Add test for missing input encoding. Back to 100% coverage.

IPython/core/inputsplitter.py

@@ -1,419 +1,421 b''
 """Analysis of text input into executable blocks.
 
 The main class in this module, :class:`InputSplitter`, is designed to break
 input from either interactive, line-by-line environments or block-based ones,
 into standalone blocks that can be executed by Python as 'single' statements
 (thus triggering sys.displayhook).
 
 For more details, see the class docstring below.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 # stdlib
 import codeop
 import re
 import sys
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # FIXME: move these utilities to the general ward...
 
 # compiled regexps for autoindent management
 dedent_re = re.compile(r'^\s+raise|^\s+return|^\s+pass')
 ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)')
 
 
 def num_ini_spaces(s):
     """Return the number of initial spaces in a string.
 
     Note that tabs are counted as a single space.  For now, we do *not* support
     mixing of tabs and spaces in the user's input.
 
     Parameters
     ----------
     s : string
 
     Returns
     -------
     n : int
     """
 
     ini_spaces = ini_spaces_re.match(s)
     if ini_spaces:
         return ini_spaces.end()
     else:
         return 0
 
 
 def remove_comments(src):
     """Remove all comments from input source.
 
     Note: comments are NOT recognized inside of strings!
 
     Parameters
     ----------
     src : string
       A single or multiline input string.
 
     Returns
     -------
     String with all Python comments removed.
     """
 
     return re.sub('#.*', '', src)
 
 
 def get_input_encoding():
-    """Return the default standard input encoding."""
+    """Return the default standard input encoding.
+
+    If sys.stdin has no encoding, 'ascii' is returned."""
     # There are strange environments for which sys.stdin.encoding is None. We
     # ensure that a valid encoding is returned.
     encoding = getattr(sys.stdin, 'encoding', None)
     if encoding is None:
         encoding = 'ascii'
     return encoding
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 class InputSplitter(object):
     """An object that can split Python source input in executable blocks.
 
     This object is designed to be used in one of two basic modes:
 
     1. By feeding it python source line-by-line, using :meth:`push`.  In this
        mode, it will return on each push whether the currently pushed code
        could be executed already.  In addition, it provides a method called
        :meth:`push_accepts_more` that can be used to query whether more input
        can be pushed into a single interactive block.
 
     2. By calling :meth:`split_blocks` with a single, multiline Python string,
        that is then split into blocks each of which can be executed
        interactively as a single statement.
 
     This is a simple example of how an interactive terminal-based client can use
     this tool::
 
         isp = InputSplitter()
         while isp.push_accepts_more():
             indent = ' '*isp.indent_spaces
             prompt = '>>> ' + indent
             line = indent + raw_input(prompt)
             isp.push(line)
         print 'Input source was:\n', isp.source_reset(),
     """
     # Number of spaces of indentation computed from input that has been pushed
     # so far.  This is the attributes callers should query to get the current
     # indentation level, in order to provide auto-indent facilities.
     indent_spaces = 0
     # String, indicating the default input encoding.  It is computed by default
     # at initialization time via get_input_encoding(), but it can be reset by a
     # client with specific knowledge of the encoding.
     encoding = ''
     # String where the current full source input is stored, properly encoded.
     # Reading this attribute is the normal way of querying the currently pushed
     # source code, that has been properly encoded.
     source = ''
     # Code object corresponding to the current source.  It is automatically
     # synced to the source, so it can be queried at any time to obtain the code
     # object; it will be None if the source doesn't compile to valid Python.
     code = None
     # Input mode
     input_mode = 'append'
     
     # Private attributes
     
     # List with lines of input accumulated so far
     _buffer = None
     # Command compiler
     _compile = None
     # Mark when input has changed indentation all the way back to flush-left
     _full_dedent = False
     # Boolean indicating whether the current block is complete
     _is_complete = None
     
     def __init__(self, input_mode=None):
         """Create a new InputSplitter instance.
 
