Fix #454 (#465)

* Fix #454

* Update changelog

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning][].
 ### Fixes
 
 -   Fix that `define_clonotype_clusters` could not retreive `within_group` columns from MuData ([#459](https://github.com/scverse/scirpy/pull/459))
+-   Fix that AIRR Rearrangment fields of integer types could not be written when their value was None ([#465](https://github.com/scverse/scirpy/pull/465))
 
 ## v0.13.1
 

src/scirpy/io/_io.py

@@ -584,9 +584,9 @@ def write_airr(adata: DataHandler.TYPE, filename: Union[str, Path], **kwargs) ->
     for tmp_cell in airr_cells:
         for chain in tmp_cell.to_airr_records():
             # workaround for AIRR library writing out int field as floats (if it happens to be a float)
-            for f in chain:
-                if RearrangementSchema.type(f) == "integer":
-                    chain[f] = int(chain[f])
+            for field, value in chain.items():
+                if RearrangementSchema.type(field) == "integer" and value is not None:
+                    chain[field] = int(value)
             writer.write(chain)
     writer.close()
 

src/scirpy/tests/test_io.py

@@ -236,6 +236,15 @@ def test_airr_roundtrip_conversion(anndata_from_10x_sample, tmp_path):
     pdt.assert_frame_equal(anndata.obs, anndata2.obs, check_dtype=False, check_categorical=False)
 
 
+def test_write_airr_none_field_issue_454(tmp_path):
+    cell = AirrCell("cell1")
+    chain = cell.empty_chain_dict()
+    chain["d_sequence_end"] = None
+    cell.add_chain(chain)
+    adata = from_airr_cells([cell])
+    write_airr(adata, tmp_path / "test.airr.tsv")
+
+
 @pytest.mark.extra
 @pytest.mark.parametrize(
     "anndata_from_10x_sample",