mirror of
https://github.com/fish-shell/fish-shell
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4ae4314e63
Make it easier to use pexpect and to understand its error messages. Switch to a style in tests using bound methods, which makes them less noisy to write.
319 lines
11 KiB
Python
319 lines
11 KiB
Python
"""pexpect_helper provides a wrapper around the pexpect module.
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This module exposes a single class SpawnedProc, which wraps pexpect.spawn().
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This exposes a pseudo-tty, which fish or another process may talk to.
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The send() function may be used to send data to fish, and the expect_* family
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of functions may be used to match what is output to the tty.
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Example usage:
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sp = SpawnedProc() # this launches fish
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sp.expect_prompt() # wait for a prompt
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sp.sendline("echo hello world")
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sp.expect_prompt("hello world")
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"""
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from __future__ import print_function
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import inspect
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import os
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import os.path
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import re
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import sys
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import time
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import pexpect
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# Default timeout for failing to match.
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TIMEOUT_SECS = 5
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def get_prompt_re(counter):
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""" Return a regular expression for matching a with a given prompt counter. """
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return re.compile(
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r"""(?:\r\n?|^) # beginning of line
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(?:\[.\]\ )? # optional vi mode prompt
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"""
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+ (r"prompt\ %d>" % counter), # prompt with counter
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re.VERBOSE,
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)
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def get_callsite():
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""" Return a triple (filename, line_number, line_text) of the call site location. """
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callstack = inspect.getouterframes(inspect.currentframe())
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for f in callstack:
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if inspect.getmodule(f.frame) is not Message.MODULE:
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return (os.path.basename(f.filename), f.lineno, f.code_context)
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return ("Unknown", -1, "")
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def escape(s):
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""" Escape the string 's' to make it human-understandable. """
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res = []
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for c in s:
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if c == "\n":
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res.append("\\n")
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elif c == "\r":
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res.append("\\r")
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elif c == "\t":
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res.append("\\t")
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elif c.isprintable():
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res.append(c)
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else:
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res.append("\\x{:02x}".format(ord(c)))
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return "".join(res)
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def pexpect_error_type(err):
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""" Return a human-readable description of a pexpect error type. """
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if isinstance(err, pexpect.EOF):
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return "EOF"
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elif isinstance(err, pexpect.TIMEOUT):
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return "timeout"
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else:
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return "unknown error"
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class Message(object):
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""" Some text either sent-to or received-from the spawned proc.
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Attributes:
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dir: the message direction, either DIR_INPUT or DIR_OUTPUT
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filename: the name of the file from which the message was sent
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text: the text of the messages
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when: a timestamp of when the message was sent
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"""
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# Input is input into fish shell ("sent data").
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DIR_INPUT = " INPUT"
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# Output means output from fish shell ("received data").
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DIR_OUTPUT = "OUTPUT"
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MODULE = sys.modules[__name__]
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def __init__(self, dir, text, when):
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""" Construct from a direction, message text and timestamp. """
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self.dir = dir
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self.filename, self.lineno, _ = get_callsite()
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self.text = text
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self.when = when
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@staticmethod
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def sent_input(text, when):
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""" Return an input message with the given text. """
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return Message(Message.DIR_INPUT, text, when)
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@staticmethod
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def received_output(text, when):
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""" Return a output message with the given text. """
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return Message(Message.DIR_OUTPUT, text, when)
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class SpawnedProc(object):
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""" A process, talking to our ptty. This wraps pexpect.spawn.
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Attributes:
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colorize: whether error messages should have ANSI color escapes
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messages: list of Message sent and received, in-order
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start_time: the timestamp of the first message, or None if none yet
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spawn: the pexpect.spawn value
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prompt_counter: the index of the prompt. This cooperates with the fish_prompt
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function to ensure that each printed prompt is distinct.
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"""
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def __init__(self, name="fish", timeout=TIMEOUT_SECS, env=os.environ.copy()):
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""" Construct from a name, timeout, and environment.
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Args:
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name: the name of the executable to launch, as a key into the
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environment dictionary. By default this is 'fish' but may be
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other executables.
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timeout: A timeout to pass to pexpect. This indicates how long to wait
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before giving up on some expected output.
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env: a string->string dictionary, describing the environment variables.
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"""
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if name not in env:
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raise ValueError("'name' variable not found in environment" % name)
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exe_path = env.get(name)
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self.colorize = sys.stdout.isatty()
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self.messages = []
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self.start_time = None
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self.spawn = pexpect.spawn(exe_path, env=env, encoding="utf-8", timeout=timeout)
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self.spawn.delaybeforesend = None
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self.prompt_counter = 1
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def time_since_first_message(self):
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""" Return a delta in seconds since the first message, or 0 if this is the first. """
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now = time.monotonic()
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if not self.start_time:
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self.start_time = now
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return now - self.start_time
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def send(self, s):
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""" Cover over pexpect.spawn.send().
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Send the given string to the tty, returning the number of bytes written.
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"""
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res = self.spawn.send(s)
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when = self.time_since_first_message()
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self.messages.append(Message.sent_input(s, when))
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return res
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def sendline(self, s):
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""" Cover over pexpect.spawn.sendline().
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Send the given string + linesep to the tty, returning the number of bytes written.
