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add essential file drop from last 3 commits
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‎explain_output_difference.py

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import os, re
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# Expected output has been supplied as an environment variable
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# and the program has been stoped because the output was incorrect
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def explain_output_difference(loc, output_stream, color):
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# autotest may try to print all errors in red, so disable this
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print(color('', 'black'), end='', file=output_stream)
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explain_output_difference1(loc, output_stream, color)
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print(file=output_stream)
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def explain_output_difference1(loc, output_stream, color):
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# values supplied for expected output for this execution
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expected_stdout = os.environb.get(b'DCC_EXPECTED_STDOUT', '')
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# ignore_case = getenv_boolean('DCC_IGNORE_CASE')
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# ignore_empty_lines = getenv_boolean('DCC_IGNORE_EMPTY_LINES')
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ignore_trailing_white_space = getenv_boolean('DCC_IGNORE_TRAILING_WHITE_SPACE', default=True)
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# compare_only_characters = os.environ.get('DCC_COMPARE_ONLY_CHARACTERS')
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# value describing discrepency between actual and expected output
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reason = os.environ.get('DCC_OUTPUT_ERROR', '')
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line_number = getenv_int('DCC_ACTUAL_LINE_NUMBER')
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# these values do not include current line
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n_expected_bytes_seen = getenv_int('DCC_N_EXPECTED_BYTES_SEEN')
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n_actual_bytes_seen = getenv_int('DCC_N_ACTUAL_BYTES_SEEN')
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expected_line = os.environb.get(b'DCC_EXPECTED_LINE', '')
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actual_line = os.environb.get(b'DCC_ACTUAL_LINE', '')
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expected_column = getenv_int('DCC_EXPECTED_COLUMN')
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actual_column = getenv_int('DCC_ACTUAL_COLUMN')
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if 0 <= actual_column < len(actual_line):
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actual_char = actual_line[actual_column]
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else:
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actual_char = None
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if ignore_trailing_white_space and expected_stdout[-1:] == b'\n':
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expected_stdout = expected_stdout.rstrip() + b'\n'
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n_expected_lines = len(expected_stdout.splitlines())
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is_last_expected_line = n_expected_bytes_seen + len(expected_line) >= len(expected_stdout)
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if 0 <= expected_column < len(expected_line):
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expected_byte = expected_line[expected_column:expected_column+1]
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else:
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expected_byte = None
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# primary = lambda text, **kwargs: color(text, style='bold', **kwargs)
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danger = lambda text, **kwargs: color(text, fg='red', style='bold', **kwargs)
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success = lambda text, **kwargs: color(text, fg='green', style='bold', **kwargs)
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# info = lambda text, **kwargs: color(text, fg='cyan', style='bold', **kwargs)
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if not actual_line.endswith(b"\n"):
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print("Execution failed because ", end='', file=output_stream)
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else:
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print("Execution stopped because ", end='', file=output_stream)
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if reason == "expected line too long":
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print("internal error: expected line too long", file=output_stream)
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return
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if reason == "line too long":
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print("program wrote", danger("a line containing over " + str(actual_column) + " bytes."), file=output_stream)
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print("Do you have an infinite loop?", file=output_stream)
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print_line(actual_line, "start of the", danger, output_stream)
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return
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if reason == "too much output":
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print("program produced", danger("too much output."), file=output_stream)
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print("Your program printed", actual_column, "bytes.")
