From 6c88694a2943b7c1d5ca5c9a5c5dd1738a69c36b Mon Sep 17 00:00:00 2001
From: Bronek Kozicki <brok@incorrekt.com>
Date: Mon, 30 Oct 2023 18:13:25 +0000
Subject: [PATCH] fix: remove include <ranges> (#4788)

Remove dependency on `<ranges>` header, since it is not implemented by
all compilers which we want to support.

This code change only affects unit tests.

Resolve https://github.com/XRPLF/rippled/issues/4787
---
 src/test/jtx/TestHelpers.h | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/test/jtx/TestHelpers.h b/src/test/jtx/TestHelpers.h
index 2bee47a6411..b065cec470a 100644
--- a/src/test/jtx/TestHelpers.h
+++ b/src/test/jtx/TestHelpers.h
@@ -27,17 +27,25 @@
 #include <ripple/protocol/jss.h>
 #include <test/jtx/Env.h>
 
-#include <ranges>
+#include <vector>
 
 namespace ripple {
 namespace test {
 namespace jtx {
 
-// Helper to make vector from iterable
+// TODO We only need this long "requires" clause as polyfill, for C++20
+// implementations which are missing <ranges> header. Replace with
+// `std::ranges::range<Input>`, and accordingly use std::ranges::begin/end
+// when we have moved to better compilers.
+template <typename Input>
 auto
-make_vector(auto const& input) requires std::ranges::range<decltype(input)>
+make_vector(Input const& input) requires requires(Input& v)
 {
-    return std::vector(std::ranges::begin(input), std::ranges::end(input));
+    std::begin(v);
+    std::end(v);
+}
+{
+    return std::vector(std::begin(input), std::end(input));
 }
 
 // Functions used in debugging