Use repr() to pretty print because it can handle arbitrary bytes.

json.dumps() crashes on invalid utf-8.

asdl/format.py

@@ -316,13 +316,18 @@ def MakeTree(obj, abbrev_hook=None, omit_empty=True):
# This is word characters, - and _, as well as path name characters . and /.
_PLAIN_RE = re.compile(r'^[a-zA-Z0-9\-_./]+$')

# NOTE: Turning JSON back on can be a cheap hack for detecting invalid unicode.
# But we want to write our own AST walker for that.

def _PrettyString(s):
  if '\n' in s:
    return json.dumps(s)  # account for the fact that $ matches the newline
    #return json.dumps(s)  # account for the fact that $ matches the newline
    return repr(s)
  if _PLAIN_RE.match(s):
    return s
  else:
    return json.dumps(s)
    #return json.dumps(s)
    return repr(s)


INDENT = 2