[FIX] Force maskers to be array images instead of proxy images (#588)

* Coerce proxy images to array images.

* Check that maskers are not proxies.

nimare/tests/test_dataset.py

@@ -16,6 +16,9 @@ def test_dataset_smoke():
     dset = dataset.Dataset(db_file)
     dset.update_path(get_test_data_path())
     assert isinstance(dset, nimare.dataset.Dataset)
+    # Test that Dataset.masker is portable
+    assert not nib.is_proxy(dset.masker.mask_img_.dataobj)
+
     methods = [dset.get_images, dset.get_labels, dset.get_metadata, dset.get_texts]
     for method in methods:
         assert isinstance(method(), list)

nimare/tests/test_utils.py

@@ -57,6 +57,7 @@ def test_get_template():
     """Test nimare.utils.get_template."""
     img = utils.get_template(space="mni152_1mm", mask=None)
     assert isinstance(img, nib.Nifti1Image)
+    assert not nib.is_proxy(img.dataobj)
     img = utils.get_template(space="mni152_1mm", mask="brain")
     assert isinstance(img, nib.Nifti1Image)
     img = utils.get_template(space="mni152_1mm", mask="gm")
@@ -67,6 +68,7 @@ def test_get_template():
     assert isinstance(img, nib.Nifti1Image)
     img = utils.get_template(space="mni152_2mm", mask="gm")
     assert isinstance(img, nib.Nifti1Image)
+    assert not nib.is_proxy(img.dataobj)
 
 
 def test_get_resource_path():

nimare/utils.py

@@ -290,6 +290,9 @@ def get_template(space="mni152_2mm", mask=None):
             img = nib.load(op.join(get_resource_path(), "templates/MNI152_2x2x2_brainmask.nii"))
     else:
         raise ValueError(f"Space {space} not supported")
+
+    # Coerce to array-image
+    img = nib.Nifti1Image(img.get_fdata(), affine=img.affine, header=img.header)
     return img
 
 
@@ -309,6 +312,9 @@ def get_masker(mask):
         mask = nib.load(mask)
 
     if isinstance(mask, nib.nifti1.Nifti1Image):
+        # Coerce to array-image
+        mask = nib.Nifti1Image(mask.get_fdata(), affine=mask.affine, header=mask.header)
+
         mask = NiftiMasker(mask)
 
     if not (hasattr(mask, "transform") and hasattr(mask, "inverse_transform")):