1 | """Python part of the warnings subsystem."""
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2 |
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3 | # Note: function level imports should *not* be used
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4 | # in this module as it may cause import lock deadlock.
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5 | # See bug 683658.
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6 | import linecache
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7 | import sys
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8 | import types
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9 |
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10 | __all__ = ["warn", "warn_explicit", "showwarning",
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11 | "formatwarning", "filterwarnings", "simplefilter",
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12 | "resetwarnings", "catch_warnings"]
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13 |
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14 |
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15 | def warnpy3k(message, category=None, stacklevel=1):
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16 | """Issue a deprecation warning for Python 3.x related changes.
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17 |
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18 | Warnings are omitted unless Python is started with the -3 option.
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19 | """
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20 | if sys.py3kwarning:
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21 | if category is None:
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22 | category = DeprecationWarning
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23 | warn(message, category, stacklevel+1)
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24 |
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25 | def _show_warning(message, category, filename, lineno, file=None, line=None):
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26 | """Hook to write a warning to a file; replace if you like."""
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27 | if file is None:
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28 | file = sys.stderr
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29 | if file is None:
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30 | # sys.stderr is None - warnings get lost
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31 | return
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32 | try:
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33 | file.write(formatwarning(message, category, filename, lineno, line))
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34 | except (IOError, UnicodeError):
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35 | pass # the file (probably stderr) is invalid - this warning gets lost.
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36 | # Keep a working version around in case the deprecation of the old API is
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37 | # triggered.
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38 | showwarning = _show_warning
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39 |
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40 | def formatwarning(message, category, filename, lineno, line=None):
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41 | """Function to format a warning the standard way."""
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42 | try:
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43 | unicodetype = unicode
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44 | except NameError:
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45 | unicodetype = ()
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46 | try:
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47 | message = str(message)
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48 | except UnicodeEncodeError:
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49 | pass
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50 | s = "%s: %s: %s\n" % (lineno, category.__name__, message)
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51 | line = linecache.getline(filename, lineno) if line is None else line
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52 | if line:
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53 | line = line.strip()
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54 | if isinstance(s, unicodetype) and isinstance(line, str):
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55 | line = unicode(line, 'latin1')
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56 | s += " %s\n" % line
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57 | if isinstance(s, unicodetype) and isinstance(filename, str):
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58 | enc = sys.getfilesystemencoding()
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59 | if enc:
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60 | try:
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61 | filename = unicode(filename, enc)
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62 | except UnicodeDecodeError:
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63 | pass
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64 | s = "%s:%s" % (filename, s)
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65 | return s
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66 |
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67 | def filterwarnings(action, message="", category=Warning, module="", lineno=0,
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68 | append=0):
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69 | """Insert an entry into the list of warnings filters (at the front).
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70 |
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71 | 'action' -- one of "error", "ignore", "always", "default", "module",
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72 | or "once"
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73 | 'message' -- a regex that the warning message must match
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74 | 'category' -- a class that the warning must be a subclass of
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75 | 'module' -- a regex that the module name must match
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76 | 'lineno' -- an integer line number, 0 matches all warnings
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77 | 'append' -- if true, append to the list of filters
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78 | """
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79 | import re
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80 | assert action in ("error", "ignore", "always", "default", "module",
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81 | "once"), "invalid action: %r" % (action,)
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82 | assert isinstance(message, basestring), "message must be a string"
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83 | assert isinstance(category, (type, types.ClassType)), \
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84 | "category must be a class"
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85 | assert issubclass(category, Warning), "category must be a Warning subclass"
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86 | assert isinstance(module, basestring), "module must be a string"
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87 | assert isinstance(lineno, int) and lineno >= 0, \
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88 | "lineno must be an int >= 0"
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89 | item = (action, re.compile(message, re.I), category,
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90 | re.compile(module), lineno)
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91 | if append:
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92 | filters.append(item)
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93 | else:
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94 | filters.insert(0, item)
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95 |
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96 | def simplefilter(action, category=Warning, lineno=0, append=0):
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97 | """Insert a simple entry into the list of warnings filters (at the front).