         Parameters
         ----------
         input_mode : str
 
           One of 'append', 'replace', default is 'append'.  This controls how
           new inputs are used: in 'append' mode, they are appended to the
           existing buffer and the whole buffer is compiled; in 'replace' mode,
           each new input completely replaces all prior inputs.  Replace mode is
           thus equivalent to prepending a full reset() to every push() call.
 
           In practice, line-oriented clients likely want to use 'append' mode
           while block-oriented ones will want to use 'replace'.
         """
         self._buffer = []
         self._compile = codeop.CommandCompiler()
         self.encoding = get_input_encoding()
         self.input_mode = InputSplitter.input_mode if input_mode is None \
                           else input_mode
 
     def reset(self):
         """Reset the input buffer and associated state."""
         self.indent_spaces = 0
         self._buffer[:] = []
         self.source = ''
         self.code = None
         self._is_complete = False
         self._full_dedent = False
 
     def source_reset(self):
         """Return the input source and perform a full reset.
         """
         out = self.source
         self.reset()
         return out
 
     def push(self, lines):
         """Push one ore more lines of input.
 
         This stores the given lines and returns a status code indicating
         whether the code forms a complete Python block or not.
 
         Any exceptions generated in compilation are swallowed, but if an
         exception was produced, the method returns True.
 
         Parameters
         ----------
         lines : string
           One or more lines of Python input.
         
         Returns
         -------
         is_complete : boolean
           True if the current input source (the result of the current input
         plus prior inputs) forms a complete Python execution block.  Note that
         this value is also stored as a private attribute (_is_complete), so it
         can be queried at any time.
         """
         if self.input_mode == 'replace':
             self.reset()
         
         # If the source code has leading blanks, add 'if 1:\n' to it
         # this allows execution of indented pasted code. It is tempting
         # to add '\n' at the end of source to run commands like ' a=1'
         # directly, but this fails for more complicated scenarios
         if not self._buffer and lines[:1] in [' ', '\t']:
             lines = 'if 1:\n%s' % lines
         
         self._store(lines)
         source = self.source
 
         # Before calling _compile(), reset the code object to None so that if an
         # exception is raised in compilation, we don't mislead by having
         # inconsistent code/source attributes.
         self.code, self._is_complete = None, None
 
         self._update_indent(lines)
         try:
             self.code = self._compile(source)
         # Invalid syntax can produce any of a number of different errors from
         # inside the compiler, so we have to catch them all.  Syntax errors
         # immediately produce a 'ready' block, so the invalid Python can be
         # sent to the kernel for evaluation with possible ipython
         # special-syntax conversion.
         except (SyntaxError, OverflowError, ValueError, TypeError,
                 MemoryError):
             self._is_complete = True
         else:
             # Compilation didn't produce any exceptions (though it may not have
             # given a complete code object)
             self._is_complete = self.code is not None
 
         return self._is_complete
 
     def push_accepts_more(self):
         """Return whether a block of interactive input can accept more input.
 
         This method is meant to be used by line-oriented frontends, who need to
         guess whether a block is complete or not based solely on prior and
         current input lines.  The InputSplitter considers it has a complete
         interactive block and will not accept more input only when either a
         SyntaxError is raised, or *all* of the following are true:
 
         1. The input compiles to a complete statement.
         
         2. The indentation level is flush-left (because if we are indented,
            like inside a function definition or for loop, we need to keep
            reading new input).
           
         3. There is one extra line consisting only of whitespace.
 
         Because of condition #3, this method should be used only by
         *line-oriented* frontends, since it means that intermediate blank lines
         are not allowed in function definitions (or any other indented block).
 
         Block-oriented frontends that have a separate keyboard event to
         indicate execution should use the :meth:`split_blocks` method instead.
 
