wireprotoserver: ensure that output stream gets flushed on exception
Previously flush was happening due to Python finalizer being run on
`BufferedWriter`. With upgrade to Python 3.11 this started randomly
failing.
My guess is that the finalizer on the raw `FileIO` object may
be running before the finalizer of `BufferedWriter` has a chance to run.
At any rate, since we're not relying on finalizers in the happy case
we should also not rely on them in case of exception.
#!/usr/bin/env python3
# Filters traceback lines from stdin.
import io
import sys
if sys.version_info[0] >= 3:
# Prevent \r from being inserted on Windows.
sys.stdout = io.TextIOWrapper(
sys.stdout.buffer,
sys.stdout.encoding,
sys.stdout.errors,
newline="\n",
line_buffering=sys.stdout.line_buffering,
)
state = 'none'
for line in sys.stdin:
if state == 'none':
if line.startswith('Traceback '):
state = 'tb'
elif state == 'tb':
if line.startswith(' File '):
state = 'file'
continue
elif not line.startswith(' '):
state = 'none'
elif not line.replace('^', '').replace('~', '').strip():
# PEP 657: Fine-grained error locations in tracebacks
# ~~~~~~^^^^^^^^^
continue
elif state == 'file':
# Ignore lines after " File "
state = 'tb'
continue
print(line, end='')