make robust to polars missing, change magics name

Author: TrevorBergeron

bigframes/__init__.py

@@ -23,7 +23,7 @@
 from bigframes.session import connect, Session
 from bigframes.version import __version__
 
-_MAGIC_NAMES = ["bigframes"]
+_MAGIC_NAMES = ["bigquery_sql"]
 
 
 def load_ipython_extension(ipython):

bigframes/_magics.py

@@ -40,12 +40,17 @@ def _cell_magic(line, cell):
     args = magic_arguments.parse_argstring(_cell_magic, line)
     if not cell:
         print("Query is missing.")
+        return
     pyformat_args = ipython.user_ns
     dataframe = bigframes.pandas._read_gbq_colab(
         cell, pyformat_args=pyformat_args, dry_run=args.dry_run
     )
     if args.destination_var:
         ipython.push({args.destination_var: dataframe})
     else:
-        display(dataframe)
-    return dataframe
+        with bigframes.option_context(
+            "display.repr_mode",
+            "anywidget",
+        ):
+            display(dataframe)
+    return

bigframes/pandas/io/api.py

@@ -49,6 +49,7 @@
 import pyarrow as pa
 
 import bigframes._config as config
+import bigframes._importing
 import bigframes.core.global_session as global_session
 import bigframes.core.indexes
 import bigframes.dataframe
@@ -356,8 +357,12 @@ def _read_gbq_colab(
             with warnings.catch_warnings():
                 # Don't warning about Polars in SQL cell.
                 # Related to b/437090788.
-                warnings.simplefilter("ignore", bigframes.exceptions.PreviewWarning)
-                config.options.bigquery.enable_polars_execution = True
+                try:
+                    bigframes._importing.import_polars()
+                    warnings.simplefilter("ignore", bigframes.exceptions.PreviewWarning)
+                    config.options.bigquery.enable_polars_execution = True
+                except TypeError:
+                    pass  # don't fail if polars isn't available
 
     return global_session.with_default_session(
         bigframes.session.Session._read_gbq_colab,

tests/system/small/test_magics.py

@@ -20,7 +20,7 @@
 import bigframes
 import bigframes.pandas as bpd
 
-MAGIC_NAME = "bigframes"
+MAGIC_NAME = "bigquery_sql"
 
 
 @pytest.fixture(scope="module")