CLN: move raising TypeError for interpolate with object dtype to Block

pandas/core/generic.py

@@ -7749,11 +7749,6 @@ def interpolate(
             raise ValueError("'method' should be a string, not None.")
 
         obj, should_transpose = (self.T, True) if axis == 1 else (self, False)
-        # GH#53631
-        if np.any(obj.dtypes == object):
-            raise TypeError(
-                f"{type(self).__name__} cannot interpolate with object dtype."
-            )
 
         if isinstance(obj.index, MultiIndex) and method != "linear":
             raise ValueError(

pandas/core/internals/blocks.py

@@ -1388,12 +1388,13 @@ def interpolate(
             # If there are no NAs, then interpolate is a no-op
             return [self.copy(deep=False)]
 
-        # TODO(3.0): this case will not be reachable once GH#53638 is enforced
         if self.dtype == _dtype_obj:
             # only deal with floats
             # bc we already checked that can_hold_na, we don't have int dtype here
             # test_interp_basic checks that we make a copy here
-            return [self.copy(deep=False)]
+            raise TypeError(
+                f"{type(self).__name__} cannot interpolate with object dtype."
+            )
 
         copy, refs = self._get_refs_and_copy(inplace)
 

pandas/tests/copy_view/test_interp_fillna.py

@@ -113,7 +113,7 @@ def test_interp_fill_functions_inplace(func, dtype):
 def test_interpolate_cannot_with_object_dtype():
     df = DataFrame({"a": ["a", np.nan, "c"], "b": 1})
 
-    msg = "DataFrame cannot interpolate with object dtype"
+    msg = ".* cannot interpolate with object dtype"
     with pytest.raises(TypeError, match=msg):
         df.interpolate()
 

pandas/tests/frame/methods/test_interpolate.py

@@ -76,7 +76,7 @@ def test_interp_basic(self):
                 "D": list("abcd"),
             }
         )
-        msg = "DataFrame cannot interpolate with object dtype"
+        msg = ".* cannot interpolate with object dtype"
         with pytest.raises(TypeError, match=msg):
             df.interpolate()
 
@@ -102,7 +102,7 @@ def test_interp_basic_with_non_range_index(self, using_infer_string):
             }
         )
 
-        msg = "DataFrame cannot interpolate with object dtype"
+        msg = ".* cannot interpolate with object dtype"
         if not using_infer_string:
             with pytest.raises(TypeError, match=msg):
                 df.set_index("C").interpolate()
@@ -296,14 +296,14 @@ def test_interp_raise_on_only_mixed(self, axis):
                 "E": [1, 2, 3, 4],
             }
         )
-        msg = "DataFrame cannot interpolate with object dtype"
+        msg = ".* cannot interpolate with object dtype"
         with pytest.raises(TypeError, match=msg):
             df.astype("object").interpolate(axis=axis)
 
     def test_interp_raise_on_all_object_dtype(self):
         # GH 22985
         df = DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]}, dtype="object")
-        msg = "DataFrame cannot interpolate with object dtype"
+        msg = ".* cannot interpolate with object dtype"
         with pytest.raises(TypeError, match=msg):
             df.interpolate()
 

pandas/tests/series/methods/test_interpolate.py

@@ -790,11 +790,9 @@ def test_interpolate_unsorted_index(self, ascending, expected_values):
 
     def test_interpolate_asfreq_raises(self):
         ser = Series(["a", None, "b"], dtype=object)
-        msg2 = "Series cannot interpolate with object dtype"
-        msg = "Invalid fill method"
-        with pytest.raises(TypeError, match=msg2):
-            with pytest.raises(ValueError, match=msg):
-                ser.interpolate(method="asfreq")
+        msg = "Can not interpolate with method=asfreq"
+        with pytest.raises(ValueError, match=msg):
+            ser.interpolate(method="asfreq")
 
     def test_interpolate_fill_value(self):
         # GH#54920