fix: allow for intlike strings in json parsing

Author: ianhi

src/zarr/core/dtype/npy/common.py

@@ -58,6 +58,9 @@
 IntishFloat = NewType("IntishFloat", float)
 """A type for floats that represent integers, like 1.0 (but not 1.1)."""
 
+IntishStr = NewType("IntishStr", str)
+"""A type for strings that represent integers, like "0" or "42"."""
+
 NumpyEndiannessStr = Literal[">", "<", "="]
 NUMPY_ENDIANNESS_STR: Final = ">", "<", "="
 
@@ -488,6 +491,31 @@ def check_json_intish_float(data: JSON) -> TypeGuard[IntishFloat]:
     return isinstance(data, float) and data.is_integer()
 
 
+def check_json_intish_str(data: JSON) -> TypeGuard[IntishStr]:
+    """
+    Check if a JSON value is a string that represents an integer, like "0", "42", or "-5".
+
+    Parameters
+    ----------
+    data : JSON
+        The JSON value to check.
+
+    Returns
+    -------
+    bool
+        True if the data is a string representing an integer, False otherwise.
+    """
+    if not isinstance(data, str):
+        return False
+
+    try:
+        int(data)
+    except ValueError:
+        return False
+    else:
+        return True
+
+
 def check_json_str(data: JSON) -> TypeGuard[str]:
     """
     Check if a JSON value is a string.

src/zarr/core/dtype/npy/int.py

@@ -26,6 +26,7 @@
 from zarr.core.dtype.npy.common import (
     check_json_int,
     check_json_intish_float,
+    check_json_intish_str,
     endianness_to_numpy_str,
     get_endianness_from_numpy_dtype,
 )
@@ -209,6 +210,10 @@ def from_json_scalar(self, data: JSON, *, zarr_format: ZarrFormat) -> TIntScalar
             return self._cast_scalar_unchecked(data)
         if check_json_intish_float(data):
             return self._cast_scalar_unchecked(int(data))
+
+        if check_json_intish_str(data):
+            return self._cast_scalar_unchecked(int(data))
+
         raise TypeError(f"Invalid type: {data}. Expected an integer.")
 
     def to_json_scalar(self, data: object, *, zarr_format: ZarrFormat) -> int: