Use the intended dtype for data of all-masked arrays.

pp-mo · pp-mo · commit 58aca8827684 · 2025-10-30T15:53:49.000Z
diff --git a/lib/iris/_merge.py b/lib/iris/_merge.py
@@ -1279,7 +1279,7 @@ def merge(self, unique=True):
                 if some_are_dataless:
                     # Some parts were dataless: fill these with a lazy all-missing array.
                     missing_part = da.ma.masked_array(
-                        data=da.zeros(part_shape, dtype=np.dtype("u1")),
+                        data=da.zeros(part_shape, dtype=part_dtype),
                         mask=da.ones(part_shape, dtype=bool),
                         dtype=part_dtype,
                     )

Original file line number	Diff line number	Diff line change
`@@ -1279,7 +1279,7 @@ def merge(self, unique=True):`
`1279`	`1279`	`if some_are_dataless:`
`1280`	`1280`	`# Some parts were dataless: fill these with a lazy all-missing array.`
`1281`	`1281`	`missing_part = da.ma.masked_array(`
`1282`		`- data=da.zeros(part_shape, dtype=np.dtype("u1")),`
	`1282`	`+ data=da.zeros(part_shape, dtype=part_dtype),`
`1283`	`1283`	`mask=da.ones(part_shape, dtype=bool),`
`1284`	`1284`	`dtype=part_dtype,`
`1285`	`1285`	`)`