tuplet: fix bad code generation.

codeinred/tuplet#29

recipes/tuplet/all/conandata.yml

@@ -8,3 +8,8 @@ sources:
   "1.2.2":
     url: "https://github.com/codeinred/tuplet/archive/refs/tags/v1.2.2.tar.gz"
     sha256: "8605abf16f3ffcf87b0a5d81bc30f75b1fb478a5d747749fca31397e8705f8bc"
+patches:
+  "2.1.0":
+    - patch_file: "patches/0001-fix-workaround-cl-17.1-fold-expression-issues.patch"
+      patch_description: "fix bad code generation with VS2022 c++20, tuplet issue #29"
+      patch_type: "conan"

recipes/tuplet/all/conanfile.py

@@ -1,7 +1,7 @@
 from conan import ConanFile
 from conan.errors import ConanInvalidConfiguration
 from conan.tools.build import check_min_cppstd
-from conan.tools.files import copy, get
+from conan.tools.files import export_conandata_patches, apply_conandata_patches, copy, get
 from conan.tools.layout import basic_layout
 from conan.tools.scm import Version
 import os
@@ -41,6 +41,9 @@ def _compilers_minimum_version(self):
             "apple-clang": "12"
         }
 
+    def export_sources(self):
+        export_conandata_patches(self)
+
     def package_id(self):
         self.info.clear()
 
@@ -70,7 +73,7 @@ def source(self):
             destination=self.source_folder, strip_root=True)
 
     def build(self):
-        pass
+        apply_conandata_patches(self)
 
     def package(self):
         include_folder = os.path.join(self.source_folder, "include")

recipes/tuplet/all/patches/0001-fix-workaround-cl-17.1-fold-expression-issues.patch

@@ -0,0 +1,31 @@
+From b8a5bb75e44482eddc9bdfa04c7aed56d6d46b59 Mon Sep 17 00:00:00 2001
+From: Luke Elliott <[email protected]>
+Date: Sun, 12 Mar 2023 16:55:14 +0000
+Subject: [PATCH] fix: workaround cl 17.1 fold expression issues.
+
+#29
+---
+ include/tuplet/tuple.hpp | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/include/tuplet/tuple.hpp b/include/tuplet/tuple.hpp
+index 749d32a..f385e9f 100644
+--- a/include/tuplet/tuple.hpp
++++ b/include/tuplet/tuple.hpp
+@@ -895,9 +895,12 @@ namespace tuplet {
+
+         template <class U, class... B1, class... B2>
+         constexpr void _assign_tup(U&& u, type_list<B1...>, type_list<B2...>) {
++            // Not: (void(B1::value = static_cast<U&&>(u).identity_t<B2>::value), ...);
+             // See:
+             // https://developercommunity.visualstudio.com/t/fold-expressions-unreliable-in-171-with-c20/1676476
+-            (void(B1::value = static_cast<U&&>(u).identity_t<B2>::value), ...);
++            // https://github.com/codeinred/tuplet/issues/21
++            // https://github.com/codeinred/tuplet/issues/29
++            (void(B1::value = std::forward<identity_t<B2>>(u).value), ...);
+         }
+         template <class U, size_t... I>
+         constexpr void _assign_index_tup(U&& u, std::index_sequence<I...>) {
+-- 
+2.39.2.windows.1
+