         If the current input produces a syntax error, this method immediately
         returns False but does *not* raise the syntax error exception, as
         typically clients will want to send invalid syntax to an execution
         backend which might convert the invalid syntax into valid Python via
         one of the dynamic IPython mechanisms.
         """
             
         if not self._is_complete:
             return True
 
         if self.indent_spaces==0:
             return False
         
         last_line = self.source.splitlines()[-1]
         return bool(last_line and not last_line.isspace())
         
     def split_blocks(self, lines):
         """Split a multiline string into multiple input blocks.
 
         Note: this method starts by performing a full reset().
         
         Parameters
         ----------
         lines : str
           A possibly multiline string.
 
         Returns
         -------
         blocks : list
           A list of strings, each possibly multiline.  Each string corresponds
           to a single block that can be compiled in 'single' mode (unless it
           has a syntax error)."""
 
         # This code is fairly delicate.  If you make any changes here, make
         # absolutely sure that you do run the full test suite and ALL tests
         # pass.
 
         self.reset()
         blocks = []
         
         # Reversed copy so we can use pop() efficiently and consume the input
         # as a stack
         lines = lines.splitlines()[::-1]
         # Outer loop over all input
         while lines:
             # Inner loop to build each block
             while True:
                 # Safety exit from inner loop
                 if not lines:
                     break
                 # Grab next line but don't push it yet
                 next_line = lines.pop()
                 # Blank/empty lines are pushed as-is
                 if not next_line or next_line.isspace():
                     self.push(next_line)
                     continue
 
                 # Check indentation changes caused by the *next* line
                 indent_spaces, _full_dedent = self._find_indent(next_line)
 
                 # If the next line causes a dedent, it can be for two differnt
                 # reasons: either an explicit de-dent by the user or a
                 # return/raise/pass statement.  These MUST be handled
                 # separately:
                 #
                 # 1. the first case is only detected when the actual explicit
                 # dedent happens, and that would be the *first* line of a *new*
                 # block.  Thus, we must put the line back into the input buffer
                 # so that it starts a new block on the next pass.
                 #
                 # 2. the second case is detected in the line before the actual
                 # dedent happens, so , we consume the line and we can break out
                 # to start a new block.
 
                 # Case 1, explicit dedent causes a break
                 if _full_dedent and not next_line.startswith(' '):
                     lines.append(next_line)
                     break
                 
                 # Otherwise any line is pushed
                 self.push(next_line)
 
                 # Case 2, full dedent with full block ready:
                 if _full_dedent or \
                        self.indent_spaces==0 and not self.push_accepts_more():
                     break
             # Form the new block with the current source input
             blocks.append(self.source_reset())
             
         return blocks
 
     #------------------------------------------------------------------------
     # Private interface
     #------------------------------------------------------------------------
 
     def _find_indent(self, line):
         """Compute the new indentation level for a single line.
 
         Parameters
         ----------
         line : str
           A single new line of non-whitespace, non-comment Python input.
           
         Returns
         -------
         indent_spaces : int
           New value for the indent level (it may be equal to self.indent_spaces
         if indentation doesn't change.
 
         full_dedent : boolean
           Whether the new line causes a full flush-left dedent.
         """
         indent_spaces = self.indent_spaces
         full_dedent = self._full_dedent
         
         inisp = num_ini_spaces(line)
         if inisp < indent_spaces:
             indent_spaces = inisp
             if indent_spaces <= 0:
                 #print 'Full dedent in text',self.source # dbg
                 full_dedent = True
 
         if line[-1] == ':':
             indent_spaces += 4
         elif dedent_re.match(line):
             indent_spaces -= 4
             if indent_spaces <= 0:
                 full_dedent = True
 
         # Safety
         if indent_spaces < 0:
             indent_spaces = 0
             #print 'safety' # dbg
             
         return indent_spaces, full_dedent
         
     def _update_indent(self, lines):
         for line in remove_comments(lines).splitlines():
             if line and not line.isspace():
                 self.indent_spaces, self._full_dedent = self._find_indent(line)
 
     def _store(self, lines):
         """Store one or more lines of input.
 