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98 |
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99 | A simple filter matches all modules and messages.
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100 | 'action' -- one of "error", "ignore", "always", "default", "module",
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101 | or "once"
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102 | 'category' -- a class that the warning must be a subclass of
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103 | 'lineno' -- an integer line number, 0 matches all warnings
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104 | 'append' -- if true, append to the list of filters
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105 | """
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106 | assert action in ("error", "ignore", "always", "default", "module",
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107 | "once"), "invalid action: %r" % (action,)
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108 | assert isinstance(lineno, int) and lineno >= 0, \
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109 | "lineno must be an int >= 0"
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110 | item = (action, None, category, None, lineno)
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111 | if append:
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112 | filters.append(item)
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113 | else:
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114 | filters.insert(0, item)
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115 |
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116 | def resetwarnings():
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117 | """Clear the list of warning filters, so that no filters are active."""
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118 | filters[:] = []
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119 |
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120 | class _OptionError(Exception):
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121 | """Exception used by option processing helpers."""
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122 | pass
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123 |
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124 | # Helper to process -W options passed via sys.warnoptions
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125 | def _processoptions(args):
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126 | for arg in args:
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127 | try:
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128 | _setoption(arg)
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129 | except _OptionError, msg:
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130 | print >>sys.stderr, "Invalid -W option ignored:", msg
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131 |
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132 | # Helper for _processoptions()
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133 | def _setoption(arg):
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134 | import re
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135 | parts = arg.split(':')
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136 | if len(parts) > 5:
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137 | raise _OptionError("too many fields (max 5): %r" % (arg,))
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138 | while len(parts) < 5:
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139 | parts.append('')
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140 | action, message, category, module, lineno = [s.strip()
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141 | for s in parts]
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142 | action = _getaction(action)
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143 | message = re.escape(message)
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144 | category = _getcategory(category)
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145 | module = re.escape(module)
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146 | if module:
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147 | module = module + '$'
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148 | if lineno:
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149 | try:
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150 | lineno = int(lineno)
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151 | if lineno < 0:
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152 | raise ValueError
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153 | except (ValueError, OverflowError):
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154 | raise _OptionError("invalid lineno %r" % (lineno,))
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155 | else:
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156 | lineno = 0
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157 | filterwarnings(action, message, category, module, lineno)
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158 |
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159 | # Helper for _setoption()
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160 | def _getaction(action):
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161 | if not action:
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162 | return "default"
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163 | if action == "all": return "always" # Alias
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164 | for a in ('default', 'always', 'ignore', 'module', 'once', 'error'):
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165 | if a.startswith(action):
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166 | return a
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167 | raise _OptionError("invalid action: %r" % (action,))
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168 |
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169 | # Helper for _setoption()
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170 | def _getcategory(category):
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171 | import re
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172 | if not category:
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173 | return Warning
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174 | if re.match("^[a-zA-Z0-9_]+$", category):
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175 | try:
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176 | cat = eval(category)
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177 | except NameError:
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178 | raise _OptionError("unknown warning category: %r" % (category,))
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179 | else:
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180 | i = category.rfind(".")
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181 | module = category[:i]
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182 | klass = category[i+1:]
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183 | try:
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184 | m = __import__(module, None, None, [klass])
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185 | except ImportError:
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186 | raise _OptionError("invalid module name: %r" % (module,))
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187 | try:
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188 | cat = getattr(m, klass)
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189 | except AttributeError:
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190 | raise _OptionError("unknown warning category: %r" % (category,))
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191 | if not issubclass(cat, Warning):
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192 | raise _OptionError("invalid warning category: %r" % (category,))
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193 | return cat
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194 |
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195 |
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196 | # Code typically replaced by _warnings
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197 | def warn(message, category=None, stacklevel=1):
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198 | """Issue a warning, or maybe ignore it or raise an exception."""