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print("Do you have an infinite loop?", file=output_stream)
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print_line(actual_line, "last", danger, output_stream)
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return
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if reason == "zero byte":
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print("a", danger("zero byte ('\\0')"), "was printed.", file=output_stream)
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print("Byte", actual_column, "of line", line_number, "of program's output was a zero byte ('\\0')", file=output_stream)
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if len(expected_line):
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print("Here are the characters on the line before the zero byte:", file=output_stream)
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print(sanitize(actual_line), file=output_stream)
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print("\nFor more information go to:", explanation_url("zero_byte"), file=output_stream)
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return
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if n_actual_bytes_seen == 0 and len(actual_line) == 0:
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print("program produced", danger("no output."), file=output_stream)
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print(n_expected_lines, "lines of output were expected", file=output_stream)
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print_line(expected_line, "first expected", success, output_stream)
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return
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if len(actual_line) == 0:
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print("of", danger("missing output lines."), file=output_stream)
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print("Your program printed", line_number, "lines of correct output but stopped before printing all the expected output.", file=output_stream)
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print_line(expected_line, "next expected", success, output_stream)
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return
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if n_expected_bytes_seen == 0 and len(expected_line) == 0:
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print("program produced", danger("output when no output was expected."), file=output_stream)
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print_line(actual_line, "unexpected", danger, output_stream)
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return
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if len(expected_line) == 0:
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print("of", danger("unexpected extra output."), file=output_stream)
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print("The program produced all the expected output and then produced extra output.", file=output_stream)
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print_line(actual_line, "extra", danger, output_stream)
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return
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if is_last_expected_line and expected_byte == b'\n' and actual_char is None:
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print('the last', danger("newline was missing."), file=output_stream)
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print("Your program produced all the expected output, except the last newline ('\\n') was missing.", file=output_stream)
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print("\nFor more information go to", explanation_url("missing_newline"), file=output_stream)
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return
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show_line_length = max(len(expected_line) + 8, 80)
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bad_characters_explanation = check_bad_characters(actual_line, line_number, danger, expected_line)
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if bad_characters_explanation:
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print(bad_characters_explanation, end='', file=output_stream)
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return
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print("of an", danger('incorrect output line.'), file=output_stream)
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print('Byte', actual_column + 1, 'of line', line_number, "of program output was incorrect.", file=output_stream)
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if not actual_line[actual_column+1:]:
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if actual_line.rstrip(b'\n') + expected_byte == expected_line.rstrip(b'\n'):
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print("A", "'" + danger(sanitize(expected_byte)) + "'", "was missing from the end of the output line.", file=output_stream)
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else:
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print("The characters you printed were correct, but more characters were expected.", file=output_stream)
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print("The correct output line was:", file=output_stream)
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print(success(sanitize(expected_line, max_line_length_shown=show_line_length)), file=output_stream)
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print("Your program printed this line:", file=output_stream)
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correct_prefix = success(sanitize(actual_line[0:actual_column]))
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print(correct_prefix, end='', file=output_stream)
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incorrect_byte = actual_line[actual_column:actual_column + 1]
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if incorrect_byte == ' ':
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print(danger(sanitize(incorrect_byte), bg='red'), end='', file=output_stream)
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else:
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print(danger(sanitize(incorrect_byte)), end='', file=output_stream)
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print(sanitize(actual_line[actual_column+1:], max_line_length_shown=show_line_length - actual_column), file=output_stream)
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def print_line(line, description, line_color, output_stream):
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if line == b'\n':
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print("The", description, "line was an empty line (a '\\n').", file=output_stream)
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else:
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print("The", description, "line was:", file=output_stream)
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print(line_color(sanitize(line)), file=output_stream)
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def sanitize(line, max_line_length_shown=256):
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if len(line) > max_line_length_shown:
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line = line[0:max_line_length_shown] + b' ...'
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return repr(line.rstrip(b'\n'))[2:-1]
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def check_bad_characters(line, line_number, danger, expected):
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if re.search(rb'[\x00-\x08\x14-\x1f\x7f-\xff]', expected):
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return None
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m = re.search(rb'^(.*?)([\x00-\x08\x14-\x1f\x7f-\xff])', line)
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if not m:
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return None
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(prefix, offending_char) = m.groups()
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offending_value = ord(offending_char)
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if offending_value == 0:
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description = "zero byte ('" + danger('\\0') + "')"
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elif offending_value > 127:
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description = "non-ascii byte " + danger("\\x%02x" % (offending_value))
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else:
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description = "non-printable character " + danger("\\x%02x" % (offending_value))
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column = len(prefix)
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explanation = "a " + danger("non-ASCII byte") + " was printed.\n"
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explanation += "Byte %d of line %d of program output was a %s\n" % (column + 1, line_number, description)
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explanation += "Here is line %d with non-printable characters replaced with backslash-escaped equivalents:\n" % (line_number)
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line = repr(line)[2:-1] + '\n'
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line = re.sub(r'(\\x[0-9a-f][0-9a-f])', danger(r'\1'), line)
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explanation += line
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if offending_value == 255:
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explanation += "\nHave you accidentally printed the special EOF value getchar returns?\n"
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explanation += "For more information go to: " + explanation_url("eof_byte") + "\n"
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return explanation
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def getenv_boolean(name, default=False):
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if name in os.environ:
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value = os.environ[name]
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return value and value[0] not in "0fFnN"
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else:
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return default
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def getenv_int(name):
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try:
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return int(os.environ.get(name, 0))
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except ValueError:
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return 0
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EXPLANATION_BASE_URL = "https://comp1511unsw.github.io/dcc/"
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def explanation_url(page):
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return EXPLANATION_BASE_URL + page + ".html"

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