         If input lines are not newline-terminated, a newline is automatically
         appended."""
 
         if lines.endswith('\n'):
             self._buffer.append(lines)
         else:
             self._buffer.append(lines+'\n')
         self._set_source()
 
     def _set_source(self):
         self.source = ''.join(self._buffer).encode(self.encoding)

IPython/core/tests/test_inputsplitter.py

@@ -1,346 +1,364 b''
 """Tests for the inputsplitter module.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 # stdlib
 import unittest
+import sys
 
 # Third party
 import nose.tools as nt
 
 # Our own
 from IPython.core import inputsplitter as isp
 
 #-----------------------------------------------------------------------------
 # Semi-complete examples (also used as tests)
 #-----------------------------------------------------------------------------
 def mini_interactive_loop(raw_input):
     """Minimal example of the logic of an interactive interpreter loop.
 
     This serves as an example, and it is used by the test system with a fake
     raw_input that simulates interactive input."""
 
     from IPython.core.inputsplitter import InputSplitter
     
     isp = InputSplitter()
     # In practice, this input loop would be wrapped in an outside loop to read
     # input indefinitely, until some exit/quit command was issued.  Here we
     # only illustrate the basic inner loop.
     while isp.push_accepts_more():
         indent = ' '*isp.indent_spaces
         prompt = '>>> ' + indent
         line = indent + raw_input(prompt)
         isp.push(line)
 
     # Here we just return input so we can use it in a test suite, but a real
     # interpreter would instead send it for execution somewhere.
     src = isp.source_reset()
     print 'Input source was:\n', src
     return src
 
 #-----------------------------------------------------------------------------
 # Test utilities, just for local use
 #-----------------------------------------------------------------------------
 
 def assemble(block):
     """Assemble a block into multi-line sub-blocks."""
     return ['\n'.join(sub_block)+'\n' for sub_block in block]
 
 
 def pseudo_input(lines):
     """Return a function that acts like raw_input but feeds the input list."""
     ilines = iter(lines)
     def raw_in(prompt):
         try:
             return next(ilines)
         except StopIteration:
             return ''
     return raw_in
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 def test_spaces():
     tests = [('', 0),
              (' ', 1),
              ('\n', 0),
              (' \n', 1),
              ('x', 0),
              (' x', 1),
              ('  x',2),
              ('    x',4),
              # Note: tabs are counted as a single whitespace!
              ('\tx', 1),
              ('\t x', 2),
              ]
     
     for s, nsp in tests:
         nt.assert_equal(isp.num_ini_spaces(s), nsp)
 
 
 def test_remove_comments():
     tests = [('text', 'text'),
              ('text # comment', 'text '),
              ('text # comment\n', 'text \n'),
              ('text # comment \n', 'text \n'),
              ('line # c \nline\n','line \nline\n'),
              ('line # c \nline#c2  \nline\nline #c\n\n',
               'line \nline\nline\nline \n\n'),
              ]
 
     for inp, out in tests:
         nt.assert_equal(isp.remove_comments(inp), out)
 
 
 def test_get_input_encoding():
     encoding = isp.get_input_encoding()
     nt.assert_true(isinstance(encoding, basestring))
     # simple-minded check that at least encoding a simple string works with the
     # encoding we got.
     nt.assert_equal('test'.encode(encoding), 'test')
 
