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Fix #8442: pass meta_data to EnsureChannelFirst when track_meta is False #8835

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Fix #8442: pass meta_data to EnsureChannelFirst when track_meta is False #8835

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052d055
Fix #8442: pass meta_data to EnsureChannelFirst when track_meta is False
williams145 Apr 18, 2026
36ded05
Fix #8442: simplify channel-first call and add regression test
williams145 May 1, 2026
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2 changes: 1 addition & 1 deletion monai/transforms/io/array.py
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Original file line number Diff line number Diff line change
Expand Up @@ -300,7 +300,7 @@ def __call__(self, filename: Sequence[PathLike] | PathLike, reader: ImageReader
img_array, meta_data, self.simple_keys, pattern=self.pattern, sep=self.sep
)
if self.ensure_channel_first:
img = EnsureChannelFirst()(img)
img = EnsureChannelFirst()(img, meta_dict=meta_data)
if self.image_only:
return img
return img, img.meta if isinstance(img, MetaTensor) else meta_data
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10 changes: 10 additions & 0 deletions tests/transforms/test_load_image.py
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Original file line number Diff line number Diff line change
Expand Up @@ -497,6 +497,16 @@ def test_correct(self, input_param, expected_shape, track_meta):
self.assertNotIsInstance(r, MetaTensor)
self.assertFalse(hasattr(r, "affine"))

def test_track_meta_false_ensure_channel_first(self):
try:
set_track_meta(False)
r = LoadImage(image_only=True, ensure_channel_first=True)(self.test_data)
self.assertTupleEqual(r.shape, (1, 128, 128, 128))
self.assertIsInstance(r, torch.Tensor)
self.assertNotIsInstance(r, MetaTensor)
finally:
set_track_meta(True)
Comment on lines +500 to +508
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@coderabbitai coderabbitai Bot May 1, 2026

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⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Restore the previous track_meta state.

set_track_meta(True) hard-codes the cleanup state and can clobber whatever the suite had before this test ran.

♻️ Proposed fix 
-from monai.data.meta_obj import set_track_meta
+from monai.data.meta_obj import get_track_meta, set_track_meta
@@
     def test_track_meta_false_ensure_channel_first(self):
+        prev_track_meta = get_track_meta()
         try:
             set_track_meta(False)
             r = LoadImage(image_only=True, ensure_channel_first=True)(self.test_data)
             self.assertTupleEqual(r.shape, (1, 128, 128, 128))
             self.assertIsInstance(r, torch.Tensor)
             self.assertNotIsInstance(r, MetaTensor)
         finally:
-            set_track_meta(True)
+            set_track_meta(prev_track_meta)
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
def test_track_meta_false_ensure_channel_first(self):
try:
set_track_meta(False)
r = LoadImage(image_only=True, ensure_channel_first=True)(self.test_data)
self.assertTupleEqual(r.shape, (1, 128, 128, 128))
self.assertIsInstance(r, torch.Tensor)
self.assertNotIsInstance(r, MetaTensor)
finally:
set_track_meta(True)
def test_track_meta_false_ensure_channel_first(self):
prev_track_meta = get_track_meta()
try:
set_track_meta(False)
r = LoadImage(image_only=True, ensure_channel_first=True)(self.test_data)
self.assertTupleEqual(r.shape, (1, 128, 128, 128))
self.assertIsInstance(r, torch.Tensor)
self.assertNotIsInstance(r, MetaTensor)
finally:
set_track_meta(prev_track_meta)
🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@tests/transforms/test_load_image.py` around lines 500 - 508, The test
hard-codes set_track_meta(True) in the finally block which can clobber the
suite's prior state; change the test
(test_track_meta_false_ensure_channel_first) to capture the current state at the
start (e.g., prev = get_track_meta()), call set_track_meta(False) for the test,
and then in the finally block restore the original with set_track_meta(prev)
instead of set_track_meta(True); keep using LoadImage(...) and the same
assertions and ensure get_track_meta/set_track_meta symbols are used to locate
the change.



if __name__ == "__main__":
unittest.main()
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