);
+    FormatContext& ctx) const {
+    return fmt::format_to(ctx.out(), idx.toString());
   }
 };
 

src/vt/vrt/collection/balance/temperedlb/criterion.h

@@ -96,8 +96,9 @@ struct Criterion {
 VT_FMT_NAMESPACE_BEGIN
 
 template <>
-struct formatter<::vt::vrt::collection::lb::CriterionEnum>
-  : formatter<std::string_view> {
+struct formatter<::vt::vrt::collection::lb::CriterionEnum> {
+  constexpr auto parse(fmt::format_parse_context& ctx) { return ctx.begin(); }
+
   template <typename FormatContext>
   auto format(::vt::vrt::collection::lb::CriterionEnum c, FormatContext& ctx) const {
     std::string_view name = "Unknown";
@@ -109,7 +110,7 @@ struct formatter<::vt::vrt::collection::lb::CriterionEnum>
       name = "ModifiedGrapevine";
       break;
     }
-    return formatter<string_view>::format(name, ctx);
+    return fmt::format_to(ctx.out(), name);
   }
 };
 

tests/unit/lb/test_lbargs_enum_conv.nompi.cc

@@ -150,7 +150,9 @@ TEST_F(TestLBArgsEnumConverter, test_enum_converter_config) {
 
 VT_FMT_NAMESPACE_BEGIN
   template <>
-  struct formatter<::vt::tests::unit::DummyEnum> : formatter<std::string_view> {
+  struct formatter<::vt::tests::unit::DummyEnum> {
+    constexpr auto parse(fmt::format_parse_context& ctx) { return ctx.begin(); }
+
     template <typename FormatContext>
     auto format(::vt::tests::unit::DummyEnum c, FormatContext& ctx) const {
       std::string_view name = "Unknown";
@@ -165,7 +167,7 @@ VT_FMT_NAMESPACE_BEGIN
         name = "Three";
         break;
       }
-      return formatter<string_view>::format(name, ctx);
+      return fmt::format_to(ctx.out(), name);
     }
   };
 VT_FMT_NAMESPACE_END