 
+class NoInputEncodingTestCase(unittest.TestCase):
+    def setUp(self):
+        self.old_stdin = sys.stdin
+        class X: pass
+        fake_stdin = X()
+        sys.stdin = fake_stdin
+        
+    def test(self):
+        # Verify that if sys.stdin has no 'encoding' attribute we do the right
+        # thing
+        enc = isp.get_input_encoding()
+        self.assertEqual(enc, 'ascii')
+        
+    def tearDown(self):
+        sys.stdin = self.old_stdin
+
+
 class InputSplitterTestCase(unittest.TestCase):
     def setUp(self):
         self.isp = isp.InputSplitter()
 
     def test_reset(self):
         isp = self.isp
         isp.push('x=1')
         isp.reset()
         self.assertEqual(isp._buffer, [])
         self.assertEqual(isp.indent_spaces, 0)
         self.assertEqual(isp.source, '')
         self.assertEqual(isp.code, None)
         self.assertEqual(isp._is_complete, False)
 
     def test_source(self):
         self.isp._store('1')
         self.isp._store('2')
         self.assertEqual(self.isp.source, '1\n2\n')
         self.assertTrue(len(self.isp._buffer)>0)
         self.assertEqual(self.isp.source_reset(), '1\n2\n')
         self.assertEqual(self.isp._buffer, [])
         self.assertEqual(self.isp.source, '')
         
     def test_indent(self):
         isp = self.isp # shorthand
         isp.push('x=1')
         self.assertEqual(isp.indent_spaces, 0)
         isp.push('if 1:\n    x=1')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('y=2\n')
         self.assertEqual(isp.indent_spaces, 0)
         isp.push('if 1:')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('    x=1')
         self.assertEqual(isp.indent_spaces, 4)
         # Blank lines shouldn't change the indent level
         isp.push(' '*2)
         self.assertEqual(isp.indent_spaces, 4)
 
     def test_indent2(self):
         isp = self.isp
         # When a multiline statement contains parens or multiline strings, we
         # shouldn't get confused.
         isp.push("if 1:")
         isp.push("    x = (1+\n    2)")
         self.assertEqual(isp.indent_spaces, 4)
 
     def test_dedent(self):
         isp = self.isp # shorthand
         isp.push('if 1:')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('    pass')
         self.assertEqual(isp.indent_spaces, 0)
         
     def test_push(self):
         isp = self.isp
         self.assertTrue(isp.push('x=1'))
 
     def test_push2(self):
         isp = self.isp
         self.assertFalse(isp.push('if 1:'))
         for line in ['  x=1', '# a comment', '  y=2']:
             self.assertTrue(isp.push(line))
             
     def test_push3(self):
         """Test input with leading whitespace"""
         isp = self.isp
         isp.push('  x=1')
         isp.push('  y=2')
         self.assertEqual(isp.source, 'if 1:\n  x=1\n  y=2\n')
 
     def test_replace_mode(self):
         isp = self.isp
         isp.input_mode = 'replace'
         isp.push('x=1')
         self.assertEqual(isp.source, 'x=1\n')
         isp.push('x=2')
         self.assertEqual(isp.source, 'x=2\n')
 
     def test_push_accepts_more(self):
         isp = self.isp
         isp.push('x=1')
         self.assertFalse(isp.push_accepts_more())
 
     def test_push_accepts_more2(self):
         isp = self.isp
         isp.push('if 1:')
         self.assertTrue(isp.push_accepts_more())
         isp.push('  x=1')
         self.assertTrue(isp.push_accepts_more())
         isp.push('')
         self.assertFalse(isp.push_accepts_more())
         
     def test_push_accepts_more3(self):
         isp = self.isp
         isp.push("x = (2+\n3)")
         self.assertFalse(isp.push_accepts_more())
 
     def test_push_accepts_more4(self):
         isp = self.isp
         # When a multiline statement contains parens or multiline strings, we
         # shouldn't get confused.
         # FIXME: we should be able to better handle de-dents in statements like
         # multiline strings and multiline expressions (continued with \ or
         # parens).  Right now we aren't handling the indentation tracking quite
         # correctly with this, though in practice it may not be too much of a
         # problem.  We'll need to see.
         isp.push("if 1:")
         isp.push("    x = (2+")
         isp.push("    3)")
         self.assertTrue(isp.push_accepts_more())
         isp.push("    y = 3")
         self.assertTrue(isp.push_accepts_more())
         isp.push('')
         self.assertFalse(isp.push_accepts_more())
 
