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diff --git a/third_party/py/abseil/absl/app.py b/third_party/py/abseil/absl/app.py
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+++ b/third_party/py/abseil/absl/app.py
@@ -0,0 +1,390 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Generic entry point for Abseil Python applications.
+
+To use this module, define a 'main' function with a single 'argv' argument and
+call app.run(main). For example:
+
+def main(argv):
+  del argv  # Unused.
+
+if __name__ == '__main__':
+  app.run(main)
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import errno
+import os
+import pdb
+import sys
+import traceback
+
+from absl import command_name
+from absl import flags
+from absl import logging
+
+try:
+  import faulthandler
+except ImportError:
+  faulthandler = None
+
+
+FLAGS = flags.FLAGS
+
+flags.DEFINE_boolean('run_with_pdb', False, 'Set to true for PDB debug mode')
+flags.DEFINE_boolean('pdb_post_mortem', False,
+                     'Set to true to handle uncaught exceptions with PDB '
+                     'post mortem.')
+flags.DEFINE_boolean('run_with_profiling', False,
+                     'Set to true for profiling the script. '
+                     'Execution will be slower, and the output format might '
+                     'change over time.')
+flags.DEFINE_string('profile_file', None,
+                    'Dump profile information to a file (for python -m '
+                    'pstats). Implies --run_with_profiling.')
+flags.DEFINE_boolean('use_cprofile_for_profiling', True,
+                     'Use cProfile instead of the profile module for '
+                     'profiling. This has no effect unless '
+                     '--run_with_profiling is set.')
+flags.DEFINE_boolean('only_check_args', False,
+                     'Set to true to validate args and exit.',
+                     allow_hide_cpp=True)
+
+
+
+# If main() exits via an abnormal exception, call into these
+# handlers before exiting.
+EXCEPTION_HANDLERS = []
+
+
+class Error(Exception):
+  pass
+
+
+class UsageError(Error):
+  """Exception raised when the arguments supplied by the user are invalid.
+
+  Raise this when the arguments supplied are invalid from the point of
+  view of the application. For example when two mutually exclusive
+  flags have been supplied or when there are not enough non-flag
+  arguments. It is distinct from flags.Error which covers the lower
+  level of parsing and validating individual flags.
+  """
+
+  def __init__(self, message, exitcode=1):
+    super(UsageError, self).__init__(message)
+    self.exitcode = exitcode
+
+
+class HelpFlag(flags.BooleanFlag):
+  """Special boolean flag that displays usage and raises SystemExit."""
+  NAME = 'help'
+  SHORT_NAME = '?'
+
+  def __init__(self):
+    super(HelpFlag, self).__init__(
+        self.NAME, False, 'show this help',
+        short_name=self.SHORT_NAME, allow_hide_cpp=True)
+
+  def parse(self, arg):
+    if arg:
+      usage(shorthelp=True, writeto_stdout=True)
+      # Advertise --helpfull on stdout, since usage() was on stdout.
+      print()
+      print('Try --helpfull to get a list of all flags.')
+      sys.exit(1)
+
+
+class HelpshortFlag(HelpFlag):
+  """--helpshort is an alias for --help."""
+  NAME = 'helpshort'
+  SHORT_NAME = None
+
+
+class HelpfullFlag(flags.BooleanFlag):
+  """Display help for flags in this module and all dependent modules."""
+
+  def __init__(self):
+    super(HelpfullFlag, self).__init__(
+        'helpfull', False, 'show full help', allow_hide_cpp=True)
+
+  def parse(self, arg):
+    if arg:
+      usage(writeto_stdout=True)
+      sys.exit(1)
+
+
+class HelpXMLFlag(flags.BooleanFlag):
+  """Similar to HelpfullFlag, but generates output in XML format."""
+
+  def __init__(self):
+    super(HelpXMLFlag, self).__init__(
+        'helpxml', False, 'like --helpfull, but generates XML output',
+        allow_hide_cpp=True)
+
+  def parse(self, arg):
+    if arg:
+      flags.FLAGS.write_help_in_xml_format(sys.stdout)
+      sys.exit(1)
+
+
+def parse_flags_with_usage(args):
+  """Tries to parse the flags, print usage, and exit if unparseable.
