From 8294cc479447880a414d43a19ad90c06e10b18a9 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Sat, 16 Dec 2023 19:32:01 +0000
Subject: [PATCH 1/6] fix: touching of unions

---
 src/awkward/_broadcasting.py       | 171 +++++++++++------------------
 src/awkward/_nplikes/typetracer.py |  65 +++++++----
 2 files changed, 108 insertions(+), 128 deletions(-)

diff --git a/src/awkward/_broadcasting.py b/src/awkward/_broadcasting.py
index 1bbaf9693f..d70da4c64f 100644
--- a/src/awkward/_broadcasting.py
+++ b/src/awkward/_broadcasting.py
@@ -773,121 +773,74 @@ def broadcast_any_union():
             else:
                 nextparameters.append(NO_PARAMETERS)
 
-        if not backend.nplike.known_data:
-            # assert False
-            union_num_contents = []
-            length = None
-            for x in contents:
-                if x.is_union:
-                    x._touch_data(recursive=False)
-                    union_num_contents.append(len(x.contents))
-                    if length is None:
-                        length = x.length
-
-            all_combos = list(
-                itertools.product(*[range(x) for x in union_num_contents])
-            )
-
-            tags = backend.index_nplike.empty(length, dtype=np.int8)
-            index = backend.index_nplike.empty(length, dtype=np.int64)
-            numoutputs = None
-            outcontents = []
-            for combo in all_combos:
-                nextinputs = []
-                i = 0
-                for x in inputs:
-                    if isinstance(x, UnionArray):
-                        nextinputs.append(x._contents[combo[i]])
-                        i += 1
-                    else:
-                        nextinputs.append(x)
-                assert len(nextinputs) == len(nextparameters)
-                outcontents.append(
-                    apply_step(
-                        backend,
-                        nextinputs,
-                        action,
-                        depth,
-                        copy.copy(depth_context),
-                        lateral_context,
-                        options,
+        union_tags, union_num_contents, length = [], [], unknown_length
+        for x in contents:
+            if x.is_union:
+                tags = x.tags.raw(backend.index_nplike)
+                union_tags.append(tags)
+                union_num_contents.append(len(x.contents))
+
+                if length is unknown_length:
+                    length = tags.shape[0]
+                elif tags.shape[0] is unknown_length:
+                    continue
+                elif length != tags.shape[0]:
+                    raise ValueError(
+                        "cannot broadcast UnionArray of length {} "
+                        "with UnionArray of length {}{}".format(
+                            length,
+                            tags.shape[0],
+                            in_function(options),
+                        )
                     )
-                )
-                assert isinstance(outcontents[-1], tuple)
-                if numoutputs is not None:
-                    assert numoutputs == len(outcontents[-1])
-                numoutputs = len(outcontents[-1])
 
-            assert numoutputs is not None
+        tags = backend.index_nplike.empty(length, dtype=np.int8)
+        index = backend.index_nplike.empty(length, dtype=np.int64)
 
-        else:
-            union_tags, union_num_contents, length = [], [], None
-            for x in contents:
-                if x.is_union:
-                    tags = x.tags.raw(backend.index_nplike)
-                    union_tags.append(tags)
-                    union_num_contents.append(len(x.contents))
-                    if tags.shape[0] is unknown_length:
-                        continue
-
-                    if length is None:
-                        length = tags.shape[0]
-                    elif length != tags.shape[0]:
-                        raise ValueError(
-                            "cannot broadcast UnionArray of length {} "
-                            "with UnionArray of length {}{}".format(
-                                length,
-                                tags.shape[0],
-                                in_function(options),
-                            )
-                        )
-            assert length is not unknown_length
-
-            # Stack all union tags
-            combos = backend.index_nplike.stack(union_tags, axis=-1)
-            # Build array of indices (c1, c2, c3, ..., cn) of contents in
-            # (union 1, union 2, union 3, ..., union n)
-            all_combos = backend.index_nplike.asarray(
-                list(itertools.product(*[range(x) for x in union_num_contents]))
-            )
+        # Stack all union tags
+        combos = backend.index_nplike.stack(union_tags, axis=-1)
 
