From aedd0bbe26e1c5b7204b7c5592a1c076345e905e Mon Sep 17 00:00:00 2001
From: vandhanaanatarajan-oss <vandhanaanatarajan@gmail.com>
Date: Sat, 1 Aug 2026 15:17:32 +0100
Subject: [PATCH 1/3] Raise OptionalImportError when user-specified reader is
 not installed (fixes #7437)

Signed-off-by: vandhanaanatarajan-oss <vandhanaanatarajan@gmail.com>
---
 monai/transforms/io/array.py        |  6 +++---
 tests/transforms/test_load_image.py | 11 ++++++++---
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/monai/transforms/io/array.py b/monai/transforms/io/array.py
index aadd96763d..406a148ed9 100644
--- a/monai/transforms/io/array.py
+++ b/monai/transforms/io/array.py
@@ -209,10 +209,10 @@ def __init__(
                     the_reader = look_up_option(_r.lower(), SUPPORTED_READERS)
                 try:
                     self.register(the_reader(*args, **kwargs))
-                except OptionalImportError:
-                    warnings.warn(
+                except OptionalImportError as e:
+                    raise OptionalImportError(
                         f"required package for reader {_r} is not installed, or the version doesn't match requirement."
-                    )
+                    ) from e
                 except TypeError:  # the reader doesn't have the corresponding args/kwargs
                     warnings.warn(f"{_r} is not supported with the given parameters {args} {kwargs}.")
                     self.register(the_reader())
diff --git a/tests/transforms/test_load_image.py b/tests/transforms/test_load_image.py
index 4a470a624c..f45bb5b49b 100644
--- a/tests/transforms/test_load_image.py
+++ b/tests/transforms/test_load_image.py
@@ -221,9 +221,14 @@ def test_nibabel_reader(self, input_param, filenames, expected_shape):
             assert_allclose(result.affine, torch.eye(4))
             self.assertTupleEqual(result.shape, expected_shape)
 
-    @SkipIfNoModule("nibabel")
-    @SkipIfNoModule("cupy")
-    @SkipIfNoModule("kvikio")
+
+    def test_reader_not_installed_raises(self):
+        from unittest.mock import patch
+        from monai.utils import OptionalImportError
+
+        with patch("monai.data.ITKReader", side_effect=OptionalImportError("itk not installed")):
+            with self.assertRaises(OptionalImportError):
+                LoadImage(reader="ITKReader")
     @parameterized.expand([TEST_CASE_GPU_1, TEST_CASE_GPU_2, TEST_CASE_GPU_3, TEST_CASE_GPU_4])
     def test_nibabel_reader_gpu(self, input_param, filenames, expected_shape):
         if torch.__version__.endswith("nv24.8"):

From a476a632caa70e14a16dfdd2758a8c7bb758c48c Mon Sep 17 00:00:00 2001
From: vandhanaanatarajan-oss <vandhanaanatarajan@gmail.com>
Date: Sat, 1 Aug 2026 15:41:36 +0100
Subject: [PATCH 2/3] Address CodeRabbit feedback: add Raises docstring and
 check exception chain in test

Signed-off-by: vandhanaanatarajan-oss <vandhanaanatarajan@gmail.com>
---
 monai/transforms/io/array.py        | 4 ++++
 tests/transforms/test_load_image.py | 6 ++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/monai/transforms/io/array.py b/monai/transforms/io/array.py
index 406a148ed9..28c0524ff3 100644
--- a/monai/transforms/io/array.py
+++ b/monai/transforms/io/array.py
@@ -163,6 +163,10 @@ def __init__(
             expanduser: if True cast filename to Path and call .expanduser on it, otherwise keep filename as is.
             args: additional parameters for reader if providing a reader name.
             kwargs: additional parameters for reader if providing a reader name.
+         Raises:
+            OptionalImportError: If an explicitly selected reader dependency is unavailable.
+
+        
 
         Note:
 
diff --git a/tests/transforms/test_load_image.py b/tests/transforms/test_load_image.py
index f45bb5b49b..68b03ec7bf 100644
--- a/tests/transforms/test_load_image.py
+++ b/tests/transforms/test_load_image.py
@@ -226,9 +226,11 @@ def test_reader_not_installed_raises(self):
         from unittest.mock import patch
         from monai.utils import OptionalImportError
 
-        with patch("monai.data.ITKReader", side_effect=OptionalImportError("itk not installed")):
-            with self.assertRaises(OptionalImportError):
+        original_error = OptionalImportError("itk not installed")
+        with patch("monai.data.ITKReader", side_effect=original_error):
+            with self.assertRaises(OptionalImportError) as context:
                 LoadImage(reader="ITKReader")
+        self.assertIs(context.exception.__cause__, original_error)
     @parameterized.expand([TEST_CASE_GPU_1, TEST_CASE_GPU_2, TEST_CASE_GPU_3, TEST_CASE_GPU_4])
     def test_nibabel_reader_gpu(self, input_param, filenames, expected_shape):
         if torch.__version__.endswith("nv24.8"):

From f3bd473182d592f4f1f02f15f1b8e21da2d4ee7a Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 1 Aug 2026 14:41:53 +0000
Subject: [PATCH 3/3] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 monai/transforms/io/array.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/monai/transforms/io/array.py b/monai/transforms/io/array.py
index 28c0524ff3..49f9642375 100644
--- a/monai/transforms/io/array.py
+++ b/monai/transforms/io/array.py
@@ -166,7 +166,7 @@ def __init__(
          Raises:
             OptionalImportError: If an explicitly selected reader dependency is unavailable.
 
-        
+
 
         Note: