From cde842649d3ed048d687ad8e159c0d97315adca4 Mon Sep 17 00:00:00 2001
From: Vitalii Lazebnyi <18521734+VitaliiLazebnyi@users.noreply.github.com>
Date: Thu, 15 Oct 2026 17:20:49 +0900
Subject: [PATCH] raise Vips::Error if copy_memory fails

vips_image_copy_memory() returns NULL on error, for example when the
source cannot be decoded. copy_memory wrapped that pointer without a
check, so the next call on the returned image segfaulted.

Fixes #442
---
 CHANGELOG.md       |  2 ++
 lib/vips/image.rb  |  2 ++
 spec/image_spec.rb | 13 +++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 54c5b59..dcbe232 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## master
 
+* raise Vips::Error if `copy_memory` fails [VitaliiLazebnyi]
+
 ## Version 2.3.0 (2025-12-10)
 
 * move library_name out of the global namespace and into FFI [jcupitt]
diff --git a/lib/vips/image.rb b/lib/vips/image.rb
index 9e6206e..1a4347b 100644
--- a/lib/vips/image.rb
+++ b/lib/vips/image.rb
@@ -1018,6 +1018,8 @@ def add_alpha
     # @return [Image] new memory image
     def copy_memory
       new_image = Vips.vips_image_copy_memory self
+      raise Vips::Error if new_image.null?
+
       Vips::Image.new new_image
     end
 
diff --git a/spec/image_spec.rb b/spec/image_spec.rb
index 7837d4c..f1eeff7 100644
--- a/spec/image_spec.rb
+++ b/spec/image_spec.rb
@@ -81,6 +81,19 @@
     expect { img.write_to_memory }.to raise_exception(Vips::Error)
   end
 
+  it "can copy an image to memory" do
+    image = (Vips::Image.black(16, 16) + 128).copy_memory
+
+    expect(image.width).to eq(16)
+    expect(image.height).to eq(16)
+    expect(image.avg).to eq(128)
+  end
+
+  it "will raise VipsError if copy_memory fails" do
+    img = Vips::Image.new_from_file simg("coffee.gif")
+    expect { img.copy_memory }.to raise_exception(Vips::Error)
+  end
+
   it "throws an error when trying to load an image from memory with unknown size" do
     data = FFI::Pointer.new(1)
     expect { Vips::Image.new_from_memory(data, 16, 16, 1, :uchar) }.to raise_error(Vips::Error)