-            tags = backend.index_nplike.empty(length, dtype=np.int8)
-            index = backend.index_nplike.empty(length, dtype=np.int64)
-            numoutputs, outcontents = None, []
-            for tag, combo in enumerate(all_combos):
-                mask = backend.index_nplike.all(combos == combo, axis=-1)
-                tags[mask] = tag
-                index[mask] = backend.index_nplike.arange(
-                    backend.index_nplike.count_nonzero(mask), dtype=np.int64
-                )
-                nextinputs = []
-                i = 0
-                for x in inputs:
-                    if isinstance(x, UnionArray):
-                        nextinputs.append(x[mask].project(combo[i]))
-                        i += 1
-                    elif isinstance(x, Content):
-                        nextinputs.append(x[mask])
-                    else:
-                        nextinputs.append(x)
-                outcontents.append(
-                    apply_step(
-                        backend,
-                        nextinputs,
-                        action,
-                        depth,
-                        copy.copy(depth_context),
-                        lateral_context,
-                        options,
-                    )
-                )
-                assert isinstance(outcontents[-1], tuple)
-                if numoutputs is None:
-                    numoutputs = len(outcontents[-1])
+        # Build array of indices (c1, c2, c3, ..., cn) of contents in
+        # (union 1, union 2, union 3, ..., union n)
+        all_combos = list(itertools.product(*[range(x) for x in union_num_contents]))
+
+        numoutputs = None
+        outcontents = []
+
+        for tag, j_contents in enumerate(all_combos):
+            combo = backend.index_nplike.asarray(j_contents, dtype=np.int64)
+            mask = backend.index_nplike.all(combos == combo, axis=-1)
+            tags[mask] = tag
+            index[mask] = backend.index_nplike.arange(
+                backend.index_nplike.count_nonzero(mask), dtype=np.int64
+            )
+            nextinputs = []
+            it_j_contents = iter(j_contents)
+            for x in inputs:
+                if isinstance(x, UnionArray):
+                    nextinputs.append(x[mask].project(next(it_j_contents)))
+                elif isinstance(x, Content):
+                    nextinputs.append(x[mask])
                 else:
-                    assert numoutputs == len(outcontents[-1])
+                    nextinputs.append(x)
+            outcontents.append(
+                apply_step(
+                    backend,
+                    nextinputs,
+                    action,
+                    depth,
+                    copy.copy(depth_context),
+                    lateral_context,
+                    options,
+                )
+            )
+            assert isinstance(outcontents[-1], tuple)
+            if numoutputs is None:
+                numoutputs = len(outcontents[-1])
+            else:
+                assert numoutputs == len(outcontents[-1])
 
-            assert numoutputs is not None
+        assert numoutputs is not None
 
         parameters = parameters_factory(nextparameters, numoutputs)
 
diff --git a/src/awkward/_nplikes/typetracer.py b/src/awkward/_nplikes/typetracer.py
index 90f13bd10d..6f32d4a89e 100644
--- a/src/awkward/_nplikes/typetracer.py
+++ b/src/awkward/_nplikes/typetracer.py
@@ -187,7 +187,7 @@ def _new(
 
         if not isinstance(shape, tuple):
             raise TypeError("typetracer shape must be a tuple")
-        if any(is_unknown_scalar(x) for x in shape):
+        if not all(isinstance(x, int) or x is unknown_length for x in shape):
             raise TypeError("typetracer shape must be integers or unknown-length")
         if not isinstance(dtype, np.dtype):
             raise TypeError("typetracer dtype must be an instance of np.dtype")
@@ -945,7 +945,7 @@ def shape_item_as_index(self, x1: ShapeItem) -> IndexType:
         elif isinstance(x1, int):
             return x1
         else:
-            raise TypeError(f"expected None or int type, received {x1}")
+            raise TypeError(f"expected unknown_length or int type, received {x1}")
 
     def index_as_shape_item(self, x1: IndexType) -> ShapeItem:
         if is_unknown_scalar(x1) and np.issubdtype(x1.dtype, np.integer):
@@ -1294,10 +1294,24 @@ def stack(
         *,
         axis: int = 0,
     ) -> TypeTracerArray:
+        # Ensure all arrays have same ndim
+        ndim = arrays[0].ndim
+        assert all(x.ndim == ndim for x in arrays[1:])
+
+        if axis is None:
+            assert all(x.ndim == 1 for x in arrays)
+        elif axis < 0:
+            axis = ndim + axis
+        if not 0 <= axis < ndim:
+            raise ValueError(axis)
+
         for x in arrays:
             assert isinstance(x, TypeTracerArray)
             try_touch_data(x)
-        raise NotImplementedError
+
+        emptyarrays = [numpy.empty_like((0,) * ndim, dtype=a.dtype) for a in arrays]
+        result = numpy.stack(emptyarrays, axis=axis)
+        return TypeTracerArray._new(result.dtype, result.shape)
 
     def packbits(
         self,
@@ -1436,10 +1450,20 @@ def all(
     ) -> TypeTracerArray:
         assert isinstance(x, TypeTracerArray)
         try_touch_data(x)
-        if axis is None:
-            return TypeTracerArray._new(np.dtype(np.bool_), shape=())
+
+        if axis < 0:
+            axis = axis + x.ndim
+
+        assert 0 <= axis < x.ndim
+
+        if keepdims:
+            next_shape = list(x.shape)
+            next_shape[axis] = 1
+            return TypeTracerArray._new(np.dtype(np.bool_), shape=tuple(next_shape))
         else:
-            raise NotImplementedError
+            next_shape = list(x.shape)
+            del next_shape[axis]
+            return TypeTracerArray._new(np.dtype(np.bool_), shape=tuple(next_shape))
 
