old_contents: #!/usr/bin/python
  # produces cleaner build.json files
  
  import collections
  import json
  import os
  import sys
  
  _TOP_LEVEL_KEYS = ['settings', 'filegroups', 'libs', 'targets']
  _VERSION_KEYS = ['major', 'minor', 'micro', 'build']
  _ELEM_KEYS = [
      'name', 
      'build', 
      'language', 
      'public_headers', 
      'headers', 
      'src', 
      'deps']
  
  def rebuild_as_ordered_dict(indict, special_keys):
    outdict = collections.OrderedDict()
    for key in special_keys:
      if key in indict:
        outdict[key] = indict[key]
    for key in sorted(indict.keys()):
      if key in special_keys: continue
      outdict[key] = indict[key]
    return outdict
  
  def clean_elem(indict):
    for name in ['public_headers', 'headers', 'src']:
      if name not in indict: continue
      inlist = indict[name]
      protos = set(x for x in inlist if os.path.splitext(x)[1] == '.proto')
      others = set(x for x in inlist if x not in protos)
      indict[name] = sorted(protos) + sorted(others)
    return rebuild_as_ordered_dict(indict, _ELEM_KEYS)
  
  for filename in sys.argv[1:]:
    with open(filename) as f:
      js = json.load(f)
    js = rebuild_as_ordered_dict(js, _TOP_LEVEL_KEYS)
    js['settings']['version'] = rebuild_as_ordered_dict(
        js['settings']['version'], _VERSION_KEYS)
    for grp in ['filegroups', 'libs', 'targets']:
      if grp not in js: continue
      js[grp] = sorted([clean_elem(x) for x in js[grp]],
                       key=lambda x: (x.get('language', '_'), x['name']))
    output = json.dumps(js, indent = 2)
    # massage out trailing whitespace
    lines = []
    for line in output.splitlines():
      lines.append(line.rstrip() + '\n')
    with open(filename, 'w') as f:
      f.write(''.join(lines))
  
  
new_contents: #!/usr/bin/python
  # produces cleaner build.json files
  
  import collections
  import json
  import os
  import sys
  
  TEST = (os.environ.get('TEST', 'false') == 'true')
  
  _TOP_LEVEL_KEYS = ['settings', 'filegroups', 'libs', 'targets']
  _VERSION_KEYS = ['major', 'minor', 'micro', 'build']
  _ELEM_KEYS = [
      'name', 
      'build', 
      'language', 
      'public_headers', 
      'headers', 
      'src', 
      'deps']
  
  def rebuild_as_ordered_dict(indict, special_keys):
    outdict = collections.OrderedDict()
    for key in special_keys:
      if key in indict:
        outdict[key] = indict[key]
    for key in sorted(indict.keys()):
      if key in special_keys: continue
      outdict[key] = indict[key]
    return outdict
  
  def clean_elem(indict):
    for name in ['public_headers', 'headers', 'src']:
      if name not in indict: continue
      inlist = indict[name]
      protos = set(x for x in inlist if os.path.splitext(x)[1] == '.proto')
      others = set(x for x in inlist if x not in protos)
      indict[name] = sorted(protos) + sorted(others)
    return rebuild_as_ordered_dict(indict, _ELEM_KEYS)
  
  for filename in sys.argv[1:]:
    with open(filename) as f:
      js = json.load(f)
    js = rebuild_as_ordered_dict(js, _TOP_LEVEL_KEYS)
    js['settings']['version'] = rebuild_as_ordered_dict(
        js['settings']['version'], _VERSION_KEYS)
    for grp in ['filegroups', 'libs', 'targets']:
      if grp not in js: continue
      js[grp] = sorted([clean_elem(x) for x in js[grp]],
                       key=lambda x: (x.get('language', '_'), x['name']))
    output = json.dumps(js, indent = 2)
    # massage out trailing whitespace
    lines = []
    for line in output.splitlines():
      lines.append(line.rstrip() + '\n')
    output = ''.join(lines)
    if TEST:
      with open(filename) as f:
        assert f.read() == output
    else:
      with open(filename, 'w') as f:
        f.write(output)
  
  
subject: Add ability to test