+
+  Args:
+    args: [str], a non-empty list of the command line arguments including
+        program name.
+
+  Returns:
+    [str], a non-empty list of remaining command line arguments after parsing
+    flags, including program name.
+  """
+  try:
+    return FLAGS(args)
+  except flags.Error as error:
+    sys.stderr.write('FATAL Flags parsing error: %s\n' % error)
+    sys.stderr.write('Pass --helpshort or --helpfull to see help on flags.\n')
+    sys.exit(1)
+
+
+_define_help_flags_called = False
+
+
+def define_help_flags():
+  """Registers help flags. Idempotent."""
+  # Use a global to ensure idempotence.
+  global _define_help_flags_called
+
+  if not _define_help_flags_called:
+    flags.DEFINE_flag(HelpFlag())
+    flags.DEFINE_flag(HelpshortFlag())  # alias for --help
+    flags.DEFINE_flag(HelpfullFlag())
+    flags.DEFINE_flag(HelpXMLFlag())
+    _define_help_flags_called = True
+
+
+def register_and_parse_flags_with_usage(argv=None):
+  """Registers help flags, parses arguments and shows usage if appropriate.
+
+  This also calls sys.exit(0) if flag --only_check_args is True.
+
+  Args:
+    argv: [str], a non-empty list of the command line arguments including
+        program name, sys.argv is used if None.
+
+  Returns:
+    [str], a non-empty list of remaining command line arguments after parsing
+    flags, including program name.
+  """
+  define_help_flags()
+
+  argv = parse_flags_with_usage(sys.argv if argv is None else argv)
+  # Exit when told so.
+  if FLAGS.only_check_args:
+    sys.exit(0)
+  # Immediately after flags are parsed, bump verbosity to INFO if the flag has
+  # not been set.
+  if FLAGS['verbosity'].using_default_value:
+    FLAGS.verbosity = 0
+  return argv
+
+
+def _run_main(main, argv):
+  """Calls main, optionally with pdb or profiler."""
+  if FLAGS.run_with_pdb:
+    sys.exit(pdb.runcall(main, argv))
+  elif FLAGS.run_with_profiling or FLAGS.profile_file:
+    # Avoid import overhead since most apps (including performance-sensitive
+    # ones) won't be run with profiling.
+    import atexit
+    if FLAGS.use_cprofile_for_profiling:
+      import cProfile as profile
+    else:
+      import profile
+    profiler = profile.Profile()
+    if FLAGS.profile_file:
+      atexit.register(profiler.dump_stats, FLAGS.profile_file)
+    else:
+      atexit.register(profiler.print_stats)
+    retval = profiler.runcall(main, argv)
+    sys.exit(retval)
+  else:
+    sys.exit(main(argv))
+
+
+def _call_exception_handlers(exception):
+  """Calls any installed exception handlers."""
+  for handler in EXCEPTION_HANDLERS:
+    try:
+      if handler.wants(exception):
+        handler.handle(exception)
+    except:  # pylint: disable=bare-except
+      try:
+        # We don't want to stop for exceptions in the exception handlers but
+        # we shouldn't hide them either.
+        logging.error(traceback.format_exc())
+      except:  # pylint: disable=bare-except
+        # In case even the logging statement fails, ignore.
+        pass
+
+
+def run(main, argv=None):
+  """Begins executing the program.
+
+  Args:
+    main: The main function to execute. It takes an single argument "argv",
+        which is a list of command line arguments with parsed flags removed.
+    argv: A non-empty list of the command line arguments including program name,
+        sys.argv is used if None.
+  - Parses command line flags with the flag module.
+  - If there are any errors, prints usage().
+  - Calls main() with the remaining arguments.
+  - If main() raises a UsageError, prints usage and the error message.