     def any(
         self,
@@ -1449,12 +1473,7 @@ def any(
         keepdims: bool = False,
         maybe_out: TypeTracerArray | None = None,
     ) -> TypeTracerArray:
-        assert isinstance(x, TypeTracerArray)
-        try_touch_data(x)
-        if axis is None:
-            return TypeTracerArray._new(np.dtype(np.bool_), shape=())
-        else:
-            raise NotImplementedError
+        return self.all(x, axis=axis, keepdims=keepdims, maybe_out=maybe_out)
 
     def count_nonzero(
         self, x: TypeTracerArray, *, axis: int | tuple[int, ...] | None = None
@@ -1476,7 +1495,20 @@ def min(
     ) -> TypeTracerArray:
         assert isinstance(x, TypeTracerArray)
         try_touch_data(x)
-        raise NotImplementedError
+
+        if axis < 0:
+            axis = axis + x.ndim
+
+        assert 0 <= axis < x.ndim
+
+        if keepdims:
+            next_shape = list(x.shape)
+            next_shape[axis] = 1
+            return TypeTracerArray._new(x.dtype, shape=tuple(next_shape))
+        else:
+            next_shape = list(x.shape)
+            del next_shape[axis]
+            return TypeTracerArray._new(x.dtype, shape=tuple(next_shape))
 
     def max(
         self,
@@ -1486,12 +1518,7 @@ def max(
         keepdims: bool = False,
         maybe_out: TypeTracerArray | None = None,
     ) -> TypeTracerArray:
-        assert isinstance(x, TypeTracerArray)
-        try_touch_data(x)
-        if axis is None:
-            return TypeTracerArray._new(x.dtype, shape=())
-        else:
-            raise NotImplementedError
+        return self.min(x, axis=axis, keepdims=keepdims, maybe_out=maybe_out)
 
     def array_str(
         self,

From 122a0d7049ad0b0c03f18e98b122299948c8e5c9 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Tue, 19 Dec 2023 11:56:26 +0000
Subject: [PATCH 2/6] fix: error for unsupported arguments

---
 src/awkward/_nplikes/typetracer.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/awkward/_nplikes/typetracer.py b/src/awkward/_nplikes/typetracer.py
index 6f32d4a89e..b78bc3018a 100644
--- a/src/awkward/_nplikes/typetracer.py
+++ b/src/awkward/_nplikes/typetracer.py
@@ -1451,6 +1451,19 @@ def all(
         assert isinstance(x, TypeTracerArray)
         try_touch_data(x)
 
+        if isinstance(axis, tuple):
+            raise NotImplementedError
+        if maybe_out is not None:
+            raise NotImplementedError
+
+        if axis is None:
+            return self.all(
+                cast(TypeTracerArray, self.reshape(x, (-1,))),
+                axis=axis,
+                keepdims=keepdims,
+                maybe_out=maybe_out,
+            )
+
         if axis < 0:
             axis = axis + x.ndim
 
@@ -1496,6 +1509,19 @@ def min(
         assert isinstance(x, TypeTracerArray)
         try_touch_data(x)
 
+        if isinstance(axis, tuple):
+            raise NotImplementedError
+        if maybe_out is not None:
+            raise NotImplementedError
+
+        if axis is None:
+            return self.min(
+                cast(TypeTracerArray, self.reshape(x, (-1,))),
+                axis=axis,
+                keepdims=keepdims,
+                maybe_out=maybe_out,
+            )
+
         if axis < 0:
             axis = axis + x.ndim
 

From d6ca283f7b68e51182db26d96771d21283005872 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Tue, 19 Dec 2023 11:59:52 +0000
Subject: [PATCH 3/6] refactor: fix type hint

---
 src/awkward/contents/bytemaskedarray.py    | 2 +-
 src/awkward/contents/content.py            | 2 +-
 src/awkward/contents/emptyarray.py         | 2 +-
 src/awkward/contents/indexedarray.py       | 2 +-
 src/awkward/contents/indexedoptionarray.py | 2 +-
 src/awkward/contents/listarray.py          | 2 +-
 src/awkward/contents/listoffsetarray.py    | 2 +-
 src/awkward/contents/numpyarray.py         | 2 +-
 src/awkward/contents/recordarray.py        | 2 +-
 src/awkward/contents/regulararray.py       | 2 +-
 src/awkward/contents/unionarray.py         | 2 +-
 src/awkward/contents/unmaskedarray.py      | 2 +-
 12 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/awkward/contents/bytemaskedarray.py b/src/awkward/contents/bytemaskedarray.py
index 84742101d3..6881292a2b 100644
--- a/src/awkward/contents/bytemaskedarray.py
+++ b/src/awkward/contents/bytemaskedarray.py
@@ -390,7 +390,7 @@ def _getitem_at(self, where: IndexType):
         else:
             return None
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/content.py b/src/awkward/contents/content.py
index 7315a32ff8..657f09a3d0 100644
--- a/src/awkward/contents/content.py
+++ b/src/awkward/contents/content.py
@@ -700,7 +700,7 @@ def _getitem(self, where):
     def _getitem_at(self, where: IndexType):
         raise NotImplementedError
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         raise NotImplementedError
 