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199 | # Check if message is already a Warning object
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200 | if isinstance(message, Warning):
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201 | category = message.__class__
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202 | # Check category argument
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203 | if category is None:
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204 | category = UserWarning
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205 | assert issubclass(category, Warning)
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206 | # Get context information
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207 | try:
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208 | caller = sys._getframe(stacklevel)
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209 | except ValueError:
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210 | globals = sys.__dict__
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211 | lineno = 1
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212 | else:
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213 | globals = caller.f_globals
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214 | lineno = caller.f_lineno
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215 | if '__name__' in globals:
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216 | module = globals['__name__']
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217 | else:
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218 | module = "<string>"
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219 | filename = globals.get('__file__')
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220 | if filename:
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221 | fnl = filename.lower()
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222 | if fnl.endswith((".pyc", ".pyo")):
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223 | filename = filename[:-1]
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224 | else:
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225 | if module == "__main__":
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226 | try:
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227 | filename = sys.argv[0]
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228 | except AttributeError:
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229 | # embedded interpreters don't have sys.argv, see bug #839151
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230 | filename = '__main__'
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231 | if not filename:
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232 | filename = module
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233 | registry = globals.setdefault("__warningregistry__", {})
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234 | warn_explicit(message, category, filename, lineno, module, registry,
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235 | globals)
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236 |
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237 | def warn_explicit(message, category, filename, lineno,
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238 | module=None, registry=None, module_globals=None):
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239 | lineno = int(lineno)
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240 | if module is None:
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241 | module = filename or "<unknown>"
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242 | if module[-3:].lower() == ".py":
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243 | module = module[:-3] # XXX What about leading pathname?
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244 | if registry is None:
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245 | registry = {}
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246 | if isinstance(message, Warning):
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247 | text = str(message)
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248 | category = message.__class__
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249 | else:
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250 | text = message
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251 | message = category(message)
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252 | key = (text, category, lineno)
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253 | # Quick test for common case
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254 | if registry.get(key):
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255 | return
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256 | # Search the filters
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257 | for item in filters:
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258 | action, msg, cat, mod, ln = item
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259 | if ((msg is None or msg.match(text)) and
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260 | issubclass(category, cat) and
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261 | (mod is None or mod.match(module)) and
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262 | (ln == 0 or lineno == ln)):
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263 | break
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264 | else:
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265 | action = defaultaction
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266 | # Early exit actions
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267 | if action == "ignore":
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268 | registry[key] = 1
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269 | return
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270 |
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271 | # Prime the linecache for formatting, in case the
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272 | # "file" is actually in a zipfile or something.
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273 | linecache.getlines(filename, module_globals)
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274 |
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275 | if action == "error":
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276 | raise message
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277 | # Other actions
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278 | if action == "once":
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279 | registry[key] = 1
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280 | oncekey = (text, category)
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281 | if onceregistry.get(oncekey):
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282 | return
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283 | onceregistry[oncekey] = 1
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284 | elif action == "always":
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285 | pass
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286 | elif action == "module":
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287 | registry[key] = 1
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288 | altkey = (text, category, 0)
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289 | if registry.get(altkey):
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290 | return
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291 | registry[altkey] = 1
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292 | elif action == "default":
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293 | registry[key] = 1
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294 | else:
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295 | # Unrecognized actions are errors
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296 | raise RuntimeError(
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297 | "Unrecognized action (%r) in warnings.filters:\n %s" %
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298 | (action, item))
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299 | # Print message and context
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300 | showwarning(message, category, filename, lineno)
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301 |
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302 |
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303 | class WarningMessage(object):
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304 |
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305 | """Holds the result of a single showwarning() call."""
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306 |
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307 | _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file",
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308 | "line")
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309 |
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310 | def __init__(self, message, category, filename, lineno, file=None,
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311 | line=None):
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312 | local_values = locals()
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313 | for attr in self._WARNING_DETAILS:
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314 | setattr(self, attr, local_values[attr])
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315 | self._category_name = category.__name__ if category else None
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316 |
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317 | def __str__(self):
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318 | return ("{message : %r, category : %r, filename : %r, lineno : %s, "
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319 | "line : %r}" % (self.message, self._category_name,
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320 | self.filename, self.lineno, self.line))
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321 |
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322 |
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323 | class catch_warnings(object):
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324 |
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325 | """A context manager that copies and restores the warnings filter upon
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326 | exiting the context.
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327 |
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328 | The 'record' argument specifies whether warnings should be captured by a
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329 | custom implementation of warnings.showwarning() and be appended to a list
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330 | returned by the context manager. Otherwise None is returned by the context
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331 | manager. The objects appended to the list are arguments whose attributes
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332 | mirror the arguments to showwarning().
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333 |
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334 | The 'module' argument is to specify an alternative module to the module
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335 | named 'warnings' and imported under that name. This argument is only useful
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336 | when testing the warnings module itself.
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337 |
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338 | """
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339 |
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340 | def __init__(self, record=False, module=None):
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341 | """Specify whether to record warnings and if an alternative module
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342 | should be used other than sys.modules['warnings'].
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343 |
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344 | For compatibility with Python 3.0, please consider all arguments to be
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345 | keyword-only.
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346 |
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347 | """
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348 | self._record = record
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349 | self._module = sys.modules['warnings'] if module is None else module
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350 | self._entered = False
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351 |
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352 | def __repr__(self):
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353 | args = []
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354 | if self._record:
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355 | args.append("record=True")
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356 | if self._module is not sys.modules['warnings']:
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357 | args.append("module=%r" % self._module)
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358 | name = type(self).__name__
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359 | return "%s(%s)" % (name, ", ".join(args))
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360 |
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361 | def __enter__(self):
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362 | if self._entered:
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363 | raise RuntimeError("Cannot enter %r twice" % self)
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364 | self._entered = True
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365 | self._filters = self._module.filters
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366 | self._module.filters = self._filters[:]
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367 | self._showwarning = self._module.showwarning
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368 | if self._record:
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369 | log = []
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370 | def showwarning(*args, **kwargs):
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371 | log.append(WarningMessage(*args, **kwargs))
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372 | self._module.showwarning = showwarning
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373 | return log
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374 | else:
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375 | return None
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376 |
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377 | def __exit__(self, *exc_info):
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378 | if not self._entered:
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379 | raise RuntimeError("Cannot exit %r without entering first" % self)
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380 | self._module.filters = self._filters
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381 | self._module.showwarning = self._showwarning
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382 |
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383 |
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384 | # filters contains a sequence of filter 5-tuples
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385 | # The components of the 5-tuple are:
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386 | # - an action: error, ignore, always, default, module, or once
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387 | # - a compiled regex that must match the warning message
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388 | # - a class representing the warning category
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389 | # - a compiled regex that must match the module that is being warned
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390 | # - a line number for the line being warning, or 0 to mean any line
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391 | # If either if the compiled regexs are None, match anything.
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392 | _warnings_defaults = False
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393 | try:
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394 | from _warnings import (filters, default_action, once_registry,
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395 | warn, warn_explicit)
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396 | defaultaction = default_action
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397 | onceregistry = once_registry
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398 | _warnings_defaults = True
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399 | except ImportError:
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400 | filters = []
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401 | defaultaction = "default"
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402 | onceregistry = {}
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403 |
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404 |
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405 | # Module initialization
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406 | _processoptions(sys.warnoptions)
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407 | if not _warnings_defaults:
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408 | silence = [ImportWarning, PendingDeprecationWarning]
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409 | # Don't silence DeprecationWarning if -3 or -Q was used.
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410 | if not sys.py3kwarning and not sys.flags.division_warning:
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411 | silence.append(DeprecationWarning)
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412 | for cls in silence:
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413 | simplefilter("ignore", category=cls)
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414 | bytes_warning = sys.flags.bytes_warning
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415 | if bytes_warning > 1:
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416 | bytes_action = "error"
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417 | elif bytes_warning:
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418 | bytes_action = "default"
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419 | else:
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420 | bytes_action = "ignore"
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421 | simplefilter(bytes_action, category=BytesWarning, append=1)
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422 | del _warnings_defaults
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