prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  sys.stdin not None and missing encoding attribute when running with pythonw.exe
  ## Environment data
  
  - PTVSD version: 4.2
  - OS and version: windows 10
  - Python version (& distribution if applicable, e.g. Anaconda): CPython 3.7 using **pythonw.exe**
  - Using VS Code or Visual Studio: VS
  
  ## Actual behavior
  
  None has no attribute encoding exception
  
  ## Expected  behavior
  
  Either sys.stdin.encoding works, or sys.stdin is None (it is None when running without debugging)
  
  
  ## Steps to reproduce:
  1. Debug this code using pythonw.exe (no console)
  ```
  import sys
  
  with open('issue4866.txt', 'wt') as f:
      f.write('hello\n')
      f.write(str(type(sys.stdin)) + '\n')
      if sys.stdin is not None:
          f.write(str(sys.stdin.encoding) + '\n')
      f.write('bye\n')
  ```
  
  From https://github.com/Microsoft/PTVS/issues/4866
  
  </issue>
  <code>
  [start of src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py]
  1 from _pydevd_bundle import pydevd_constants
  2 
  3 IS_PY3K = pydevd_constants.IS_PY3K
  4 
  5 class IORedirector:
  6     '''
  7     This class works to wrap a stream (stdout/stderr) with an additional redirect.
  8     '''
  9 
  10     def __init__(self, original, new_redirect, wrap_buffer=False):
  11         '''
  12         :param stream original:
  13             The stream to be wrapped (usually stdout/stderr).
  14 
  15         :param stream new_redirect:
  16             Usually IOBuf (below).
  17 
  18         :param bool wrap_buffer:
  19             Whether to create a buffer attribute (needed to mimick python 3 s
  20             tdout/stderr which has a buffer to write binary data).
  21         '''
  22         self._redirect_to = (original, new_redirect)
  23         if wrap_buffer and hasattr(original, 'buffer'):
  24             self.buffer = IORedirector(original.buffer, new_redirect.buffer, False)
  25 
  26     def write(self, s):
  27         # Note that writing to the original stream may fail for some reasons
  28         # (such as trying to write something that's not a string or having it closed).
  29         for r in self._redirect_to:
  30             r.write(s)
  31 
  32     def isatty(self):
  33         return self._redirect_to[0].isatty()
  34 
  35     def flush(self):
  36         for r in self._redirect_to:
  37             r.flush()
  38 
  39     def __getattr__(self, name):
  40         for r in self._redirect_to:
  41             if hasattr(r, name):
  42                 return getattr(r, name)
  43         raise AttributeError(name)
  44 
  45 class IOBuf:
  46     '''This class works as a replacement for stdio and stderr.
  47     It is a buffer and when its contents are requested, it will erase what
  48     it has so far so that the next return will not return the same contents again.
  49     '''
  50     def __init__(self):
  51         self.buflist = []
  52         import os
  53         self.encoding = os.environ.get('PYTHONIOENCODING', 'utf-8')
  54 
  55     def getvalue(self):
  56         b = self.buflist
  57         self.buflist = []  # clear it
  58         return ''.join(b)  # bytes on py2, str on py3.
  59     
  60     def write(self, s):
  61         if not IS_PY3K:
  62             if isinstance(s, unicode):
  63                 # can't use 'errors' as kwargs in py 2.6
  64                 s = s.encode(self.encoding, 'replace')
  65         else:
  66             if isinstance(s, bytes):
  67                 s = s.decode(self.encoding, errors='replace')
  68         self.buflist.append(s)
  69 
  70     def isatty(self):
  71         return False
  72 
  73     def flush(self):
  74         pass
  75 
  76     def empty(self):
  77         return len(self.buflist) == 0
  78 
  79 class _RedirectionsHolder:
  80     _stack_stdout = []
  81     _stack_stderr = []
  82 
  83 
  84 def start_redirect(keep_original_redirection=False, std='stdout'):
  85     '''
  86     @param std: 'stdout', 'stderr', or 'both'
  87     '''
  88     import sys
  89     buf = IOBuf()
  90 
  91     if std == 'both':
  92         config_stds = ['stdout', 'stderr']
  93     else:
  94         config_stds = [std]
  95 
  96     for std in config_stds:
  97         original = getattr(sys, std)
  98         stack = getattr(_RedirectionsHolder, '_stack_%s' % std)
  99         stack.append(original)
  100 
  101         if keep_original_redirection:
  102             setattr(sys, std, IORedirector(getattr(sys, std), buf))
  103         else:
  104             setattr(sys, std, buf)
  105     return buf
  106 
  107 
  108 def end_redirect(std='stdout'):
  109     import sys
  110     if std == 'both':
  111         config_stds = ['stdout', 'stderr']
  112     else:
  113         config_stds = [std]
  114     for std in config_stds:
  115         stack = getattr(_RedirectionsHolder, '_stack_%s' % std)
  116         setattr(sys, std, stack.pop())
  117 
  118
  [end of src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py b/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py
  --- a/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py
  +++ b/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py
  @@ -2,6 +2,7 @@
   
   IS_PY3K = pydevd_constants.IS_PY3K
   
  +
   class IORedirector:
       '''
       This class works to wrap a stream (stdout/stderr) with an additional redirect.
  @@ -10,7 +11,7 @@
       def __init__(self, original, new_redirect, wrap_buffer=False):
           '''
           :param stream original:
  -            The stream to be wrapped (usually stdout/stderr).
  +            The stream to be wrapped (usually stdout/stderr, but could be None).
   
           :param stream new_redirect:
               Usually IOBuf (below).
  @@ -27,14 +28,19 @@
           # Note that writing to the original stream may fail for some reasons
           # (such as trying to write something that's not a string or having it closed).
           for r in self._redirect_to:
  -            r.write(s)
  +            if hasattr(r, 'write'):
  +                r.write(s)
   
       def isatty(self):
  -        return self._redirect_to[0].isatty()
  +        for r in self._redirect_to:
  +            if hasattr(r, 'isatty'):
  +                return r.isatty()
  +        return False
   
       def flush(self):
           for r in self._redirect_to:
  -            r.flush()
  +            if hasattr(r, 'flush'):
  +                r.flush()
   
       def __getattr__(self, name):
           for r in self._redirect_to:
  @@ -42,11 +48,13 @@
                   return getattr(r, name)
           raise AttributeError(name)
   
  +
   class IOBuf:
       '''This class works as a replacement for stdio and stderr.
       It is a buffer and when its contents are requested, it will erase what
       it has so far so that the next return will not return the same contents again.
       '''
  +
       def __init__(self):
           self.buflist = []
           import os
  @@ -56,7 +64,7 @@
           b = self.buflist
           self.buflist = []  # clear it
           return ''.join(b)  # bytes on py2, str on py3.
  -    
  +
       def write(self, s):
           if not IS_PY3K:
               if isinstance(s, unicode):
  @@ -76,6 +84,7 @@
       def empty(self):
           return len(self.buflist) == 0
   
  +
   class _RedirectionsHolder:
       _stack_stdout = []
       _stack_stderr = []
  