     def _getitem_field(
diff --git a/src/awkward/contents/emptyarray.py b/src/awkward/contents/emptyarray.py
index 831d8c3810..264855317a 100644
--- a/src/awkward/contents/emptyarray.py
+++ b/src/awkward/contents/emptyarray.py
@@ -182,7 +182,7 @@ def _getitem_nothing(self):
     def _getitem_at(self, where: IndexType):
         raise ak._errors.index_error(self, where, "array is empty")
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         return self
 
     def _getitem_field(
diff --git a/src/awkward/contents/indexedarray.py b/src/awkward/contents/indexedarray.py
index 7f30634e52..b0d5701837 100644
--- a/src/awkward/contents/indexedarray.py
+++ b/src/awkward/contents/indexedarray.py
@@ -292,7 +292,7 @@ def _getitem_at(self, where: IndexType):
             raise ak._errors.index_error(self, where)
         return self._content._getitem_at(self._index[where])
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/indexedoptionarray.py b/src/awkward/contents/indexedoptionarray.py
index 6373e61161..6772a76c1e 100644
--- a/src/awkward/contents/indexedoptionarray.py
+++ b/src/awkward/contents/indexedoptionarray.py
@@ -316,7 +316,7 @@ def _getitem_at(self, where: IndexType):
         else:
             return self._content._getitem_at(self._index[where])
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/listarray.py b/src/awkward/contents/listarray.py
index da0ef351bf..bd0bf63828 100644
--- a/src/awkward/contents/listarray.py
+++ b/src/awkward/contents/listarray.py
@@ -320,7 +320,7 @@ def _getitem_at(self, where: IndexType):
         start, stop = self._starts[where], self._stops[where]
         return self._content._getitem_range(start, stop)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/listoffsetarray.py b/src/awkward/contents/listoffsetarray.py
index e35b32320e..fb1991c4d8 100644
--- a/src/awkward/contents/listoffsetarray.py
+++ b/src/awkward/contents/listoffsetarray.py
@@ -320,7 +320,7 @@ def _getitem_at(self, where: IndexType):
         start, stop = self._offsets[where], self._offsets[where + 1]
         return self._content._getitem_range(start, stop)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/numpyarray.py b/src/awkward/contents/numpyarray.py
index 0adba74ba4..d136366446 100644
--- a/src/awkward/contents/numpyarray.py
+++ b/src/awkward/contents/numpyarray.py
@@ -321,7 +321,7 @@ def _getitem_at(self, where: IndexType):
         else:
             return out
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         try:
             out = self._data[start:stop]
         except IndexError as err:
diff --git a/src/awkward/contents/recordarray.py b/src/awkward/contents/recordarray.py
index 30697f6f8f..96825938f6 100644
--- a/src/awkward/contents/recordarray.py
+++ b/src/awkward/contents/recordarray.py
@@ -445,7 +445,7 @@ def _getitem_at(self, where: IndexType):
             raise ak._errors.index_error(self, where)
         return Record(self, where)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
 
diff --git a/src/awkward/contents/regulararray.py b/src/awkward/contents/regulararray.py
index c5748d7f37..4fefc1899a 100644
--- a/src/awkward/contents/regulararray.py
+++ b/src/awkward/contents/regulararray.py
@@ -300,7 +300,7 @@ def _getitem_at(self, where: IndexType):
         start, stop = where * size_scalar, (where + 1) * size_scalar
         return self._content._getitem_range(start, stop)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         index_nplike = self._backend.index_nplike
         if not index_nplike.known_data:
             self._touch_shape(recursive=False)
diff --git a/src/awkward/contents/unionarray.py b/src/awkward/contents/unionarray.py
index 431312c21e..fed19ebe42 100644
--- a/src/awkward/contents/unionarray.py
+++ b/src/awkward/contents/unionarray.py
@@ -552,7 +552,7 @@ def _getitem_at(self, where: IndexType):
         tag, index = self._tags[where], self._index[where]
         return self._contents[tag]._getitem_at(index)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self
diff --git a/src/awkward/contents/unmaskedarray.py b/src/awkward/contents/unmaskedarray.py
index 8afdc6af5d..018146e198 100644
--- a/src/awkward/contents/unmaskedarray.py
+++ b/src/awkward/contents/unmaskedarray.py
@@ -238,7 +238,7 @@ def _getitem_at(self, where: IndexType):
 
         return self._content._getitem_at(where)
 
