tests/filterpyflakes.py

ui: flush stderr after printing a non-chained exception for Windows

There were consistent test failures in test-bad-extension.t, because Windows
buffers stderr when redirected to a file (per the comment in ui.write_err()).
That resulted in failures like this:

  --- c:/Users/Matt/Projects/hg/tests/test-bad-extension.t
  +++ c:/Users/Matt/Projects/hg/tests/test-bad-extension.t.err
  @@ -23,11 +23,11 @@
     Traceback (most recent call last):
     Exception: bit bucket overflow
     *** failed to import extension badext2: No module named badext2
  -  Traceback (most recent call last):
  -  ImportError: No module named badext2
     hg help [-ec] [TOPIC]

     show help for a given topic or a help overview
  +  Traceback (most recent call last):
  +  ImportError: No module named badext2

   show traceback for ImportError of hgext.name if debug is set
   (note that --debug option isn't applied yet when loading extensions)

Instead of inserting another flush immediately after the print, to go along with
the one recently added prior to the print (see 3ff4b07412ad), funnel the output
through ui.write_err().  The flush prior to printing the traceback only mentions
that stdout needs to be flushed, and only stderr needs to be flushed after
printing the traceback.  ui.write_err() does both for us without needing to
redocument the quirky Windows behavior.  It will also clear any progress bar.

#!/usr/bin/env python

# Filter output by pyflakes to control which warnings we check

import sys, re, os

def makekey(typeandline):
    """
    for sorting lines by: msgtype, path/to/file, lineno, message

    typeandline is a sequence of a message type and the entire message line
    the message line format is path/to/file:line: message

    >>> makekey((3, 'example.py:36: any message'))
    (3, 'example.py', 36, ' any message')
    >>> makekey((7, 'path/to/file.py:68: dummy message'))
    (7, 'path/to/file.py', 68, ' dummy message')
    >>> makekey((2, 'fn:88: m')) > makekey((2, 'fn:9: m'))
    True
    """

    msgtype, line = typeandline
    fname, line, message = line.split(":", 2)
    # line as int for ordering 9 before 88
    return msgtype, fname, int(line), message


lines = []
for line in sys.stdin:
    # We whitelist tests (see more messages in pyflakes.messages)
    pats = [
            (r"imported but unused", None),
            (r"local variable '.*' is assigned to but never used", None),
            (r"unable to detect undefined names", None),
            (r"undefined name '.*'",
             r"undefined name '(WindowsError|memoryview)'")
           ]

    for msgtype, (pat, excl) in enumerate(pats):
        if re.search(pat, line) and (not excl or not re.search(excl, line)):
            break # pattern matches
    else:
        continue # no pattern matched, next line
    fn = line.split(':', 1)[0]
    f = open(os.path.join(os.path.dirname(os.path.dirname(__file__)), fn))
    data = f.read()
    f.close()
    if 'no-' 'check-code' in data:
        continue
    lines.append((msgtype, line))

for msgtype, line in sorted(lines, key=makekey):
    sys.stdout.write(line)
print

# self test of "undefined name" detection for other than 'memoryview'
if False:
    print undefinedname