Patch #1537 from Chad Austin

Change GeneratorExit's base class from Exception to BaseException

7 files changed, 683 insertions, 6 deletions

diff --git a/Doc/library/exceptions.rst b/Doc/library/exceptions.rst
index d29ce12..3c404e4 100644
--- a/Doc/library/exceptions.rst
+++ b/Doc/library/exceptions.rst
@@ -135,6 +135,13 @@ The following exceptions are the exceptions that are actually raised.
 
 .. exception:: GeneratorExit
 
+     Raise when a :term:`generator`\'s :meth:`close` method is called.  It
+     directly inherits from :exc:`BaseException` instead of :exc:`Exception` since
+     it is technically not an error.
+
+    .. versionchanged:: 3.0 
+       Changed to inherit from :exc:`BaseException`.
+
    Raise when a :term:`generator`\'s :meth:`close` method is called.
 
 
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 64f620b..4bb0074 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -413,9 +413,6 @@ generator functions::
    ...         while True:
    ...             try:
    ...                 value = (yield value)
-   ...             except GeneratorExit:
-   ...                 # never catch GeneratorExit
-   ...                 raise
    ...             except Exception, e:
    ...                 value = e
    ...     finally:
diff --git a/Lib/distutils/msvc9compiler.py b/Lib/distutils/msvc9compiler.py
new file mode 100644
index 0000000..a6cff2c
--- /dev/null
+++ b/Lib/distutils/msvc9compiler.py
@@ -0,0 +1,658 @@
+"""distutils.msvc9compiler
+
+Contains MSVCCompiler, an implementation of the abstract CCompiler class
+for the Microsoft Visual Studio 2008.
+
+The module is compatible with VS 2005 and VS 2008. You can find legacy support
+for older versions of VS in distutils.msvccompiler.
+"""
+
+# Written by Perry Stoll
+# hacked by Robin Becker and Thomas Heller to do a better job of
+#   finding DevStudio (through the registry)
+# ported to VS2005 and VS 2008 by Christian Heimes
+
+__revision__ = "$Id$"
+
+import os
+import subprocess
+import sys
+from distutils.errors import (DistutilsExecError, DistutilsPlatformError,
+    CompileError, LibError, LinkError)
+from distutils.ccompiler import (CCompiler, gen_preprocess_options,
+    gen_lib_options)
+from distutils import log
+
+import _winreg
+
+RegOpenKeyEx = _winreg.OpenKeyEx
+RegEnumKey = _winreg.EnumKey
+RegEnumValue = _winreg.EnumValue
+RegError = _winreg.error
+
+HKEYS = (_winreg.HKEY_USERS,
+         _winreg.HKEY_CURRENT_USER,
+         _winreg.HKEY_LOCAL_MACHINE,
+         _winreg.HKEY_CLASSES_ROOT)
+
+VS_BASE = r"Software\Microsoft\VisualStudio\%0.1f"
+WINSDK_BASE = r"Software\Microsoft\Microsoft SDKs\Windows"
+NET_BASE = r"Software\Microsoft\.NETFramework"
+ARCHS = {'DEFAULT' : 'x86',
+    'intel' : 'x86', 'x86' : 'x86',
+    'amd64' : 'x64', 'x64' : 'x64',
+    'itanium' : 'ia64', 'ia64' : 'ia64',
+    }
+
+# The globals VERSION, ARCH, MACROS and VC_ENV are defined later
+
+class Reg:
+    """Helper class to read values from the registry
+    """
+
+    @classmethod
+    def get_value(cls, path, key):
+        for base in HKEYS:
+            d = cls.read_values(base, path)
+            if d and key in d:
+                return d[key]
+        raise KeyError(key)
+
+    @classmethod
+    def read_keys(cls, base, key):
+        """Return list of registry keys."""
+        try:
+            handle = RegOpenKeyEx(base, key)
+        except RegError:
+            return None
+        L = []
+        i = 0
+        while True:
+            try:
+                k = RegEnumKey(handle, i)
+            except RegError:
+                break
+            L.append(k)
+            i += 1
+        return L
+
+    @classmethod
+    def read_values(cls, base, key):
+        """Return dict of registry keys and values.
+
+        All names are converted to lowercase.
+        """
+        try:
+            handle = RegOpenKeyEx(base, key)
+        except RegError:
+            return None
+        d = {}
+        i = 0
+        while True:
+            try:
+                name, value, type = RegEnumValue(handle, i)
+            except RegError:
+                break
+            name = name.lower()
+            d[cls.convert_mbcs(name)] = cls.convert_mbcs(value)
+            i += 1
+        return d
+
+    @staticmethod
+    def convert_mbcs(s):
+        dec = getattr(s, "decode", None)
+        if dec is not None:
+            try:
+                s = dec("mbcs")
+            except UnicodeError:
+                pass
+        return s
+
+class MacroExpander:
+
+    def __init__(self, version):
+        self.macros = {}
+        self.vsbase = VS_BASE % version
+        self.load_macros(version)
+
+    def set_macro(self, macro, path, key):
+        self.macros["$(%s)" % macro] = Reg.get_value(path, key)
+
+    def load_macros(self, version):
+        self.set_macro("VCInstallDir", self.vsbase + r"\Setup\VC", "productdir")
+        self.set_macro("VSInstallDir", self.vsbase + r"\Setup\VS", "productdir")
+        self.set_macro("FrameworkDir", NET_BASE, "installroot")
+        try:
+            if version >= 8.0:
+                self.set_macro("FrameworkSDKDir", NET_BASE,
+                               "sdkinstallrootv2.0")
+            else:
+                raise KeyError("sdkinstallrootv2.0")
+        except KeyError as exc: #
+            raise DistutilsPlatformError(
+            """Python was built with Visual Studio 2008;
+extensions must be built with a compiler than can generate compatible binaries.
+Visual Studio 2008 was not found on this system. If you have Cygwin installed,
+you can try compiling with MingW32, by passing "-c mingw32" to setup.py.""")
+
+        if version >= 9.0:
+            self.set_macro("FrameworkVersion", self.vsbase, "clr version")
+            self.set_macro("WindowsSdkDir", WINSDK_BASE, "currentinstallfolder")
+        else:
+            p = r"Software\Microsoft\NET Framework Setup\Product"
+            for base in HKEYS:
+                try:
+                    h = RegOpenKeyEx(base, p)
+                except RegError:
+                    continue
+                key = RegEnumKey(h, 0)
+                d = Reg.get_value(base, r"%s\%s" % (p, key))
+                self.macros["$(FrameworkVersion)"] = d["version"]
+
+    def sub(self, s):
+        for k, v in self.macros.items():
+            s = s.replace(k, v)
+        return s
+
+def get_build_version():
+    """Return the version of MSVC that was used to build Python.
+
+    For Python 2.3 and up, the version number is included in
+    sys.version.  For earlier versions, assume the compiler is MSVC 6.
+    """
+    prefix = "MSC v."
+    i = sys.version.find(prefix)
+    if i == -1:
+        return 6
+    i = i + len(prefix)
+    s, rest = sys.version[i:].split(" ", 1)
+    majorVersion = int(s[:-2]) - 6
+    minorVersion = int(s[2:3]) / 10.0
+    # I don't think paths are affected by minor version in version 6
+    if majorVersion == 6:
+        minorVersion = 0
+    if majorVersion >= 6:
+        return majorVersion + minorVersion
+    # else we don't know what version of the compiler this is
+    return None
+
+def get_build_architecture():
+    """Return the processor architecture.
+
+    Possible results are "x86" or "amd64".
+    """
+    prefix = " bit ("
+    i = sys.version.find(prefix)
+    if i == -1:
+        return "x86"
+    j = sys.version.find(")", i)
+    sysarch = sys.version[i+len(prefix):j].lower()
+    arch = ARCHS.get(sysarch, None)
+    if arch is None:
+        return ARCHS['DEFAULT']
+    else:
+        return arch
+
+def normalize_and_reduce_paths(paths):
+    """Return a list of normalized paths with duplicates removed.
+
+    The current order of paths is maintained.
+    """
+    # Paths are normalized so things like:  /a and /a/ aren't both preserved.
+    reduced_paths = []
+    for p in paths:
+        np = os.path.normpath(p)
+        # XXX(nnorwitz): O(n**2), if reduced_paths gets long perhaps use a set.
