AK: Add support for "debug only" formatters

These are formatters that can only be used with debug print
functions, such as dbgln(). Currently this is limited to
Formatter<ErrorOr<T>>. With this you can still debug log ErrorOr
values (good for debugging), but trying to use them in any
String::formatted() call will fail (which prevents .to_string()
errors with the new failable strings being ignored).

You make a formatter debug only by adding a constexpr method like:
static constexpr bool is_debug_only() { return true; }

3 files changed, 3 insertions, 3 deletions

diff --git a/Kernel/Bus/PCI/Device.h b/Kernel/Bus/PCI/Device.h
index 9c1d1fa92e..61a713b664 100644
--- a/Kernel/Bus/PCI/Device.h
+++ b/Kernel/Bus/PCI/Device.h
@@ -48,7 +48,7 @@ void dmesgln_pci(Device const& device, AK::CheckedFormatString<Parameters...>&&
         return;
     if (builder.try_append(fmt.view()).is_error())
         return;
-    AK::VariadicFormatParams variadic_format_params { device.device_name(), device.pci_address(), parameters... };
+    AK::VariadicFormatParams<AK::AllowDebugOnlyFormatters::Yes, StringView, Address, Parameters...> variadic_format_params { device.device_name(), device.pci_address(), parameters... };
     vdmesgln(builder.string_view(), variadic_format_params);
 }
 
diff --git a/Kernel/KBufferBuilder.h b/Kernel/KBufferBuilder.h
index 426b7c8d9b..f5e6d10f48 100644
--- a/Kernel/KBufferBuilder.h
+++ b/Kernel/KBufferBuilder.h
@@ -37,7 +37,7 @@ public:
     {
         // FIXME: This really not ideal, but vformat expects StringBuilder.
         StringBuilder builder;
-        AK::VariadicFormatParams variadic_format_params { parameters... };
+        AK::VariadicFormatParams<AK::AllowDebugOnlyFormatters::No, Parameters...> variadic_format_params { parameters... };
         TRY(vformat(builder, fmtstr.view(), variadic_format_params));
         return append_bytes(builder.string_view().bytes());
     }
diff --git a/Kernel/KString.h b/Kernel/KString.h
index 2639f9617b..7905936dbe 100644
--- a/Kernel/KString.h
+++ b/Kernel/KString.h
@@ -26,7 +26,7 @@ public:
     template<typename... Parameters>
     [[nodiscard]] static ErrorOr<NonnullOwnPtr<KString>> formatted(CheckedFormatString<Parameters...>&& fmtstr, Parameters const&... parameters)
     {
-        AK::VariadicFormatParams variadic_format_parameters { parameters... };
+        AK::VariadicFormatParams<AK::AllowDebugOnlyFormatters::No, Parameters...> variadic_format_parameters { parameters... };
         return vformatted(fmtstr.view(), variadic_format_parameters);
     }