From d552fa556077f94c415a716bbd6f05928f03f2a4 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Thu, 14 Nov 2024 15:49:04 +0100
Subject: [PATCH] Remove const, improve test a bit

---
 cpp/src/arrow/status.cc         | 2 +-
 cpp/src/arrow/status.h          | 2 +-
 cpp/src/arrow/status_internal.h | 2 +-
 cpp/src/arrow/status_test.cc    | 9 +++++++++
 4 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/cpp/src/arrow/status.cc b/cpp/src/arrow/status.cc
index 81f5f88e0f0d1..8cbc6842c4bc3 100644
--- a/cpp/src/arrow/status.cc
+++ b/cpp/src/arrow/status.cc
@@ -167,7 +167,7 @@ void Status::AddContextLine(const char* filename, int line, const char* expr) {
     // We can't add context lines to a StatusConstant's state, so copy it now
     state_ = new State{code(), /*is_constant=*/false, message(), detail()};
   }
-  const_cast<State*>(state_)->msg += ss.str();
+  state_->msg += ss.str();
 }
 #endif
 
diff --git a/cpp/src/arrow/status.h b/cpp/src/arrow/status.h
index a52a3600e434d..853fc284ee317 100644
--- a/cpp/src/arrow/status.h
+++ b/cpp/src/arrow/status.h
@@ -375,7 +375,7 @@ class ARROW_EXPORT [[nodiscard]] Status : public util::EqualityComparable<Status
   };
   // OK status has a `NULL` state_.  Otherwise, `state_` points to
   // a `State` structure containing the error code and message(s)
-  const State* state_;
+  State* state_;
 
   void DeleteState() noexcept {
     // ARROW-2400: On certain compilers, splitting off the slow path improves
diff --git a/cpp/src/arrow/status_internal.h b/cpp/src/arrow/status_internal.h
index 80e6cd2cd610f..f070bc208dbb9 100644
--- a/cpp/src/arrow/status_internal.h
+++ b/cpp/src/arrow/status_internal.h
@@ -31,7 +31,7 @@ class StatusConstant {
         << "StatusConstant is not intended for use with OK status codes";
   }
 
-  operator Status() const {  // NOLINT(runtime/explicit)
+  operator Status() {  // NOLINT(runtime/explicit)
     Status st;
     st.state_ = &state_;
     return st;
diff --git a/cpp/src/arrow/status_test.cc b/cpp/src/arrow/status_test.cc
index 990aadabec8d1..005bdf665f5c8 100644
--- a/cpp/src/arrow/status_test.cc
+++ b/cpp/src/arrow/status_test.cc
@@ -87,6 +87,15 @@ TEST(StatusTest, StatusConstant) {
 
   Status copy = st;
   ASSERT_EQ(&st.message(), &copy.message());
+  Status moved = std::move(st);
+  ASSERT_EQ(&copy.message(), &moved.message());
+  ASSERT_OK(st);
+
+  Status other = constant;
+  ASSERT_EQ(other.code(), StatusCode::Invalid);
+  ASSERT_EQ(other.message(), "default error");
+  ASSERT_EQ(other.detail(), nullptr);
+  ASSERT_EQ(&other.message(), &moved.message());
 }
 
 TEST(StatusTest, AndStatus) {