+  """
+  try:
+    argv = _run_init(sys.argv if argv is None else argv)
+    try:
+      _run_main(main, argv)
+    except UsageError as error:
+      usage(shorthelp=True, detailed_error=error, exitcode=error.exitcode)
+    except:
+      if FLAGS.pdb_post_mortem:
+        traceback.print_exc()
+        pdb.post_mortem()
+      raise
+  except Exception as e:
+    _call_exception_handlers(e)
+    raise
+
+
+def _run_init(argv):
+  """Does one-time initialization and re-parses flags on rerun."""
+  if _run_init.done:
+    return parse_flags_with_usage(argv)
+  command_name.make_process_name_useful()
+  # Set up absl logging handler.
+  logging.use_absl_handler()
+  argv = register_and_parse_flags_with_usage(argv=argv)
+  if faulthandler:
+    try:
+      faulthandler.enable()
+    except Exception:  # pylint: disable=broad-except
+      # Some tests verify stderr output very closely, so don't print anything.
+      # Disabled faulthandler is a low-impact error.
+      pass
+  _run_init.done = True
+  return argv
+
+
+_run_init.done = False
+
+
+def usage(shorthelp=False, writeto_stdout=False, detailed_error=None,
+          exitcode=None):
+  """Writes __main__'s docstring to stderr with some help text.
+
+  Args:
+    shorthelp: bool, if True, prints only flags from this module,
+        rather than all flags.
+    writeto_stdout: bool, if True, writes help message to stdout,
+        rather than to stderr.
+    detailed_error: str, additional detail about why usage info was presented.
+    exitcode: optional integer, if set, exits with this status code after
+        writing help.
+  """
+  if writeto_stdout:
+    stdfile = sys.stdout
+  else:
+    stdfile = sys.stderr
+
+  doc = sys.modules['__main__'].__doc__
+  if not doc:
+    doc = '\nUSAGE: %s [flags]\n' % sys.argv[0]
+    doc = flags.text_wrap(doc, indent='       ', firstline_indent='')
+  else:
+    # Replace all '%s' with sys.argv[0], and all '%%' with '%'.
+    num_specifiers = doc.count('%') - 2 * doc.count('%%')
+    try:
+      doc %= (sys.argv[0],) * num_specifiers
+    except (OverflowError, TypeError, ValueError):
+      # Just display the docstring as-is.
+      pass
+  if shorthelp:
+    flag_str = FLAGS.main_module_help()
+  else:
+    flag_str = str(FLAGS)
+  try:
+    stdfile.write(doc)
+    if flag_str:
+      stdfile.write('\nflags:\n')
+      stdfile.write(flag_str)
+    stdfile.write('\n')
+    if detailed_error is not None:
+      stdfile.write('\n%s\n' % detailed_error)
+  except IOError as e:
+    # We avoid printing a huge backtrace if we get EPIPE, because
+    # "foo.par --help | less" is a frequent use case.
+    if e.errno != errno.EPIPE:
+      raise
+  if exitcode is not None:
+    sys.exit(exitcode)
+
+
+class ExceptionHandler(object):
+  """Base exception handler from which other may inherit."""
+
+  def wants(self, exc):
+    """Returns whether this handler wants to handle the exception or not.
+
+    This base class returns True for all exceptions by default. Override in
+    subclass if it wants to be more selective.
+
+    Args:
+      exc: Exception, the current exception.
+    """
+    del exc  # Unused.
+    return True
+
+  def handle(self, exc):
+    """Do something with the current exception.
+
+    Args:
+      exc: Exception, the current exception
+
+    This method must be overridden.
+    """
+    raise NotImplementedError()
+
+
+def install_exception_handler(handler):
+  """Installs an exception handler.
+
+  Args:
+    handler: ExceptionHandler, the exception handler to install.
+
+  Raises:
+    TypeError: Raised when the handler was not of the correct type.
+
+  All installed exception handlers will be called if main() exits via
+  an abnormal exception, i.e. not one of SystemExit, KeyboardInterrupt,
+  FlagsError or UsageError.
+  """
+  if not isinstance(handler, ExceptionHandler):
+    raise TypeError('handler of type %s does not inherit from ExceptionHandler'
+                    % type(handler))
+  EXCEPTION_HANDLERS.append(handler)