From 1c5ad91724755e0cf9f82dac6101fe36f7499b11 Mon Sep 17 00:00:00 2001
From: Aaditya Srinivasan <aadityasri03@gmail.com>
Date: Mon, 22 Jun 2026 16:52:58 +0530
Subject: [PATCH 1/3] GH-45187: [Ruby] Ensure initializing all rb_memory_view_t
 members

---
 ruby/red-arrow/ext/arrow/memory-view.cpp |  9 ++---
 ruby/red-arrow/test/test-memory-view.rb  | 51 ++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/ruby/red-arrow/ext/arrow/memory-view.cpp b/ruby/red-arrow/ext/arrow/memory-view.cpp
index a3135310c97d..982b8f10ae4c 100644
--- a/ruby/red-arrow/ext/arrow/memory-view.cpp
+++ b/ruby/red-arrow/ext/arrow/memory-view.cpp
@@ -32,6 +32,7 @@
 #endif
 
 #include <sstream>
+#include <cstring>
 
 namespace red_arrow {
   namespace memory_view {
@@ -220,6 +221,7 @@ namespace red_arrow {
         return false;
       }
       auto view_ = reinterpret_cast<memory_view *>(view);
+      memset(view_, 0, sizeof(memory_view));
       view_->obj = obj;
       view_->private_data = new PrivateData();
       auto array = GARROW_ARRAY(RVAL2GOBJ(obj));
@@ -231,9 +233,6 @@ namespace red_arrow {
       }
       view_->readonly = true;
       view_->ndim = 1;
-      view_->shape = NULL;
-      view_->strides = NULL;
-      view_->sub_offsets = NULL;
       return true;
     }
 
@@ -258,6 +257,7 @@ namespace red_arrow {
         return false;
       }
       auto view_ = reinterpret_cast<memory_view *>(view);
+      memset(view_, 0, sizeof(memory_view));
       view_->obj = obj;
       auto buffer = GARROW_BUFFER(RVAL2GOBJ(obj));
       auto arrow_buffer = garrow_buffer_get_raw(buffer);
@@ -275,9 +275,6 @@ namespace red_arrow {
       view_->byte_size = arrow_buffer->size();
       view_->readonly = true;
       view_->ndim = 1;
-      view_->shape = NULL;
-      view_->strides = NULL;
-      view_->sub_offsets = NULL;
       return true;
     }
 
diff --git a/ruby/red-arrow/test/test-memory-view.rb b/ruby/red-arrow/test/test-memory-view.rb
index 0b9c98c407f4..676e9268b0e0 100644
--- a/ruby/red-arrow/test/test-memory-view.rb
+++ b/ruby/red-arrow/test/test-memory-view.rb
@@ -431,4 +431,55 @@ def little_endian?
                    ])
     end
   end
+
+  sub_test_case("uninitialized rb_memory_view_t") do
+    def setup
+      libruby = Fiddle.dlopen(nil)
+
+      @rb_memory_view_get = Fiddle::Function.new(
+        libruby["rb_memory_view_get"],
+        [
+          Fiddle::TYPE_UINTPTR_T,
+          Fiddle::TYPE_VOIDP,
+          Fiddle::TYPE_INT,
+        ],
+        Fiddle::TYPE_BOOL
+      )
+
+      @rb_memory_view_release = Fiddle::Function.new(
+        libruby["rb_memory_view_release"],
+        [
+          Fiddle::TYPE_VOIDP,
+        ],
+        Fiddle::TYPE_BOOL
+      )
+    end
+
+    def assert_release(target)
+      size = 256 # We should use sizeof(rb_memory_view_t) but it isn't available from Ruby.
+      Fiddle::Pointer.malloc(size, Fiddle::RUBY_FREE) do |view|
+        size.times do |i|
+          view[i] = 0xAA
+        end
+
+        assert do
+          @rb_memory_view_get.call(Fiddle.dlwrap(target), view, 0)
+        end
+
+        assert do
+          @rb_memory_view_release.call(view)
+        end
+      end
+    end
+
+    test("Int32Array") do
+      array = Arrow::Int32Array.new([1, 2, 3, 4, 5])
+      assert_release(array)
+    end
+
+    test("Buffer") do
+      buffer = Arrow::Buffer.new("hello")
+      assert_release(buffer)
+    end
+  end
 end

From 1a9fbd2cd45dbfe69e274c1d5a6146e48223615e Mon Sep 17 00:00:00 2001
From: Sutou Kouhei <kou@cozmixng.org>
Date: Tue, 23 Jun 2026 15:17:45 +0900
Subject: [PATCH 2/3] One more note

---
 ruby/red-arrow/test/test-memory-view.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ruby/red-arrow/test/test-memory-view.rb b/ruby/red-arrow/test/test-memory-view.rb
index 676e9268b0e0..8aa5728a56a4 100644
--- a/ruby/red-arrow/test/test-memory-view.rb
+++ b/ruby/red-arrow/test/test-memory-view.rb
@@ -456,7 +456,9 @@ def setup
     end
 
     def assert_release(target)
-      size = 256 # We should use sizeof(rb_memory_view_t) but it isn't available from Ruby.
+      # We should use sizeof(rb_memory_view_t) but it isn't available from Ruby.
+      # 256 must be larger than sizeof(rb_memory_view_t).
+      size = 256
       Fiddle::Pointer.malloc(size, Fiddle::RUBY_FREE) do |view|
         size.times do |i|
           view[i] = 0xAA

From c4496b0772db16fbca2957c7232e47f9c48cdcf7 Mon Sep 17 00:00:00 2001
From: Sutou Kouhei <kou@cozmixng.org>
Date: Tue, 23 Jun 2026 15:18:20 +0900
Subject: [PATCH 3/3] Sort

---
 ruby/red-arrow/ext/arrow/memory-view.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ruby/red-arrow/ext/arrow/memory-view.cpp b/ruby/red-arrow/ext/arrow/memory-view.cpp
index 982b8f10ae4c..3869b45583d8 100644
--- a/ruby/red-arrow/ext/arrow/memory-view.cpp
+++ b/ruby/red-arrow/ext/arrow/memory-view.cpp
@@ -31,8 +31,8 @@
 #  undef private
 #endif
 
-#include <sstream>
 #include <cstring>
+#include <sstream>
 
 namespace red_arrow {
   namespace memory_view {