(arrow) branch main updated: GH-49287: [C++][R] Clean up any other C++20 partial compatibility issues (#49223)

[thisisnic]

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thisisnic pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow.git


The following commit(s) were added to refs/heads/main by this push:
     new b5eb42e765 GH-49287: [C++][R] Clean up any other C++20 partial 
compatibility issues (#49223)
b5eb42e765 is described below

commit b5eb42e7658c3cbd05cfc673297bf4a7e46da574
Author: Jonathan Keane <jke...@gmail.com>
AuthorDate: Wed Feb 18 07:30:45 2026 -0600

    GH-49287: [C++][R] Clean up any other C++20 partial compatibility issues 
(#49223)
    
    Now that we have CI for it, check on other issues with C++20 compatibility 
on CRAN. I know that the code in #49105 is likely problematic
    
    Resolves: #49287
    
    ### Rationale for this change
    
    ### What changes are included in this PR?
    
    ### Are these changes tested?
    
    ### Are there any user-facing changes?
    * GitHub Issue: #49287
    
    Authored-by: Jonathan Keane <jke...@gmail.com>
    Signed-off-by: Nic Crane <thisis...@gmail.com>
---
 cpp/src/arrow/sparse_tensor.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/cpp/src/arrow/sparse_tensor.cc b/cpp/src/arrow/sparse_tensor.cc
index 477fa2f765..0852a0cdb8 100644
--- a/cpp/src/arrow/sparse_tensor.cc
+++ b/cpp/src/arrow/sparse_tensor.cc
@@ -406,9 +406,19 @@ std::string SparseCSFIndex::ToString() const { return 
std::string("SparseCSFInde
 
 bool SparseCSFIndex::Equals(const SparseCSFIndex& other) const {
   auto eq = [](const auto& a, const auto& b) { return a->Equals(*b); };
+// TODO: remove the use of std::equal when we no longer have partial C++20 
support with
+// CRAN.
+#if defined(__cpp_lib_ranges) && __cpp_lib_ranges >= 201911L
   return axis_order() == other.axis_order() &&
          std::ranges::equal(indices(), other.indices(), eq) &&
          std::ranges::equal(indptr(), other.indptr(), eq);
+#else
+  return axis_order() == other.axis_order() &&
+         std::equal(indices().begin(), indices().end(), 
other.indices().begin(),
+                    other.indices().end(), eq) &&
+         std::equal(indptr().begin(), indptr().end(), other.indptr().begin(),
+                    other.indptr().end(), eq);
+#endif
 }
 
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