From 5b776e85e79639d132e8d016e28bc8099319b2ed Mon Sep 17 00:00:00 2001
From: Ivan Koptiev <ivan@firebolt.io>
Date: Tue, 30 Jun 2026 15:25:46 +0300
Subject: [PATCH] fix(thrift): add TEnumIterator::operator== for libc++ 22

libc++ >= 19 implements std::map's range constructor with `first == last`. arrow's vendored
thrift TEnumIterator only declared operator!=, so std::map<int,const char*>(TEnumIterator,...)
in the generated parquet_types.cpp failed to compile under the LLVM 22 toolchain. Add the
matching operator==.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 third_party/thrift/lib/cpp/src/thrift/Thrift.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/third_party/thrift/lib/cpp/src/thrift/Thrift.h b/third_party/thrift/lib/cpp/src/thrift/Thrift.h
index 8a86b748acfa..359faa304768 100644
--- a/third_party/thrift/lib/cpp/src/thrift/Thrift.h
+++ b/third_party/thrift/lib/cpp/src/thrift/Thrift.h
@@ -61,6 +61,15 @@ class TEnumIterator {
     return (ii_ != n_);
   }
 
+  // libc++ >= 19 implements std::map's range constructor with `first == last`; TEnumIterator only
+  // declared operator!=, so std::map<int,const char*>(TEnumIterator,...) failed to compile under the
+  // LLVM 22 toolchain ("invalid operands to binary expression"). Provide the matching ==.
+  bool operator==(const TEnumIterator& end) const {
+    THRIFT_UNUSED_VARIABLE(end);
+    assert(end.n_ == -1);
+    return (ii_ == n_);
+  }
+
   std::pair<int, const char*> operator*() const { return std::make_pair(enums_[ii_], names_[ii_]); }
 
 private: