DEPR: create_block_manager_from_blocks (#55355)

* DEPR: create_block_manager_from_blocks

* lint fixup

Author: jbrockmendel

pandas/core/internals/__init__.py

@@ -16,7 +16,6 @@
 from pandas.core.internals.managers import (
     BlockManager,
     SingleBlockManager,
-    create_block_manager_from_blocks,
 )
 
 __all__ = [
@@ -31,8 +30,6 @@
     "SingleBlockManager",
     "SingleArrayManager",
     "concatenate_managers",
-    # this is preserved here for downstream compatibility (GH-33892)
-    "create_block_manager_from_blocks",
 ]
 
 
@@ -41,6 +38,18 @@ def __getattr__(name: str):
 
     from pandas.util._exceptions import find_stack_level
 
+    if name == "create_block_manager_from_blocks":
+        # GH#33892
+        warnings.warn(
+            f"{name} is deprecated and will be removed in a future version. "
+            "Use public APIs instead.",
+            DeprecationWarning,
+            stacklevel=find_stack_level(),
+        )
+        from pandas.core.internals.managers import create_block_manager_from_blocks
+
+        return create_block_manager_from_blocks
+
     if name in ["NumericBlock", "ObjectBlock"]:
         warnings.warn(
             f"{name} is deprecated and will be removed in a future version. "

pandas/tests/internals/test_api.py

@@ -4,6 +4,7 @@
 """
 
 import pandas as pd
+import pandas._testing as tm
 from pandas.core import internals
 from pandas.core.internals import api
 
@@ -37,7 +38,6 @@ def test_namespace():
         "SingleBlockManager",
         "SingleArrayManager",
         "concatenate_managers",
-        "create_block_manager_from_blocks",
     ]
 
     result = [x for x in dir(internals) if not x.startswith("__")]
@@ -51,3 +51,15 @@ def test_make_block_2d_with_dti():
 
     assert blk.shape == (1, 3)
     assert blk.values.shape == (1, 3)
+
+
+def test_create_block_manager_from_blocks_deprecated():
+    # GH#33892
+    # If they must, downstream packages should get this from internals.api,
+    #  not internals.
+    msg = (
+        "create_block_manager_from_blocks is deprecated and will be "
+        "removed in a future version. Use public APIs instead"
+    )
+    with tm.assert_produces_warning(DeprecationWarning, match=msg):
+        internals.create_block_manager_from_blocks