#6719 prettifying pants tracebacks Issue created by cosmicexplorer @ShaneDelmore noted this cli output this morning:

> pants list --type=scala_library ::
timestamp: 2018-11-02T09:35:30.912793
Exception caught: (pants.option.errors.ParseError)
  File "/Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl/pants/bin/daemon_pants_runner.py", line 320, in post_fork_child
    self._options_bootstrapper
  File "/Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl/pants/bin/local_pants_runner.py", line 95, in create
    options.for_scope(scope)
  File "/Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl/pants/option/options.py", line 401, in for_scope
    self._parser_hierarchy.get_parser_by_scope(scope).parse_args(flags_in_scope, values)
  File "/Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl/pants/option/parser.py", line 225, in parse_args
    self._scope_str(), ', '.join(flag_value_map.keys())))

Exception message: Unrecognized command line flags on scope 'list': --type

While it's perfectly reasonable to use the traceback that python gives us, we probably have the opportunity to clean it up a bit and convert (in this case)

/Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl/pants/option/parser.py

to (potentially) something that doesn't have the wheel path in it, which might look something like:

> pants list --type=scala_library ::
timestamp: 2018-11-02T09:35:30.912793
pants is located in: /Users/sdelmore/.pex/install/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl.545e36657048c66e803f821fe09b152f4e558d92/pantsbuild.pants-1.11.0rc0+f9a61c0c-cp27-none-macosx_10_11_x86_64.whl
Exception caught: (pants.option.errors.ParseError)
  File ".../pants/bin/daemon_pants_runner.py", line 320, in post_fork_child
    self._options_bootstrapper
  File ".../pants/bin/local_pants_runner.py", line 95, in create
    options.for_scope(scope)
  File ".../pants/option/options.py", line 401, in for_scope
    self._parser_hierarchy.get_parser_by_scope(scope).parse_args(flags_in_scope, values)
  File ".../pants/option/parser.py", line 225, in parse_args
    self._scope_str(), ', '.join(flag_value_map.keys())))

Exception message: Unrecognized command line flags on scope 'list': --type

Note the single location at the top, making the subsequent traceback much neater. I'm thinking we could do this very easily in the

sys.excepthook

we set in

ExceptionSink

by manipulating the traceback to find stack frames within the pants pex, simplifying them, then displaying the location at the top of the traceback as above. pantsbuild/pants