-    def _getitem_range(self, start: SupportsIndex, stop: IndexType) -> Content:
+    def _getitem_range(self, start: IndexType, stop: IndexType) -> Content:
         if not self._backend.nplike.known_data:
             self._touch_shape(recursive=False)
             return self

From 48034278f66996effd3239f4672f4da679a1776d Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Tue, 19 Dec 2023 12:01:27 +0000
Subject: [PATCH 4/6] fix: normalise slice

---
 src/awkward/_slicing.py         | 39 +++++++--------------------------
 src/awkward/contents/content.py |  2 +-
 src/awkward/index.py            |  4 ++++
 3 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/src/awkward/_slicing.py b/src/awkward/_slicing.py
index bb266c3b53..e09407e66d 100644
--- a/src/awkward/_slicing.py
+++ b/src/awkward/_slicing.py
@@ -2,8 +2,6 @@
 
 from __future__ import annotations
 
-import operator
-
 import awkward as ak
 from awkward._backends.backend import Backend
 from awkward._nplikes import to_nplike
@@ -15,7 +13,7 @@
 from awkward._typing import TYPE_CHECKING, Sequence, TypeAlias, TypeVar
 
 if TYPE_CHECKING:
-    from awkward._nplikes.numpy_like import ArrayLike
+    from awkward._nplikes.numpy_like import ArrayLike, NumpyLike
     from awkward.contents.content import Content
 
 np = NumpyMetadata.instance()
@@ -24,48 +22,27 @@
 SliceItem: TypeAlias = "int | slice | str | None | Ellipsis | ArrayLike | Content"
 
 
-def normalize_slice_item(item, *, backend: Backend):
-    if backend.index_nplike.is_own_array(item):
-        if item.ndim != 0:
-            raise ValueError(
-                f"slice items must be 0D arrays or Python integers, not {item!r}"
-            )
-        else:
-            return item
-    else:
-        return operator.index(item)
-
-
-def normalize_slice(slice_: slice, *, backend: Backend) -> slice:
+def normalize_slice(slice_: slice, *, nplike: NumpyLike) -> slice:
     """
     Args:
         slice_: slice object
-        backend: backend of layout
+        nplike: NumpyLike of array
 
     Return a slice of (start, stop, step) for which the slice items have been
     normalized into index types.
     """
-    index_nplike = backend.index_nplike
 
     start = slice_.start
     stop = slice_.stop
     step = slice_.step
 
-    if index_nplike.known_data:
+    if nplike.known_data:
         return slice_
     # Unknown lengths mean that the slice index is unknown
     else:
-        start = (
-            index_nplike.shape_item_as_index(start)
-            if start is unknown_length
-            else start
-        )
-        stop = (
-            index_nplike.shape_item_as_index(stop) if stop is unknown_length else stop
-        )
-        step = (
-            index_nplike.shape_item_as_index(step) if step is unknown_length else step
-        )
+        start = nplike.shape_item_as_index(start) if start is unknown_length else start
+        stop = nplike.shape_item_as_index(stop) if stop is unknown_length else stop
+        step = nplike.shape_item_as_index(step) if step is unknown_length else step
 
         return slice(start, stop, step)
 
@@ -226,7 +203,7 @@ def normalise_item(item, backend: Backend) -> SliceItem:
         return normalize_integer_like(item)
 
     elif isinstance(item, slice):
-        return normalize_slice(item, backend=backend)
+        return normalize_slice(item, nplike=backend.index_nplike)
 
     elif isinstance(item, str):
         return item
diff --git a/src/awkward/contents/content.py b/src/awkward/contents/content.py
index 657f09a3d0..3cefb566e0 100644
--- a/src/awkward/contents/content.py
+++ b/src/awkward/contents/content.py
@@ -525,7 +525,7 @@ def _getitem(self, where):
         elif isinstance(where, slice) and where.step is None:
             # Ensure that start, stop are non-negative!
             start, stop, _, _ = self._backend.index_nplike.derive_slice_for_length(
-                normalize_slice(where, backend=self._backend), self.length
+                normalize_slice(where, nplike=self._backend.index_nplike), self.length
             )
             return self._getitem_range(start, stop)
 
diff --git a/src/awkward/index.py b/src/awkward/index.py
index 984c1cfd24..814a2106ff 100644
--- a/src/awkward/index.py
+++ b/src/awkward/index.py
@@ -13,6 +13,7 @@
 from awkward._nplikes.numpy_like import NumpyLike, NumpyMetadata
 from awkward._nplikes.shape import ShapeItem
 from awkward._nplikes.typetracer import TypeTracer
+from awkward._slicing import normalize_slice
 from awkward._typing import Any, DType, Final, Self, cast
 
 np: Final = NumpyMetadata.instance()
@@ -214,6 +215,9 @@ def form(self) -> str:
         return _dtype_to_form[self._data.dtype]
 
     def __getitem__(self, where):
+        if isinstance(where, slice):
+            where = normalize_slice(where, nplike=self.nplike)
+
         out = self._data[where]
 
         if hasattr(out, "shape") and len(out.shape) != 0:

From e591e2dda91fb3efbf790d682c6082a2f0b2b900 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Tue, 19 Dec 2023 19:44:34 +0000
Subject: [PATCH 5/6] ci: simplify test workflow (#2869)

* ci: simplify test workflow

* ci: try exporting ForthError

* ci: use macos11 for now

* ci: rename General to Test

* ci: fix wheelhouse path

* ci: better parameterisation

* ci: try cross-platform

* ci: use glob action

* ci: fix ROOT workflow

* ci: fix defaults

* ci: fixes

* ci: fixes

* fix: remaining paths
---
 .github/workflows/coverage.yml                |   2 +-
 .github/workflows/test.yml                    | 209 ++++--------------
 awkward-cpp/include/awkward/util.h            |   2 +-
 noxfile.py                                    |   4 +-
 pyproject.toml                                |   3 +-
 ...nts-test.txt => requirements-test-full.txt |   0
 6 files changed, 43 insertions(+), 177 deletions(-)
 rename requirements-test.txt => requirements-test-full.txt (100%)

diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 7abfbccf43..f328a457b0 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -73,7 +73,7 @@ jobs:
         run: python -m pip list
 
       - name: Install test requirements
-        run: python -m pip install -v -r requirements-test.txt
+        run: python -m pip install -v -r requirements-test-full.txt
 
       - name: Test
         run: >-
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0cd35cf551..f8aaab8a0e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -29,27 +29,38 @@ env:
   SOURCE_DATE_EPOCH: "1668811211"
 
 jobs:
-  Windows:
+  run-tests:
+    name: Run Tests
     strategy:
       matrix:
+        runs-on:
+          - windows-latest
+          - ubuntu-latest
+          - macos-11
         python-version:
           - '3.12'
           - '3.11'
           - '3.10'
           - '3.9'
           - '3.8'
-
         python-architecture:
           - x64
-
+        dependencies-kind:
+          - full
         include:
           - python-version: '3.9'
             python-architecture: x86
+            runs-on: windows-latest
+            dependencies-kind: full
+          - python-version: '3.8'
+            python-architecture: x64
+            runs-on: ubuntu-latest
+            dependencies-kind: minimal
 
-    runs-on: windows-2019
+    runs-on: ${{ matrix.runs-on }}
 
     env:
-      PIP_ONLY_BINARY: cmake,numpy,pandas
+      PIP_ONLY_BINARY: numpy,pandas,pyarrow,numexpr,numexpr
       PIP_PRE: "1"
 
     steps:
@@ -72,7 +83,7 @@ jobs:
         uses: actions/cache@v3
         with:
           path: awkward-cpp/dist
-          key: ${{ github.job }}-${{ matrix.python-version }}-${{ matrix.python-architecture }}-${{ hashFiles('awkward-cpp/**') }}
+          key: ${{ github.job }}-${{ matrix.runs-on }}-${{ matrix.python-version }}-${{ matrix.python-architecture }}-${{ hashFiles('awkward-cpp/**') }}
 
       - name: Build awkward-cpp wheel
         if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
@@ -80,169 +91,24 @@ jobs:
           python -m pip install build
           python -m build -w awkward-cpp
 