     def test_syntax_error(self):
         isp = self.isp
         # Syntax errors immediately produce a 'ready' block, so the invalid
         # Python can be sent to the kernel for evaluation with possible ipython
         # special-syntax conversion.
         isp.push('run foo')
         self.assertFalse(isp.push_accepts_more())
 
     def check_split(self, block_lines, compile=True):
         blocks = assemble(block_lines)
         lines = ''.join(blocks)
         oblock = self.isp.split_blocks(lines)
         self.assertEqual(oblock, blocks)
         if compile:
             for block in blocks:
                 self.isp._compile(block)
 
     def test_split(self):
         # All blocks of input we want to test in a list.  The format for each
         # block is a list of lists, with each inner lists consisting of all the
         # lines (as single-lines) that should make up a sub-block.
 
         # Note: do NOT put here sub-blocks that don't compile, as the
         # check_split() routine makes a final verification pass to check that
         # each sub_block, as returned by split_blocks(), does compile
         # correctly.
         all_blocks = [ [['x=1']],
 
                        [['x=1'],
                         ['y=2']],
 
                        [['x=1'],
                         ['# a comment'],
                         ['y=11']],
 
                        [['if 1:',
                          '  x=1'],
                         ['y=3']],
 
                        [['def f(x):',
                          '  return x'],
                         ['x=1']],
 
                        [['def f(x):',
                          '  x+=1',
                          '  ',
                          '  return x'],
                         ['x=1']],
 
                        [['def f(x):',
                          '  if x>0:',
                          '    y=1',
                          '  # a comment',
                          '  else:',
                          '    y=4',
                          ' ',
                          '  return y'],
                         ['x=1'],
                         ['if 1:',
                          '  y=11'] ],
                        
                        [['for i in range(10):'
                          '  x=i**2']],
 
                        [['for i in range(10):'
                          '  x=i**2'],
                         ['z = 1']],
                        ]
         for block_lines in all_blocks:
             self.check_split(block_lines)
         
     def test_split_syntax_errors(self):
         # Block splitting with invalid syntax
         all_blocks = [ [['a syntax error']],
             
                        [['x=1'],
                         ['a syntax error']],
 
                        [['for i in range(10):'
                          '  an error']],
                        
                        ]
         for block_lines in all_blocks:
             self.check_split(block_lines, compile=False)
 
 
 class InteractiveLoopTestCase(unittest.TestCase):
     """Tests for an interactive loop like a python shell.
     """
     def check_ns(self, lines, ns):
         """Validate that the given input lines produce the resulting namespace.
 
         Note: the input lines are given exactly as they would be typed in an
         auto-indenting environment, as mini_interactive_loop above already does
         auto-indenting and prepends spaces to the input.
         """
         src = mini_interactive_loop(pseudo_input(lines))
         test_ns = {}
         exec src in test_ns
         # We can't check that the provided ns is identical to the test_ns,
         # because Python fills test_ns with extra keys (copyright, etc).  But
         # we can check that the given dict is *contained* in test_ns
         for k,v in ns.items():
             self.assertEqual(test_ns[k], v)
         
     def test_simple(self):
         self.check_ns(['x=1'], dict(x=1))
 
     def test_simple2(self):
         self.check_ns(['if 1:', 'x=2'], dict(x=2))
 
     def test_xy(self):
         self.check_ns(['x=1; y=2'], dict(x=1, y=2))
 
     def test_abc(self):
         self.check_ns(['if 1:','a=1','b=2','c=3'], dict(a=1, b=2, c=3))
     
     def test_multi(self):
         self.check_ns(['x =(1+','1+','2)'], dict(x=4))