From 86741d645da005b2ed17e30aebdef7b6e02633de Mon Sep 17 00:00:00 2001
From: Benjamin Kietzman <bengilgit@gmail.com>
Date: Mon, 4 Nov 2024 11:53:42 -0600
Subject: [PATCH] Pack Struct::State a little with reordered is_constant

---
 cpp/src/arrow/status.cc         | 4 ++--
 cpp/src/arrow/status.h          | 2 +-
 cpp/src/arrow/status_internal.h | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/cpp/src/arrow/status.cc b/cpp/src/arrow/status.cc
index de2955de4619e..81f5f88e0f0d1 100644
--- a/cpp/src/arrow/status.cc
+++ b/cpp/src/arrow/status.cc
@@ -28,7 +28,7 @@ Status::Status(StatusCode code, const std::string& msg)
 
 Status::Status(StatusCode code, std::string msg, std::shared_ptr<StatusDetail> detail) {
   ARROW_CHECK_NE(code, StatusCode::OK) << "Cannot construct ok status with message";
-  state_ = new State{code, std::move(msg), std::move(detail)};
+  state_ = new State{code, /*is_constant=*/false, std::move(msg), std::move(detail)};
 }
 
 void Status::CopyFrom(const Status& s) {
@@ -165,7 +165,7 @@ void Status::AddContextLine(const char* filename, int line, const char* expr) {
   ss << "\n" << filename << ":" << line << "  " << expr;
   if (state_->is_constant) {
     // We can't add context lines to a StatusConstant's state, so copy it now
-    state_ = new State{code(), message(), detail()};
+    state_ = new State{code(), /*is_constant=*/false, message(), detail()};
   }
   const_cast<State*>(state_)->msg += ss.str();
 }
diff --git a/cpp/src/arrow/status.h b/cpp/src/arrow/status.h
index 45d61a63c4f57..a52a3600e434d 100644
--- a/cpp/src/arrow/status.h
+++ b/cpp/src/arrow/status.h
@@ -369,9 +369,9 @@ class ARROW_EXPORT [[nodiscard]] Status : public util::EqualityComparable<Status
  private:
   struct State {
     StatusCode code;
+    bool is_constant;
     std::string msg;
     std::shared_ptr<StatusDetail> detail;
-    bool is_constant = false;
   };
   // OK status has a `NULL` state_.  Otherwise, `state_` points to
   // a `State` structure containing the error code and message(s)
diff --git a/cpp/src/arrow/status_internal.h b/cpp/src/arrow/status_internal.h
index 77474e389533f..80e6cd2cd610f 100644
--- a/cpp/src/arrow/status_internal.h
+++ b/cpp/src/arrow/status_internal.h
@@ -26,7 +26,7 @@ class StatusConstant {
  public:
   StatusConstant(StatusCode code, std::string msg,
                  std::shared_ptr<StatusDetail> detail = nullptr)
-      : state_{code, std::move(msg), std::move(detail), /*is_constant=*/true} {
+      : state_{code, /*is_constant=*/true, std::move(msg), std::move(detail)} {
     ARROW_CHECK_NE(code, StatusCode::OK)
         << "StatusConstant is not intended for use with OK status codes";
   }