From dae089c8b4c2398ef0604a9675be8fe9cb619180 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Fri, 12 Mar 2021 09:36:16 -0800
Subject: [PATCH] REF: consistent arguments for
 create_block_manager_from_blocks

---
 pandas/core/internals/construction.py | 32 +++++++++++++++++++++++----
 pandas/core/internals/managers.py     | 31 +++++++++-----------------
 2 files changed, 38 insertions(+), 25 deletions(-)

diff --git a/pandas/core/internals/construction.py b/pandas/core/internals/construction.py
index 63a437a91f6e4..5ec4f8623aa0f 100644
--- a/pandas/core/internals/construction.py
+++ b/pandas/core/internals/construction.py
@@ -296,6 +296,8 @@ def ndarray_to_mgr(
     )
     values = values.T
 
+    _check_values_indices_shape_match(values, index, columns)
+
     # if we don't have a dtype specified, then try to convert objects
     # on the entire block; this is to convert if we have datetimelike's
     # embedded in an object type
@@ -317,15 +319,37 @@ def ndarray_to_mgr(
         else:
             datelike_vals = maybe_infer_to_datetimelike(values)
             datelike_vals = maybe_squeeze_dt64tz(datelike_vals)
-            block_values = [datelike_vals]
+            nb = new_block(datelike_vals, placement=slice(len(columns)), ndim=2)
+            block_values = [nb]
     else:
-        # error: List item 0 has incompatible type "Union[ExtensionArray, ndarray]";
-        # expected "Block"
-        block_values = [maybe_squeeze_dt64tz(values)]  # type: ignore[list-item]
+        new_values = maybe_squeeze_dt64tz(values)
+        nb = new_block(new_values, placement=slice(len(columns)), ndim=2)
+        block_values = [nb]
+
+    if len(columns) == 0:
+        block_values = []
 
     return create_block_manager_from_blocks(block_values, [columns, index])
 
 
+def _check_values_indices_shape_match(
+    values: np.ndarray, index: Index, columns: Index
+) -> None:
+    """
+    Check that the shape implied by our axes matches the actual shape of the
+    data.
+    """
+    if values.shape[0] != len(columns):
+        # Could let this raise in Block constructor, but we get a more
+        #  helpful exception message this way.
+        if values.shape[1] == 0:
+            raise ValueError("Empty data passed with indices specified.")
+
+        passed = values.T.shape
+        implied = (len(index), len(columns))
+        raise ValueError(f"Shape of passed values is {passed}, indices imply {implied}")
+
+
 def maybe_squeeze_dt64tz(dta: ArrayLike) -> ArrayLike:
     """
     If we have a tzaware DatetimeArray with shape (1, N), squeeze to (N,)
diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index 6bd3e37ae101e..1bbd253fc56c5 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -1726,30 +1726,19 @@ def set_values(self, values: ArrayLike):
 # Constructor Helpers
 
 
-def create_block_manager_from_blocks(blocks, axes: List[Index]) -> BlockManager:
+def create_block_manager_from_blocks(
+    blocks: List[Block], axes: List[Index]
+) -> BlockManager:
     try:
-        if len(blocks) == 1 and not isinstance(blocks[0], Block):
-            # if blocks[0] is of length 0, return empty blocks
-            if not len(blocks[0]):
-                blocks = []
-            else:
-                # It's OK if a single block is passed as values, its placement
-                # is basically "all items", but if there're many, don't bother
-                # converting, it's an error anyway.
-                blocks = [
-                    new_block(
-                        values=blocks[0], placement=slice(0, len(axes[0])), ndim=2
-                    )
-                ]
-
         mgr = BlockManager(blocks, axes)
-        mgr._consolidate_inplace()
-        return mgr
 
-    except ValueError as e:
-        blocks = [getattr(b, "values", b) for b in blocks]
-        tot_items = sum(b.shape[0] for b in blocks)
-        raise construction_error(tot_items, blocks[0].shape[1:], axes, e)
+    except ValueError as err:
+        arrays = [blk.values for blk in blocks]
+        tot_items = sum(arr.shape[0] for arr in arrays)
+        raise construction_error(tot_items, arrays[0].shape[1:], axes, err)
+
+    mgr._consolidate_inplace()
+    return mgr
 
 
 # We define this here so we can override it in tests.extension.test_numpy