From 2da78b43d36c64bf09686838c0b1ad2677099c54 Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Mon, 13 Nov 2023 17:59:23 +0000
Subject: [PATCH 1/2] fix: make deep (meta) copy in dak.copy

---
 src/dask_awkward/lib/structure.py | 8 +++++++-
 tests/test_structure.py           | 7 ++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/dask_awkward/lib/structure.py b/src/dask_awkward/lib/structure.py
index fc0bbf09..7144bc35 100644
--- a/src/dask_awkward/lib/structure.py
+++ b/src/dask_awkward/lib/structure.py
@@ -3,6 +3,7 @@
 import builtins
 import warnings
 from collections.abc import Iterable, Mapping, Sequence
+from copy import deepcopy
 from numbers import Number
 from typing import TYPE_CHECKING, Any
 
@@ -315,7 +316,12 @@ def combinations(
 
 @borrow_docstring(ak.copy)
 def copy(array: Array) -> Array:
-    return array
+    return Array(
+        array._dask,
+        array._name,
+        deepcopy(array._meta),
+        array._divisions,
+    )
 
 
 class _FillNoneFn:
diff --git a/tests/test_structure.py b/tests/test_structure.py
index 23a190b4..53d4efcf 100644
--- a/tests/test_structure.py
+++ b/tests/test_structure.py
@@ -388,11 +388,8 @@ def test_sort(daa, caa, ascending):
 
 
 def test_copy(daa):
-    with pytest.raises(
-        DaskAwkwardNotImplemented,
-        match="This function is not necessary in the context of dask-awkward.",
-    ):
-        dak.copy(daa)
+    result = dak.copy(daa)
+    assert result._meta is not daa._meta
 
 
 @pytest.mark.parametrize(

From 08c48c63cdfde97895bfc8af103d0456c8437f9e Mon Sep 17 00:00:00 2001
From: Angus Hollands <goosey15@gmail.com>
Date: Mon, 13 Nov 2023 18:02:37 +0000
Subject: [PATCH 2/2] fix: only copy metadata

---
 src/dask_awkward/lib/structure.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/dask_awkward/lib/structure.py b/src/dask_awkward/lib/structure.py
index 7144bc35..6780b30c 100644
--- a/src/dask_awkward/lib/structure.py
+++ b/src/dask_awkward/lib/structure.py
@@ -316,10 +316,15 @@ def combinations(
 
 @borrow_docstring(ak.copy)
 def copy(array: Array) -> Array:
+    # Make a copy of meta, but don't try and copy the layout;
+    # dask-awkward's copy is metadata-only
+    old_meta = array._meta
+    new_meta = ak.Array(old_meta.layout, behavior=deepcopy(old_meta._behavior))
+
     return Array(
         array._dask,
         array._name,
-        deepcopy(array._meta),
+        new_meta,
         array._divisions,
     )