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"""
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return self.send(s + os.linesep)
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def expect_re(self, pat, pat_desc=None, unmatched=None, **kwargs):
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""" Cover over pexpect.spawn.expect().
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Consume all "new" output of self.spawn until the given pattern is matched, or
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the timeout is reached.
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Note that output between the current position and the location of the match is
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consumed as well.
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The pattern is typically a regular expression in string form, but may also be
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any of the types accepted by pexpect.spawn.expect().
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If the 'unmatched' parameter is given, it is printed as part of the error message
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of any failure.
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On failure, this prints an error and exits.
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"""
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try:
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res = self.spawn.expect(pat, **kwargs)
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when = self.time_since_first_message()
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self.messages.append(
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Message.received_output(self.spawn.match.group(), when)
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)
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return res
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except pexpect.ExceptionPexpect as err:
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if not pat_desc:
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pat_desc = str(pat)
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self.report_exception_and_exit(pat_desc, unmatched, err)
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def expect_str(self, s, **kwargs):
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""" Cover over expect_re() which accepts a literal string. """
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return self.expect_re(re.escape(s), **kwargs)
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def expect_prompt(self, *args, **kwargs):
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""" Convenience function which matches some text and then a prompt.
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Match the given positional arguments as expect_re, and then look
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for a prompt, bumping the prompt counter.
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Returns None on success, and exits on failure.
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Example:
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sp.sendline("echo hello world")
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sp.expect_prompt("hello world")
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"""
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if args:
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self.expect_re(*args, **kwargs)
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self.expect_re(
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get_prompt_re(self.prompt_counter),
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pat_desc="prompt %d" % self.prompt_counter,
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)
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self.prompt_counter += 1
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def report_exception_and_exit(self, pat, unmatched, err):
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""" Things have gone badly.
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We have an exception 'err', some pexpect.ExceptionPexpect.
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Report it to stdout, along with the offending call site.
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If 'unmatched' is set, print it to stdout.
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"""
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colors = self.colors()
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failtype = pexpect_error_type(err)
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fmtkeys = {"failtype": failtype, "pat": escape(pat)}
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fmtkeys.update(**colors)
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filename, lineno, code_context = get_callsite()
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fmtkeys["filename"] = filename
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fmtkeys["lineno"] = lineno
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fmtkeys["code"] = "\n".join(code_context)
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if unmatched:
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print(
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"{RED}Error: {NORMAL}{BOLD}{unmatched}{RESET}".format(
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unmatched=unmatched, **fmtkeys
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)
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)
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print(
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"{RED}Failed to match pattern:{NORMAL} {BOLD}{pat}{RESET}".format(**fmtkeys)
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)
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print(
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"{filename}:{lineno}: {BOLD}{failtype}{RESET} from {code}".format(**fmtkeys)
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)
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print("")
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print("{CYAN}Escaped buffer:{RESET}".format(**colors))
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print(escape(self.spawn.before))
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print("")
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if sys.stdout.isatty():
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print(
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"{CYAN}When written to the tty, this looks like:{RESET}".format(
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**colors
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)
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)
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print("{CYAN}<-------{RESET}".format(**colors))
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sys.stdout.write(self.spawn.before)
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sys.stdout.flush()
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print("{RESET}\n{CYAN}------->{RESET}".format(**colors))
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print("")
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# Show the last 5 messages.
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print("Last 5 messages:")
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delta = None
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for m in self.messages[-5:]:
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etext = escape(m.text)
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timestamp = m.when * 1000.0
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# Use relative timestamps and add a sign.
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# This assumes a max length of 10^10 milliseconds (115 days) for the initial timestamp,
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# and 11.5 days for the delta.
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if delta:
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timestamp -= delta
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timestampstr = "{timestamp:+10.2f} ms".format(timestamp=timestamp)
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else:
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timestampstr = "{timestamp:10.2f} ms".format(timestamp=timestamp)
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delta = m.when * 1000.0
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dir = m.dir
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print(
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"{dir} {timestampstr} (Line {lineno}): {BOLD}{etext}{RESET}".format(
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dir=m.dir,
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timestampstr=timestampstr,
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filename=m.filename,
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lineno=m.lineno,
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etext=etext,
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**colors
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)
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)
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print("")
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sys.exit(1)
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def sleep(self, secs):
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""" Cover over time.sleep(). """
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time.sleep(secs)
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def colors(self):
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""" Return a dictionary mapping color names to ANSI escapes """
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def ansic(n):
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""" Return either an ANSI escape sequence for a color, or empty string. """
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return "\033[%dm" % n if self.colorize else ""
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return {
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"RESET": ansic(0),
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"BOLD": ansic(1),
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"NORMAL": ansic(39),
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"BLACK": ansic(30),
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"RED": ansic(31),
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"GREEN": ansic(32),
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"YELLOW": ansic(33),
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"BLUE": ansic(34),
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"MAGENTA": ansic(35),
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"CYAN": ansic(36),
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"LIGHTGRAY": ansic(37),
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"DARKGRAY": ansic(90),
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"LIGHTRED": ansic(91),
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"LIGHTGREEN": ansic(92),
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"LIGHTYELLOW": ansic(93),
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"LIGHTBLUE": ansic(94),
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"LIGHTMAGENTA": ansic(95),
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"LIGHTCYAN": ansic(96),
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"WHITE": ansic(97),
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}
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