-      - name: Install awkward, awkward-cpp, and dependencies
-        run: >-
-          python -m pip install --only-binary "numpy,pandas,pyarrow,numexpr,numexpr"
-          -v . @(get-childitem -path awkward-cpp/dist/*.whl)
-          pytest-github-actions-annotate-failures
-          -r requirements-test.txt
-
-      - name: Print versions
-        run: python -m pip list
-
-      - name: Test specification
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-spec
-
-      - name: Test specification with explicitly defined values
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-spec-explicit
-
-      - name: Test CPU kernels
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-cpu-kernels
-
-      - name: Test
-        run: python -m pytest -vv -rs tests
-
-  MacOS:
-    strategy:
-      matrix:
-        python-version:
-          - '3.12'
-          - '3.11'
-          - '3.10'
-          - '3.9'
-          - '3.8'
-
-    runs-on: macos-11
-
-    env:
-      PIP_ONLY_BINARY: cmake,numpy
-      PIP_PRE: "1"
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-
-      - name: 'Python ${{ matrix.python-version }}'
-        uses: actions/setup-python@v5
-        with:
-          python-version: '${{ matrix.python-version }}'
-          allow-prereleases: true
-
-      - name: Debug wheel tags
-        run: python -m pip debug --verbose
-
-      - name: Generate build files
-        run: pipx run nox -s prepare -- --headers --signatures --tests
-
-      - name: Cache awkward-cpp wheel
-        id: cache-awkward-cpp-wheel
-        uses: actions/cache@v3
-        with:
-          path: ./awkward-cpp/dist
-          key: ${{ github.job }}-${{ matrix.python-version }}-${{ hashFiles('awkward-cpp/**') }}
-
-      - name: Build awkward-cpp wheel
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: |
-          python -m pip install build
-          python -m build -w ./awkward-cpp
-
-      - name: Install awkward, awkward-cpp, dask-awkward, and dependencies
-        run: >-
-          python -m pip install --only-binary "numpy,pandas,pyarrow,numexpr"
-          -v . ./awkward-cpp/dist/*.whl
-          pytest-github-actions-annotate-failures
-          dask-awkward
-          -r requirements-test.txt
-
-      - name: Print versions
-        run: python -m pip list
-
-      - name: Test specification
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-spec
-
-      - name: Test specification with explicitly defined values
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-spec-explicit
-
-      - name: Test CPU kernels
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: python -m pytest -vv -rs awkward-cpp/tests-cpu-kernels
-
-      - name: Test
-        run: python -m pytest -vv -rs tests
-
-  Linux:
-    strategy:
-      matrix:
-        python-version:
-          - '3.12'
-          - '3.11'
-          - '3.10'
-          - '3.9'
-          - '3.8'
-        extra-pip-constraints:
-          - "-r requirements-test.txt"
-        include:
-          # Lower bounds
-          - python-version: '3.8'
-            extra-pip-constraints: "-r requirements-test-minimal.txt"
-
-    runs-on: ubuntu-22.04
-
-    env:
-      PIP_ONLY_BINARY: cmake
-
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: true
-
-      - name: 'Python ${{ matrix.python-version }}'
-        uses: actions/setup-python@v5
-        with:
-          python-version: '${{ matrix.python-version }}'
-          allow-prereleases: true
-
-      - name: Oldest supported CMake
-        uses: jwlawson/actions-setup-cmake@v1.14
-        with:
-          cmake-version: '3.15.x'
-
-      - name: Generate build files
-        run: pipx run nox -s prepare -- --headers --signatures --tests
-
-      - name: Cache awkward-cpp wheel
-        id: cache-awkward-cpp-wheel
-        uses: actions/cache@v3
+      - name: Find built wheel
+        uses: tj-actions/glob@v17
+        id: find-wheel
         with:
-          path: ./awkward-cpp/dist
-          key: ${{ github.job }}-${{ matrix.python-version }}-cmake315-${{ hashFiles('awkward-cpp/**') }}
-
-      - name: Build awkward-cpp wheel
-        if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
-        run: |
-          python -m pip install build
-          python -m build -w ./awkward-cpp
+          files: |
+            awkward-cpp/dist/*.whl
 
       - name: Install awkward, awkward-cpp, and dependencies
         run: >-
-          python -m pip install --only-binary "numpy,pandas,pyarrow,numexpr"
-          -v . ./awkward-cpp/dist/*.whl
-          pytest-github-actions-annotate-failures
-          ${{ matrix.extra-pip-constraints }}
+          python -m pip install -v . ${{ steps.find-wheel.outputs.paths }} pytest-github-actions-annotate-failures
+          -r "requirements-test-${{ matrix.dependencies-kind }}.txt"
 
       - name: Print versions
         run: python -m pip list
 
       - name: Check if kernel specification is sorted
         # We don't need to run this all the time
-        if: matrix.python-version == '3.12'
+        if: (matrix.python-version == '3.12') && (matrix.runs-on == 'ubuntu-latest')
         run: pipx run nox -s diagnostics -- --check-spec-sorted
 
       - name: Test specification
@@ -257,20 +123,21 @@ jobs:
         if: steps.cache-awkward-cpp-wheel.outputs.cache-hit != 'true'
         run: python -m pytest -vv -rs awkward-cpp/tests-cpu-kernels
 
-      - name: Test
+      - name: Test non-kernels
         run: >-
           python -m pytest -vv -rs tests --cov=awkward --cov-report=term
           --cov-report=xml
 
       - name: Upload Codecov results
+        if: (matrix.python-version == '3.9') && (matrix.runs-on == 'ubuntu-latest')
         uses: codecov/codecov-action@v3
-        if: matrix.python-version == '3.9'
 