+        if np not in reduced_paths:
+            reduced_paths.append(np)
+    return reduced_paths
+
+def find_vcvarsall(version):
+    """Find the vcvarsall.bat file
+
+    At first it tries to find the productdir of VS 2008 in the registry. If
+    that fails it falls back to the VS90COMNTOOLS env var.
+    """
+    vsbase = VS_BASE % version
+    try:
+        productdir = Reg.get_value(r"%s\Setup\VC" % vsbase,
+                                   "productdir")
+    except KeyError:
+        log.debug("Unable to find productdir in registry")
+        productdir = None
+
+    if not productdir or not os.path.isdir(productdir):
+        toolskey = "VS%0.f0COMNTOOLS" % version
+        toolsdir = os.environ.get(toolskey, None)
+
+        if toolsdir and os.path.isdir(toolsdir):
+            productdir = os.path.join(toolsdir, os.pardir, os.pardir, "VC")
+            productdir = os.path.abspath(productdir)
+            if not os.path.isdir(productdir):
+                log.debug("%s is not a valid directory" % productdir)
+                return None
+        else:
+            log.debug("Env var %s is not set or invalid" % toolskey)
+    if not productdir:
+        log.debug("No productdir found")
+        return None
+    vcvarsall = os.path.join(productdir, "vcvarsall.bat")
+    if os.path.isfile(vcvarsall):
+        return vcvarsall
+    log.debug("Unable to find vcvarsall.bat")
+    return None
+
+def query_vcvarsall(version, arch="x86"):
+    """Launch vcvarsall.bat and read the settings from its environment
+    """
+    vcvarsall = find_vcvarsall(version)
+    interesting = set(("include", "lib", "libpath", "path"))
+    result = {}
+
+    if vcvarsall is None:
+        raise IOError("Unable to find vcvarsall.bat")
+    popen = subprocess.Popen('"%s" %s & set' % (vcvarsall, arch),
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+    if popen.wait() != 0:
+        raise IOError(popen.stderr.read())
+
+    for line in popen.stdout:
+        line = Reg.convert_mbcs(line)
+        if '=' not in line:
+            continue
+        line = line.strip()
+        key, value = line.split('=')
+        key = key.lower()
+        if key in interesting:
+            if value.endswith(os.pathsep):
+                value = value[:-1]
+            result[key] = value
+
+    if len(result) != len(interesting):
+        raise ValueError(str(list(result.keys())))
+
+    return result
+
+# More globals
+VERSION = get_build_version()
+if VERSION < 8.0:
+    raise DistutilsPlatformError("VC %0.1f is not supported by this module" % VERSION)
+ARCH = get_build_architecture()
+# MACROS = MacroExpander(VERSION)
+VC_ENV = query_vcvarsall(VERSION, ARCH)
+
+class MSVCCompiler(CCompiler) :
+    """Concrete class that implements an interface to Microsoft Visual C++,
+       as defined by the CCompiler abstract class."""
+
+    compiler_type = 'msvc'
+
+    # Just set this so CCompiler's constructor doesn't barf.  We currently
+    # don't use the 'set_executables()' bureaucracy provided by CCompiler,
+    # as it really isn't necessary for this sort of single-compiler class.
+    # Would be nice to have a consistent interface with UnixCCompiler,
+    # though, so it's worth thinking about.
+    executables = {}
+
+    # Private class data (need to distinguish C from C++ source for compiler)
+    _c_extensions = ['.c']
+    _cpp_extensions = ['.cc', '.cpp', '.cxx']
+    _rc_extensions = ['.rc']
+    _mc_extensions = ['.mc']
+
+    # Needed for the filename generation methods provided by the
+    # base class, CCompiler.
+    src_extensions = (_c_extensions + _cpp_extensions +
+                      _rc_extensions + _mc_extensions)
+    res_extension = '.res'
+    obj_extension = '.obj'
+    static_lib_extension = '.lib'
+    shared_lib_extension = '.dll'
+    static_lib_format = shared_lib_format = '%s%s'
+    exe_extension = '.exe'
+
+    def __init__(self, verbose=0, dry_run=0, force=0):
+        CCompiler.__init__ (self, verbose, dry_run, force)
+        self.__version = VERSION
+        self.__arch = ARCH
+        self.__root = r"Software\Microsoft\VisualStudio"
+        # self.__macros = MACROS
+        self.__path = []
+        self.initialized = False
+
+    def initialize(self):
+        if "DISTUTILS_USE_SDK" in os.environ and "MSSdk" in os.environ and self.find_exe("cl.exe"):
+            # Assume that the SDK set up everything alright; don't try to be
+            # smarter
+            self.cc = "cl.exe"
+            self.linker = "link.exe"
+            self.lib = "lib.exe"
+            self.rc = "rc.exe"
+            self.mc = "mc.exe"
+        else:
+            self.__paths = VC_ENV['path'].split(os.pathsep)
+            os.environ['lib'] = VC_ENV['lib']
+            os.environ['include'] = VC_ENV['include']
+
+            if len(self.__paths) == 0:
+                raise DistutilsPlatformError("Python was built with %s, "
+                       "and extensions need to be built with the same "
+                       "version of the compiler, but it isn't installed."
+                       % self.__product)
+
+            self.cc = self.find_exe("cl.exe")
+            self.linker = self.find_exe("link.exe")
+            self.lib = self.find_exe("lib.exe")
+            self.rc = self.find_exe("rc.exe")   # resource compiler
+            self.mc = self.find_exe("mc.exe")   # message compiler
+            #self.set_path_env_var('lib')
+            #self.set_path_env_var('include')
+
+        # extend the MSVC path with the current path
+        try:
+            for p in os.environ['path'].split(';'):
+                self.__paths.append(p)
+        except KeyError:
+            pass
+        self.__paths = normalize_and_reduce_paths(self.__paths)
+        os.environ['path'] = ";".join(self.__paths)
+
+        self.preprocess_options = None
+        if self.__arch == "x86":
+            self.compile_options = [ '/nologo', '/Ox', '/MD', '/W3',
+                                     '/DNDEBUG']
+            self.compile_options_debug = ['/nologo', '/Od', '/MDd', '/W3',
+                                          '/Z7', '/D_DEBUG']
+        else:
+            # Win64
+            self.compile_options = [ '/nologo', '/Ox', '/MD', '/W3', '/GS-' ,
+                                     '/DNDEBUG']
+            self.compile_options_debug = ['/nologo', '/Od', '/MDd', '/W3', '/GS-',
+                                          '/Z7', '/D_DEBUG']
+
+        self.ldflags_shared = ['/DLL', '/nologo', '/INCREMENTAL:NO']
+        if self.__version >= 7:
+            self.ldflags_shared_debug = [
+                '/DLL', '/nologo', '/INCREMENTAL:no', '/DEBUG', '/pdb:None'
+                ]
+        self.ldflags_static = [ '/nologo']
+
+        self.initialized = True
+
+    # -- Worker methods ------------------------------------------------
+
+    def object_filenames(self,
+                         source_filenames,
+                         strip_dir=0,
+                         output_dir=''):
+        # Copied from ccompiler.py, extended to return .res as 'object'-file
+        # for .rc input file
+        if output_dir is None: output_dir = ''
+        obj_names = []
+        for src_name in source_filenames:
+            (base, ext) = os.path.splitext (src_name)
+            base = os.path.splitdrive(base)[1] # Chop off the drive
+            base = base[os.path.isabs(base):]  # If abs, chop off leading /
+            if ext not in self.src_extensions:
+                # Better to raise an exception instead of silently continuing
+                # and later complain about sources and targets having
+                # different lengths
+                raise CompileError ("Don't know how to compile %s" % src_name)
+            if strip_dir:
+                base = os.path.basename (base)
+            if ext in self._rc_extensions:
+                obj_names.append (os.path.join (output_dir,
+                                                base + self.res_extension))
+            elif ext in self._mc_extensions:
+                obj_names.append (os.path.join (output_dir,
+                                                base + self.res_extension))
+            else:
+                obj_names.append (os.path.join (output_dir,
+                                                base + self.obj_extension))
+        return obj_names
+
+
+    def compile(self, sources,
+                output_dir=None, macros=None, include_dirs=None, debug=0,
+                extra_preargs=None, extra_postargs=None, depends=None):
+
+        if not self.initialized:
+            self.initialize()
+        compile_info = self._setup_compile(output_dir, macros, include_dirs,
+                                           sources, depends, extra_postargs)
+        macros, objects, extra_postargs, pp_opts, build = compile_info
+
+        compile_opts = extra_preargs or []
+        compile_opts.append ('/c')
+        if debug:
+            compile_opts.extend(self.compile_options_debug)
+        else:
+            compile_opts.extend(self.compile_options)
+
+        for obj in objects:
+            try:
+                src, ext = build[obj]
+            except KeyError:
+                continue
+            if debug:
+                # pass the full pathname to MSVC in debug mode,
+                # this allows the debugger to find the source file
+                # without asking the user to browse for it
+                src = os.path.abspath(src)
+
+            if ext in self._c_extensions:
+                input_opt = "/Tc" + src
+            elif ext in self._cpp_extensions:
+                input_opt = "/Tp" + src
+            elif ext in self._rc_extensions:
+                # compile .RC to .RES file
+                input_opt = src
+                output_opt = "/fo" + obj
+                try:
+                    self.spawn([self.rc] + pp_opts +
+                               [output_opt] + [input_opt])
+                except DistutilsExecError as msg:
+                    raise CompileError(msg)
+                continue
+            elif ext in self._mc_extensions:
+                # Compile .MC to .RC file to .RES file.
