When two coding cookies are present, use the first. Fixes #1281.

Author: Guido van Rossum

mypy/test/data/parse-errors.test

@@ -453,12 +453,34 @@ file:2: error: Unknown encoding 'uft-8'
 [out]
 file:1: error: Unknown encoding 'Uft.8'
 
-[case testInvalidEncoding2]
+[case testInvalidEncoding3]
 #!/usr/bin python
 # vim: set fileencoding=uft8 :
 [out]
 file:2: error: Unknown encoding 'uft8'
 
+[case testDoubleEncoding]
+# coding: uft8
+# coding: utf8
+# The first coding cookie should be used and fail.
+[out]
+file:1: error: Unknown encoding 'uft8'
+
+[case testDoubleEncoding2]
+# Again the first cookie should be used and fail.
+# coding: uft8
+# coding: utf8
+[out]
+file:2: error: Unknown encoding 'uft8'
+
+[case testDoubleEncoding3]
+# If the third line were interpreted as a coding cookie, we'd get a
+# different error message.
+# coding: ascii
+á = 1
+[out]
+file:4: error: Unrecognized character
+
 [case testLongLiteralInPython3]
 2L
 0x2L

mypy/util.py

@@ -7,7 +7,7 @@
 
 T = TypeVar('T')
 
-ENCODING_RE = re.compile(br'(\s*#.*(\r\n?|\n))?\s*#.*coding[:=]\s*([-\w.]+)')
+ENCODING_RE = re.compile(br'(\s*#.*(\r\n?|\n)){0,1}?\s*#.*coding[:=]\s*([-\w.]+)')
 
 default_python2_interpreter = ['python2', 'python', '/usr/bin/python']