verification_info: {"golden_diff": "diff --git a/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py b/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py\n--- a/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py\n+++ b/src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py\n@@ -2,6 +2,7 @@\n \n IS_PY3K = pydevd_constants.IS_PY3K\n \n+\n class IORedirector:\n     '''\n     This class works to wrap a stream (stdout/stderr) with an additional redirect.\n@@ -10,7 +11,7 @@\n     def __init__(self, original, new_redirect, wrap_buffer=False):\n         '''\n         :param stream original:\n-            The stream to be wrapped (usually stdout/stderr).\n+            The stream to be wrapped (usually stdout/stderr, but could be None).\n \n         :param stream new_redirect:\n             Usually IOBuf (below).\n@@ -27,14 +28,19 @@\n         # Note that writing to the original stream may fail for some reasons\n         # (such as trying to write something that's not a string or having it closed).\n         for r in self._redirect_to:\n-            r.write(s)\n+            if hasattr(r, 'write'):\n+                r.write(s)\n \n     def isatty(self):\n-        return self._redirect_to[0].isatty()\n+        for r in self._redirect_to:\n+            if hasattr(r, 'isatty'):\n+                return r.isatty()\n+        return False\n \n     def flush(self):\n         for r in self._redirect_to:\n-            r.flush()\n+            if hasattr(r, 'flush'):\n+                r.flush()\n \n     def __getattr__(self, name):\n         for r in self._redirect_to:\n@@ -42,11 +48,13 @@\n                 return getattr(r, name)\n         raise AttributeError(name)\n \n+\n class IOBuf:\n     '''This class works as a replacement for stdio and stderr.\n     It is a buffer and when its contents are requested, it will erase what\n     it has so far so that the next return will not return the same contents again.\n     '''\n+\n     def __init__(self):\n         self.buflist = []\n         import os\n@@ -56,7 +64,7 @@\n         b = self.buflist\n         self.buflist = []  # clear it\n         return ''.join(b)  # bytes on py2, str on py3.\n-    \n+\n     def write(self, s):\n         if not IS_PY3K:\n             if isinstance(s, unicode):\n@@ -76,6 +84,7 @@\n     def empty(self):\n         return len(self.buflist) == 0\n \n+\n class _RedirectionsHolder:\n     _stack_stdout = []\n     _stack_stderr = []\n", "issue": "sys.stdin not None and missing encoding attribute when running with pythonw.exe\n## Environment data\r\n\r\n- PTVSD version: 4.2\r\n- OS and version: windows 10\r\n- Python version (& distribution if applicable, e.g. Anaconda): CPython 3.7 using **pythonw.exe**\r\n- Using VS Code or Visual Studio: VS\r\n\r\n## Actual behavior\r\n\r\nNone has no attribute encoding exception\r\n\r\n## Expected  behavior\r\n\r\nEither sys.stdin.encoding works, or sys.stdin is None (it is None when running without debugging)\r\n\r\n\r\n## Steps to reproduce:\r\n1. Debug this code using pythonw.exe (no console)\r\n```\r\nimport sys\r\n\r\nwith open('issue4866.txt', 'wt') as f:\r\n    f.write('hello\\n')\r\n    f.write(str(type(sys.stdin)) + '\\n')\r\n    if sys.stdin is not None:\r\n        f.write(str(sys.stdin.encoding) + '\\n')\r\n    f.write('bye\\n')\r\n```\r\n\r\nFrom https://github.com/Microsoft/PTVS/issues/4866\n", "before_files": [{"content": "from _pydevd_bundle import pydevd_constants\n\nIS_PY3K = pydevd_constants.IS_PY3K\n\nclass IORedirector:\n    '''\n    This class works to wrap a stream (stdout/stderr) with an additional redirect.\n    '''\n\n    def __init__(self, original, new_redirect, wrap_buffer=False):\n        '''\n        :param stream original:\n            The stream to be wrapped (usually stdout/stderr).\n\n        :param stream new_redirect:\n            Usually IOBuf (below).\n\n        :param bool wrap_buffer:\n            Whether to create a buffer attribute (needed to mimick python 3 s\n            tdout/stderr which has a buffer to write binary data).\n        '''\n        self._redirect_to = (original, new_redirect)\n        if wrap_buffer and hasattr(original, 'buffer'):\n            self.buffer = IORedirector(original.buffer, new_redirect.buffer, False)\n\n    def write(self, s):\n        # Note that writing to the original stream may fail for some reasons\n        # (such as trying to write something that's not a string or having it closed).\n        for r in self._redirect_to:\n            r.write(s)\n\n    def isatty(self):\n        return self._redirect_to[0].isatty()\n\n    def flush(self):\n        for r in self._redirect_to:\n            r.flush()\n\n    def __getattr__(self, name):\n        for r in self._redirect_to:\n            if hasattr(r, name):\n                return getattr(r, name)\n        raise AttributeError(name)\n\nclass IOBuf:\n    '''This class works as a replacement for stdio and stderr.\n    It is a buffer and when its contents are requested, it will erase what\n    it has so far so that the next return will not return the same contents again.\n    '''\n    def __init__(self):\n        self.buflist = []\n        import os\n        self.encoding = os.environ.get('PYTHONIOENCODING', 'utf-8')\n\n    def getvalue(self):\n        b = self.buflist\n        self.buflist = []  # clear it\n        return ''.join(b)  # bytes on py2, str on py3.\n    \n    def write(self, s):\n        if not IS_PY3K:\n            if isinstance(s, unicode):\n                # can't use 'errors' as kwargs in py 2.6\n                s = s.encode(self.encoding, 'replace')\n        else:\n            if isinstance(s, bytes):\n                s = s.decode(self.encoding, errors='replace')\n        self.buflist.append(s)\n\n    def isatty(self):\n        return False\n\n    def flush(self):\n        pass\n\n    def empty(self):\n        return len(self.buflist) == 0\n\nclass _RedirectionsHolder:\n    _stack_stdout = []\n    _stack_stderr = []\n\n\ndef start_redirect(keep_original_redirection=False, std='stdout'):\n    '''\n    @param std: 'stdout', 'stderr', or 'both'\n    '''\n    import sys\n    buf = IOBuf()\n\n    if std == 'both':\n        config_stds = ['stdout', 'stderr']\n    else:\n        config_stds = [std]\n\n    for std in config_stds:\n        original = getattr(sys, std)\n        stack = getattr(_RedirectionsHolder, '_stack_%s' % std)\n        stack.append(original)\n\n        if keep_original_redirection:\n            setattr(sys, std, IORedirector(getattr(sys, std), buf))\n        else:\n            setattr(sys, std, buf)\n    return buf\n\n\ndef end_redirect(std='stdout'):\n    import sys\n    if std == 'both':\n        config_stds = ['stdout', 'stderr']\n    else:\n        config_stds = [std]\n    for std in config_stds:\n        stack = getattr(_RedirectionsHolder, '_stack_%s' % std)\n        setattr(sys, std, stack.pop())\n\n", "path": "src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_io.py"}]}