Revert "Make the ros2cli output always line buffered (#659)"

This reverts commit 0075a71.

Signed-off-by: Tomoya Fujita <Tomoya.Fujita@sony.com>

ros2cli/ros2cli/cli.py

@@ -14,10 +14,7 @@
 # limitations under the License.
 
 import argparse
-import builtins
-import functools
 import signal
-import sys
 
 from ros2cli.command import add_subparsers_on_demand
 
@@ -32,14 +29,6 @@ def main(*, script_name='ros2', argv=None, description=None, extension=None):
         description=description,
         formatter_class=argparse.RawDescriptionHelpFormatter
     )
-    parser.add_argument(
-        '--use-python-default-buffering',
-        action='store_true',
-        default=False,
-        help=(
-            'Do not force line buffering in stdout and instead use the python default buffering, '
-            'which might be affected by PYTHONUNBUFFERED/-u and depends on whatever stdout is '
-            'interactive or not'))
 
     # add arguments for command extension(s)
     if extension:
@@ -64,17 +53,6 @@ def main(*, script_name='ros2', argv=None, description=None, extension=None):
     # parse the command line arguments
     args = parser.parse_args(args=argv)
 
-    if not args.use_python_default_buffering:
-        # Make the output always line buffered.
-        # TextIoWrapper has a reconfigure() method, call that if available.
-        # https://docs.python.org/3/library/io.html#io.TextIOWrapper.reconfigure
-        try:
-            sys.stdout.reconfigure(line_buffering=True)
-        except AttributeError:
-            # if stdout is not a TextIoWrapper instance, or we're using python older than 3.7,
-            # force line buffering by patching print
-            builtins.print = functools.partial(print, flush=True)
-
     if extension is None:
         # get extension identified by the passed command (if available)
         extension = getattr(args, selected_extension_key, None)