#!/usr/bin/env python """ Tests the buffering behavior of stdio streams in `mercurial.utils.procutil`. """ from __future__ import absolute_import import contextlib import errno import os import signal import subprocess import sys import unittest from mercurial import pycompat TEST_BUFFERING_CHILD_SCRIPT = r''' import os from mercurial import dispatch from mercurial.utils import procutil dispatch.initstdio() procutil.{stream}.write(b'aaa') os.write(procutil.{stream}.fileno(), b'[written aaa]') procutil.{stream}.write(b'bbb\n') os.write(procutil.{stream}.fileno(), b'[written bbb\\n]') ''' UNBUFFERED = b'aaa[written aaa]bbb\n[written bbb\\n]' LINE_BUFFERED = b'[written aaa]aaabbb\n[written bbb\\n]' FULLY_BUFFERED = b'[written aaa][written bbb\\n]aaabbb\n' TEST_LARGE_WRITE_CHILD_SCRIPT = r''' import signal import sys from mercurial import dispatch from mercurial.utils import procutil signal.signal(signal.SIGINT, lambda *x: None) dispatch.initstdio() procutil.{stream}.write(b'x' * 1048576) ''' @contextlib.contextmanager def _closing(fds): try: yield finally: for fd in fds: try: os.close(fd) except EnvironmentError: pass @contextlib.contextmanager def _devnull(): devnull = os.open(os.devnull, os.O_WRONLY) with _closing([devnull]): yield (None, devnull) @contextlib.contextmanager def _pipes(): rwpair = os.pipe() with _closing(rwpair): yield rwpair @contextlib.contextmanager def _ptys(): if pycompat.iswindows: raise unittest.SkipTest("PTYs are not supported on Windows") import pty import tty rwpair = pty.openpty() with _closing(rwpair): tty.setraw(rwpair[0]) yield rwpair def _readall(fd, buffer_size, initial_buf=None): buf = initial_buf or [] while True: try: s = os.read(fd, buffer_size) except OSError as e: if e.errno == errno.EIO: # If the child-facing PTY got closed, reading from the # parent-facing PTY raises EIO. break raise if not s: break buf.append(s) return b''.join(buf) class TestStdio(unittest.TestCase): def _test( self, child_script, stream, rwpair_generator, check_output, python_args=[], ): assert stream in ('stdout', 'stderr') with rwpair_generator() as (stream_receiver, child_stream), open( os.devnull, 'rb' ) as child_stdin: proc = subprocess.Popen( [sys.executable] + python_args + ['-c', child_script], stdin=child_stdin, stdout=child_stream if stream == 'stdout' else None, stderr=child_stream if stream == 'stderr' else None, ) try: os.close(child_stream) if stream_receiver is not None: check_output(stream_receiver, proc) except: # re-raises proc.terminate() raise finally: retcode = proc.wait() self.assertEqual(retcode, 0) def _test_buffering( self, stream, rwpair_generator, expected_output, python_args=[] ): def check_output(stream_receiver, proc): self.assertEqual(_readall(stream_receiver, 1024), expected_output) self._test( TEST_BUFFERING_CHILD_SCRIPT.format(stream=stream), stream, rwpair_generator, check_output, python_args, ) def test_buffering_stdout_devnull(self): self._test_buffering('stdout', _devnull, None) def test_buffering_stdout_pipes(self): self._test_buffering('stdout', _pipes, FULLY_BUFFERED) def test_buffering_stdout_ptys(self): self._test_buffering('stdout', _ptys, LINE_BUFFERED) def test_buffering_stdout_devnull_unbuffered(self): self._test_buffering('stdout', _devnull, None, python_args=['-u']) def test_buffering_stdout_pipes_unbuffered(self): self._test_buffering('stdout', _pipes, UNBUFFERED, python_args=['-u']) def test_buffering_stdout_ptys_unbuffered(self): self._test_buffering('stdout', _ptys, UNBUFFERED, python_args=['-u']) if not pycompat.ispy3 and not pycompat.iswindows: # On Python 2 on non-Windows, we manually open stdout in line-buffered # mode if connected to a TTY. We should check if Python was configured # to use unbuffered stdout, but it's hard to do that. test_buffering_stdout_ptys_unbuffered = unittest.expectedFailure( test_buffering_stdout_ptys_unbuffered ) def _test_large_write(self, stream, rwpair_generator, python_args=[]): if not pycompat.ispy3 and pycompat.isdarwin: # Python 2 doesn't always retry on EINTR, but the libc might retry. # So far, it was observed only on macOS that EINTR is raised at the # Python level. As Python 2 support will be dropped soon-ish, we # won't attempt to fix it. raise unittest.SkipTest("raises EINTR on macOS") def check_output(stream_receiver, proc): if not pycompat.iswindows: # On Unix, we can provoke a partial write() by interrupting it # by a signal handler as soon as a bit of data was written. # We test that write() is called until all data is written. buf = [os.read(stream_receiver, 1)] proc.send_signal(signal.SIGINT) else: # On Windows, there doesn't seem to be a way to cause partial # writes. buf = [] self.assertEqual( _readall(stream_receiver, 131072, buf), b'x' * 1048576 ) self._test( TEST_LARGE_WRITE_CHILD_SCRIPT.format(stream=stream), stream, rwpair_generator, check_output, python_args, ) def test_large_write_stdout_devnull(self): self._test_large_write('stdout', _devnull) def test_large_write_stdout_pipes(self): self._test_large_write('stdout', _pipes) def test_large_write_stdout_ptys(self): self._test_large_write('stdout', _ptys) def test_large_write_stdout_devnull_unbuffered(self): self._test_large_write('stdout', _devnull, python_args=['-u']) def test_large_write_stdout_pipes_unbuffered(self): self._test_large_write('stdout', _pipes, python_args=['-u']) def test_large_write_stdout_ptys_unbuffered(self): self._test_large_write('stdout', _ptys, python_args=['-u']) def test_large_write_stderr_devnull(self): self._test_large_write('stderr', _devnull) def test_large_write_stderr_pipes(self): self._test_large_write('stderr', _pipes) def test_large_write_stderr_ptys(self): self._test_large_write('stderr', _ptys) def test_large_write_stderr_devnull_unbuffered(self): self._test_large_write('stderr', _devnull, python_args=['-u']) def test_large_write_stderr_pipes_unbuffered(self): self._test_large_write('stderr', _pipes, python_args=['-u']) def test_large_write_stderr_ptys_unbuffered(self): self._test_large_write('stderr', _ptys, python_args=['-u']) if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)