Merge pull request #516 from martindurant/scalar_binop

fix: Respect inverse in scalar binop

.pre-commit-config.yaml

@@ -62,6 +62,7 @@ repos:
   rev: v1.10.0
   hooks:
   - id: mypy
+    files: "src/"
     args: [--ignore-missing-imports]
     additional_dependencies:
     - dask

pyproject.toml

@@ -111,7 +111,8 @@ src_paths = ["src", "tests"]
 
 [tool.mypy]
 python_version = "3.9"
-files = ["src", "tests"]
+files = ["src"]
+exclude = ["tests/"]
 strict = false
 warn_unused_configs = true
 show_error_codes = true

src/dask_awkward/lib/core.py

@@ -502,9 +502,17 @@ def f(self, other):
             if is_dask_collection(other):
                 task = (op, self.key, *other.__dask_keys__())
                 deps.append(other)
-                plns.append(other.name)
+                if inv:
+                    plns.insert(0, other.name)
+                else:
+                    plns.append(other.name)
             else:
-                task = (op, self.key, other)
+                if inv:
+                    task = (op, other, self.key)
+                else:
+                    task = (op, self.key, other)
+            if inv:
+                plns.reverse()
             graph = HighLevelGraph.from_collections(
                 name,
                 layer=AwkwardMaterializedLayer(
@@ -514,10 +522,16 @@ def f(self, other):
                 ),
                 dependencies=tuple(deps),
             )
-            if isinstance(other, Scalar):
-                meta = op(self._meta, other._meta)
+            if isinstance(other, (Scalar, Array)):
+                if inv:
+                    meta = op(other._meta, self._meta)
+                else:
+                    meta = op(self._meta, other._meta)
             else:
-                meta = op(self._meta, other)
+                if inv:
+                    meta = op(other, self._meta)
+                else:
+                    meta = op(self._meta, other)
             return new_scalar_object(graph, name, meta=meta)
 
         return f

tests/test_core.py

@@ -115,7 +115,7 @@ def test_len(ndjson_points_file: str) -> None:
         assert len(daa) == 10
     daa.eager_compute_divisions()
     assert daa.known_divisions
-    assert len(daa) == 10  # type: ignore
+    assert len(daa) == 10
 
 
 def test_meta_exists(daa: Array) -> None:
@@ -157,7 +157,7 @@ def test_partitions_divisions(ndjson_points_file: str) -> None:
     assert not t1.known_divisions
     t2 = daa.partitions[1]
     assert t2.known_divisions
-    assert t2.divisions == (0, divs[2] - divs[1])  # type: ignore
+    assert t2.divisions == (0, divs[2] - divs[1])
 
 
 def test_array_rebuild(ndjson_points_file: str) -> None:
@@ -537,7 +537,7 @@ def test_compatible_partitions_after_slice() -> None:
     assert_eq(lazy, ccrt)
 
     # sanity
-    assert dak.compatible_partitions(lazy, lazy + 2)  # type: ignore
+    assert dak.compatible_partitions(lazy, lazy + 2)
     assert dak.compatible_partitions(lazy, dak.num(lazy, axis=1) > 2)
 
     assert not dak.compatible_partitions(lazy[:-2], lazy)
@@ -646,6 +646,14 @@ def test_scalar_divisions(daa: Array) -> None:
     assert s.divisions == (None, None)
 
 
+def test_scalar_binop_inv() -> None:
+    # GH #515
+    x = dak.from_lists([[1]])
+    y = x[0]  # scalar
+    assert (0 - y) == -1
+    assert (y - 0) == 1
+
+
 def test_array_persist(daa: Array) -> None:
     daa2 = daa["points"]["x"].persist()
     assert_eq(daa["points"]["x"], daa2)
@@ -886,7 +894,7 @@ def test_shape_only_ops(fn: Callable, tmp_path_factory: pytest.TempPathFactory)
     p = tmp_path_factory.mktemp("zeros-like-flat")
     ak.to_parquet(a, str(p / "file.parquet"))
     lazy = dak.from_parquet(str(p))
-    result = fn(lazy.b)  # type: ignore
+    result = fn(lazy.b)
     with dask.config.set({"awkward.optimization.enabled": True}):
         result.compute()
 
@@ -898,7 +906,7 @@ def test_assign_behavior() -> None:
     with pytest.raises(
         TypeError, match="'mappingproxy' object does not support item assignment"
     ):
-        dx.behavior["should_fail"] = None  # type: ignore
+        dx.behavior["should_fail"] = None
     assert dx.behavior == behavior
 
 
@@ -909,7 +917,7 @@ def test_assign_attrs() -> None:
     with pytest.raises(
         TypeError, match="'mappingproxy' object does not support item assignment"
     ):
-        dx.attrs["should_fail"] = None  # type: ignore
+        dx.attrs["should_fail"] = None
     assert dx.attrs == attrs