[ArrayManager] Add SingleArrayManager to back a Series

.github/workflows/ci.yml

@@ -165,6 +165,9 @@ jobs:
         pytest pandas/tests/resample/
         pytest pandas/tests/reshape/merge
 
+        pytest pandas/tests/series/methods
+        pytest pandas/tests/series/test_*
+
         # indexing subset (temporary since other tests don't pass yet)
         pytest pandas/tests/frame/indexing/test_indexing.py::TestDataFrameIndexing::test_setitem_boolean
         pytest pandas/tests/frame/indexing/test_where.py

pandas/_typing.py

@@ -58,6 +58,8 @@
     from pandas.core.internals import (
         ArrayManager,
         BlockManager,
+        SingleArrayManager,
+        SingleBlockManager,
     )
     from pandas.core.resample import Resampler
     from pandas.core.series import Series
@@ -184,3 +186,4 @@
 
 # internals
 Manager = Union["ArrayManager", "BlockManager"]
+SingleManager = Union["SingleArrayManager", "SingleBlockManager"]

pandas/core/construction.py

@@ -481,7 +481,6 @@ def sanitize_array(
     DataFrame constructor, as the dtype keyword there may be interpreted as only
     applying to a subset of columns, see GH#24435.
     """
-
     if isinstance(data, ma.MaskedArray):
         data = sanitize_masked_array(data)
 
@@ -555,6 +554,7 @@ def sanitize_array(
             inferred = lib.infer_dtype(subarr, skipna=False)
             if inferred in {"interval", "period"}:
                 subarr = array(subarr)
+                subarr = extract_array(subarr, extract_numpy=True)
 
     return subarr
 

pandas/core/generic.py

@@ -138,6 +138,7 @@
 from pandas.core.internals import (
     ArrayManager,
     BlockManager,
+    SingleArrayManager,
 )
 from pandas.core.internals.construction import mgr_to_mgr
 from pandas.core.missing import find_valid_index
@@ -5563,7 +5564,7 @@ def _protect_consolidate(self, f):
         Consolidate _mgr -- if the blocks have changed, then clear the
         cache
         """
-        if isinstance(self._mgr, ArrayManager):
+        if isinstance(self._mgr, (ArrayManager, SingleArrayManager)):
             return f()
         blocks_before = len(self._mgr.blocks)
         result = f()

pandas/core/groupby/generic.py

@@ -108,10 +108,7 @@
     all_indexes_same,
 )
 import pandas.core.indexes.base as ibase
-from pandas.core.internals import (
-    ArrayManager,
-    BlockManager,
-)
+from pandas.core.internals import ArrayManager
 from pandas.core.series import Series
 from pandas.core.util.numba_ import maybe_use_numba
 
@@ -1151,18 +1148,18 @@ def py_fallback(values: ArrayLike) -> ArrayLike:
             #  in the operation.  We un-split here.
             result = result._consolidate()
             assert isinstance(result, (Series, DataFrame))  # for mypy
+            # unwrap DataFrame/Series to get array
             mgr = result._mgr
-            assert isinstance(mgr, BlockManager)
-
-            # unwrap DataFrame to get array
-            if len(mgr.blocks) != 1:
+            arrays = mgr.arrays
+            if len(arrays) != 1:
                 # We've split an object block! Everything we've assumed
                 # about a single block input returning a single block output
                 # is a lie. See eg GH-39329
                 return mgr.as_array()
             else:
-                result = mgr.blocks[0].values
-                return result
+                # We are a single block from a BlockManager
+                # or one array from SingleArrayManager
+                return arrays[0]
 
         def array_func(values: ArrayLike) -> ArrayLike:
 

pandas/core/indexing.py

@@ -1590,7 +1590,11 @@ def _setitem_with_indexer(self, indexer, value, name="iloc"):
 
         # if there is only one block/type, still have to take split path
         # unless the block is one-dimensional or it can hold the value
-        if not take_split_path and self.obj._mgr.blocks and self.ndim > 1:
+        if (
+            not take_split_path
+            and getattr(self.obj._mgr, "blocks", False)
+            and self.ndim > 1
+        ):
             # in case of dict, keys are indices
             val = list(value.values()) if isinstance(value, dict) else value
             blk = self.obj._mgr.blocks[0]

pandas/core/internals/__init__.py

@@ -1,5 +1,11 @@
-from pandas.core.internals.array_manager import ArrayManager
-from pandas.core.internals.base import DataManager
+from pandas.core.internals.array_manager import (
+    ArrayManager,
+    SingleArrayManager,
+)
+from pandas.core.internals.base import (
+    DataManager,
+    SingleDataManager,
+)
 from pandas.core.internals.blocks import (  # io.pytables, io.packers
     Block,
     CategoricalBlock,
@@ -34,7 +40,9 @@
     "DataManager",
     "ArrayManager",
     "BlockManager",
+    "SingleDataManager",
     "SingleBlockManager",
+    "SingleArrayManager",
     "concatenate_managers",
     # those two are preserved here for downstream compatibility (GH-33892)
     "create_block_manager_from_arrays",