-  Linux-ROOT-dask-awkward:
+
+  Linux-ROOT:
     runs-on: ubuntu-20.04
 
     env:
-      PIP_ONLY_BINARY: cmake
+      PIP_ONLY_BINARY: numpy,pandas,pyarrow,numexpr,numexpr
 
     timeout-minutes: 30
 
@@ -290,6 +157,7 @@ jobs:
           # Cache invalidates daily by default
           cache-environment: true
           environment-name: awkward
+          # Need Python 3.8 for the cached wheels
           create-args: >-
             python=3.8
             numpy
@@ -311,13 +179,12 @@ jobs:
           python3 -m pip install build
           python3 -m build -w ./awkward-cpp
 
-      - name: Install awkward, awkward-cpp, dask-awkward, and dependencies
+      - name: Install awkward, awkward-cpp, and dependencies
         run: >-
           python -m pip install --only-binary "numpy,pandas,pyarrow,numexpr"
           -v . ./awkward-cpp/dist/*.whl
           pytest-github-actions-annotate-failures
-          dask-awkward
-          -r requirements-test.txt
+          -r requirements-test-full.txt
 
       - name: Print versions
         run: python -m pip list
@@ -331,7 +198,7 @@ jobs:
     runs-on: ubuntu-22.04
 
     env:
-      PIP_ONLY_BINARY: cmake
+      PIP_ONLY_BINARY: numpy,pandas,pyarrow,numexpr,numexpr
 
     steps:
       - uses: actions/checkout@v4
@@ -364,14 +231,12 @@ jobs:
         with:
           image: "docker.io/agoose77/cppyy-wheels:cp311"
           path: "/wheels/."
-          destination: "/tmp/cppyy-wheels"
+          destination: "/tmp/wheelhouse"
 
       - name: Install awkward, awkward-cpp, and dependencies
         run: >-
-          python -m pip install --only-binary "numpy,pandas,pyarrow,numexpr"
-          -v . ./awkward-cpp/dist/*.whl
-          pytest-github-actions-annotate-failures
-          /tmp/cppyy-wheels/*
+          python -m pip install -v --only-binary "numpy,pandas,pyarrow,numexpr"
+          ./ ./awkward-cpp/dist/*.whl /tmp/wheelhouse/* pytest-github-actions-annotate-failures
 
       - name: Print versions
         run: python -m pip list
diff --git a/awkward-cpp/include/awkward/util.h b/awkward-cpp/include/awkward/util.h
index b6ff5c7561..ed1e38ff90 100644
--- a/awkward-cpp/include/awkward/util.h
+++ b/awkward-cpp/include/awkward/util.h
@@ -64,7 +64,7 @@ namespace awkward {
       quote(const std::string& x);
 
     /// @brief Exhaustive list of runtime errors possible in the ForthMachine.
-    enum class ForthError {
+    enum class EXPORT_SYMBOL ForthError {
         // execution can continue
         none,
 
diff --git a/noxfile.py b/noxfile.py
index edce96d05f..61eb0566e7 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -37,7 +37,7 @@ def tests(session):
     """
     Run the unit and regular tests.
     """
-    session.install("-r", "requirements-test.txt", "./awkward-cpp", ".")
+    session.install("-r", "requirements-test-full.txt", "./awkward-cpp", ".")
     session.run("pytest", *session.posargs if session.posargs else ["tests"])
 
 
@@ -65,7 +65,7 @@ def coverage(session):
     """
     Run the unit and regular tests.
     """
-    session.install("-r", "requirements-test.txt", "./awkward-cpp", ".")
+    session.install("-r", "requirements-test-full.txt", "./awkward-cpp", ".")
     session.run(
         "pytest", "tests", "--cov=awkward", "--cov-report=xml", *session.posargs
     )
diff --git a/pyproject.toml b/pyproject.toml
index c4d42987e7..4b7b0640a0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -84,7 +84,8 @@ include = [
     "/CITATION.cff",
     "/CONTRIBUTING.md",
     "/README.md",
-    "/requirements-test.txt"
+    "/requirements-test-full.txt",
+    "/requirements-test-minimal.txt"
 ]
 artifacts = [
     "/tests-cuda-kernels"
diff --git a/requirements-test.txt b/requirements-test-full.txt
similarity index 100%
rename from requirements-test.txt
rename to requirements-test-full.txt

From 95d8679f586999253a61ccf5c5ffe4d607989059 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Tue, 19 Dec 2023 20:19:49 +0000
Subject: [PATCH 6/6] ci: disable PRE

---
 .github/workflows/test.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f8aaab8a0e..45d0ad93b9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -61,7 +61,6 @@ jobs:
 
     env:
       PIP_ONLY_BINARY: numpy,pandas,pyarrow,numexpr,numexpr
-      PIP_PRE: "1"
 
     steps:
       - uses: actions/checkout@v4