Also return expected dtype

Author: ariostas

src/uproot/const.py

@@ -138,8 +138,8 @@
     0x0B: "float16",
     0x0C: "float32",
     0x0D: "float64",
-    0x0E: "uint32",  # Index32
-    0x0F: "uint64",  # Index64
+    0x0E: "int32",  # Index32
+    0x0F: "int64",  # Index64
     0x10: "switch",  # Switch: (uint64, uint32)
     0x11: "int16",  # SplitInt16: split + zigzag encoding
     0x12: "uint16",  # SplitUInt16: split encoding
@@ -150,8 +150,8 @@
     0x17: "float16",  # SplitReal16: split encoding
     0x18: "float32",  # SplitReal32: split encoding
     0x19: "float64",  # SplitReal64: split encoding
-    0x1A: "uint32",  # SplitIndex32: split + delta encoding
-    0x1B: "uint64",  # SplitIndex64: split + delta encoding
+    0x1A: "int32",  # SplitIndex32: split + delta encoding
+    0x1B: "int64",  # SplitIndex64: split + delta encoding
     0x1C: "real32trunc",  # Real32Trunc: float32 with truncated mantissa
     0x1D: "real32quant",  # Real32Quant: float32 with quantized integer representation
 }

src/uproot/models/RNTuple.py

@@ -650,7 +650,7 @@ def read_page(
         ]
         self.deserialize_page_decompressed_buffer(destination, field_metadata)
 
-    def _expected_array_length_and_starts(
+    def _expected_array_length_starts_dtype(
         self, col_idx, cluster_start, cluster_stop, missing_element_padding=0
     ):
         """
@@ -660,7 +660,7 @@ def _expected_array_length_and_starts(
             cluster_stop (int): The first cluster to exclude (i.e. one greater than the last cluster to include).
             missing_element_padding (int): Number of padding elements to add at the start of the array.
 
-        Returns the expected length of the array over the given cluster range, including padding, and also the start indices of each cluster.
+        Returns the expected length of the array over the given cluster range (including padding), the start indices of each cluster, and the dtype of the array.
         """
         field_metadata = self.get_field_metadata(col_idx)
         if field_metadata.dtype_byte in uproot.const.rntuple_index_types:
@@ -690,7 +690,7 @@ def _expected_array_length_and_starts(
             starts.append(total_length)
             total_length += cluster_length
 
-        return total_length, starts
+        return total_length, starts, field_metadata.dtype_result
 
     def read_cluster_range(
         self,
@@ -711,7 +711,7 @@ def read_cluster_range(
         Returns a numpy array with the data from the column.
         """
         field_metadata = self.get_field_metadata(col_idx)
-        total_length, starts = self._expected_array_length_and_starts(
+        total_length, starts, _ = self._expected_array_length_starts_dtype(
             col_idx, cluster_start, cluster_stop, missing_element_padding
         )
         res = numpy.empty(total_length, field_metadata.dtype_result)
@@ -964,7 +964,7 @@ def gpu_deserialize_decompressed_content(
             n_padding = self.column_records[key_nr].first_element_index
             n_padding -= cluster_starts[start_cluster_idx]
             n_padding = max(n_padding, 0)
-            total_length, starts = self._expected_array_length_and_starts(
+            total_length, starts, _ = self._expected_array_length_starts_dtype(
                 ncol, start_cluster_idx, stop_cluster_idx, n_padding
             )
             field_metadata = self.get_field_metadata(ncol)