get_executable_lines_for_file crashes for not compiling files

[jsoref]

I'm in the middle of merging mercurial, so I have merge conflicts. I also am debugging it (albeit with a different hg).

(py)[timeless@gcc2-power8 crew8]$ ./hg --cwd ../crew summary --debugger
entering debugger - type c to continue starting hg or h for help
Traceback (most recent call last):
  File "/home/timeless/hg/crew8/mercurial/dispatch.py", line 202, in _runcatch
    debugtrace[debugger]()
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/__init__.py", line 150, in set_trace
    dbg = _get_debugger()
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/__init__.py", line 35, in _get_debugger
    dbg = Debugger(**kwargs)
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/debugger.py", line 165, in __init__
    for bpoint_descr in load_breakpoints():
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/settings.py", line 482, in load_breakpoints
    return parse_breakpoints(lines)
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/settings.py", line 448, in parse_breakpoints
    if get_breakpoint_invalid_reason(filename, lineno) is None:
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/lowlevel.py", line 46, in get_breakpoint_invalid_reason
    if lineno not in get_executable_lines_for_file(filename):
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/lowlevel.py", line 23, in get_executable_lines_for_file
    codes = [compile("".join(getlines(filename)), filename, "exec")]
  File "/home/timeless/hg/crew/mercurial/util.py", line 443
    <<<<<<< local
     ^
SyntaxError: invalid syntax
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 2.7.8 (default, Jul  8 2015, 18:13:08) [GCC 4.9.2 20150212 (Red Hat 4.9.2-6)]
** Mercurial Distributed SCM (version 3.7.3+808-62879c5a749b+20160413)
** Extensions loaded:
Traceback (most recent call last):
  File "./hg", line 43, in <module>
    mercurial.dispatch.run()
  File "/home/timeless/hg/crew8/mercurial/dispatch.py", line 59, in run
    sys.exit((dispatch(request(sys.argv[1:])) or 0) & 255)
  File "/home/timeless/hg/crew8/mercurial/dispatch.py", line 125, in dispatch
    ret = _runcatch(req)
  File "/home/timeless/hg/crew8/mercurial/dispatch.py", line 211, in _runcatch
    debugmortem[debugger](sys.exc_info()[2])
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/__init__.py", line 215, in post_mortem
    dbg = _get_debugger()
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/__init__.py", line 35, in _get_debugger
    dbg = Debugger(**kwargs)
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/debugger.py", line 165, in __init__
    for bpoint_descr in load_breakpoints():
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/settings.py", line 482, in load_breakpoints
    return parse_breakpoints(lines)
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/settings.py", line 448, in parse_breakpoints
    if get_breakpoint_invalid_reason(filename, lineno) is None:
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/lowlevel.py", line 46, in get_breakpoint_invalid_reason
    if lineno not in get_executable_lines_for_file(filename):
  File "/home/timeless/hg/py/lib/python2.7/site-packages/pudb-2015.4.2-py2.7.egg/pudb/lowlevel.py", line 23, in get_executable_lines_for_file
    codes = [compile("".join(getlines(filename)), filename, "exec")]
  File "/home/timeless/hg/crew/mercurial/util.py", line 443
    <<<<<<< local
     ^
SyntaxError: invalid syntax

get_executable_lines_for_file needs to use a try block for compile

[asmeurer]

Perhaps it would make more sense to put the try block in load_breakpoints.

[jsoref]

I think load_breakpoints is too late, we wouldn't want to lose the other breakpoints from other files.
but you're right, get_executable_lines_for_file is too deep.