undo dtypes._dtype_from_string and apply json only

Author: chelsea-lin

bigframes/core/indexes/base.py

@@ -86,8 +86,8 @@ def __new__(
             pd_df = pandas.DataFrame(index=data)
             block = df.DataFrame(pd_df, session=session)._block
         else:
-            if isinstance(dtype, str):
-                dtype = bigframes.dtypes.bigframes_type(dtype)
+            if isinstance(dtype, str) and dtype.lower() == "json":
+                dtype = bigframes.dtypes.JSON_DTYPE
             pd_index = pandas.Index(data=data, dtype=dtype, name=name)
             pd_df = pandas.DataFrame(index=pd_index)
             block = df.DataFrame(pd_df, session=session)._block

bigframes/dataframe.py

@@ -196,10 +196,11 @@ def __init__(
                 block = block.multi_apply_unary_op(ops.AsTypeOp(to_type=bf_dtype))
 
         else:
+            if isinstance(dtype, str) and dtype.lower() == "json":
+                dtype = bigframes.dtypes.JSON_DTYPE
+
             import bigframes.pandas
 
-            if isinstance(dtype, str):
-                dtype = bigframes.dtypes.bigframes_type(dtype)
             pd_dataframe = pandas.DataFrame(
                 data=data,
                 index=index,  # type:ignore

bigframes/dtypes.py

@@ -637,19 +637,17 @@ def _dtype_from_string(dtype_string: str) -> typing.Optional[Dtype]:
         return BIGFRAMES_STRING_TO_BIGFRAMES[
             typing.cast(DtypeString, str(dtype_string))
         ]
-    if isinstance(dtype_string, str) and dtype_string.lower() == "json":
-        return JSON_DTYPE
     raise TypeError(
         textwrap.dedent(
             f"""
-                Unexpected data type string `{dtype_string}`. The following
+                Unexpected data type string {dtype_string}. The following
                         dtypes are supppted: 'boolean','Float64','Int64',
-                        'int64[pyarrow]','string','string[pyarrow]','json',
+                        'int64[pyarrow]','string','string[pyarrow]',
                         'timestamp[us, tz=UTC][pyarrow]','timestamp[us][pyarrow]',
                         'date32[day][pyarrow]','time64[us][pyarrow]'.
-                        The following pandas `ExtensionDtype` are supported:
-                        pd.BooleanDtype(), pd.Float64Dtype(),
-                        pd.Int64Dtype(), pd.StringDtype(storage="pyarrow"),
+                        The following pandas.ExtensionDtype are supported:
+                        pandas.BooleanDtype(), pandas.Float64Dtype(),
+                        pandas.Int64Dtype(), pandas.StringDtype(storage="pyarrow"),
                         pd.ArrowDtype(pa.date32()), pd.ArrowDtype(pa.time64("us")),
                         pd.ArrowDtype(pa.timestamp("us")),
                         pd.ArrowDtype(pa.timestamp("us", tz="UTC")).

bigframes/operations/base.py

@@ -121,8 +121,8 @@ def __init__(
                 bf_dtype = bigframes.dtypes.bigframes_type(dtype)
                 block = block.multi_apply_unary_op(ops.AsTypeOp(to_type=bf_dtype))
         else:
-            if isinstance(dtype, str):
-                dtype = bigframes.dtypes.bigframes_type(dtype)
+            if isinstance(dtype, str) and dtype.lower() == "json":
+                dtype = bigframes.dtypes.JSON_DTYPE
             pd_series = pd.Series(
                 data=data,
                 index=index,  # type:ignore