+                #   * '-h dir' specifies the directory for the
+                #     generated include file
+                #   * '-r dir' specifies the target directory of the
+                #     generated RC file and the binary message resource
+                #     it includes
+                #
+                # For now (since there are no options to change this),
+                # we use the source-directory for the include file and
+                # the build directory for the RC file and message
+                # resources. This works at least for win32all.
+                h_dir = os.path.dirname(src)
+                rc_dir = os.path.dirname(obj)
+                try:
+                    # first compile .MC to .RC and .H file
+                    self.spawn([self.mc] +
+                               ['-h', h_dir, '-r', rc_dir] + [src])
+                    base, _ = os.path.splitext (os.path.basename (src))
+                    rc_file = os.path.join (rc_dir, base + '.rc')
+                    # then compile .RC to .RES file
+                    self.spawn([self.rc] +
+                               ["/fo" + obj] + [rc_file])
+
+                except DistutilsExecError as msg:
+                    raise CompileError(msg)
+                continue
+            else:
+                # how to handle this file?
+                raise CompileError("Don't know how to compile %s to %s"
+                                   % (src, obj))
+
+            output_opt = "/Fo" + obj
+            try:
+                self.spawn([self.cc] + compile_opts + pp_opts +
+                           [input_opt, output_opt] +
+                           extra_postargs)
+            except DistutilsExecError as msg:
+                raise CompileError(msg)
+
+        return objects
+
+
+    def create_static_lib(self,
+                          objects,
+                          output_libname,
+                          output_dir=None,
+                          debug=0,
+                          target_lang=None):
+
+        if not self.initialized:
+            self.initialize()
+        (objects, output_dir) = self._fix_object_args(objects, output_dir)
+        output_filename = self.library_filename(output_libname,
+                                                output_dir=output_dir)
+
+        if self._need_link(objects, output_filename):
+            lib_args = objects + ['/OUT:' + output_filename]
+            if debug:
+                pass # XXX what goes here?
+            try:
+                self.spawn([self.lib] + lib_args)
+            except DistutilsExecError as msg:
+                raise LibError(msg)
+        else:
+            log.debug("skipping %s (up-to-date)", output_filename)
+
+
+    def link(self,
+             target_desc,
+             objects,
+             output_filename,
+             output_dir=None,
+             libraries=None,
+             library_dirs=None,
+             runtime_library_dirs=None,
+             export_symbols=None,
+             debug=0,
+             extra_preargs=None,
+             extra_postargs=None,
+             build_temp=None,
+             target_lang=None):
+
+        if not self.initialized:
+            self.initialize()
+        (objects, output_dir) = self._fix_object_args(objects, output_dir)
+        fixed_args = self._fix_lib_args(libraries, library_dirs,
+                                        runtime_library_dirs)
+        (libraries, library_dirs, runtime_library_dirs) = fixed_args
+
+        if runtime_library_dirs:
+            self.warn ("I don't know what to do with 'runtime_library_dirs': "
+                       + str (runtime_library_dirs))
+
+        lib_opts = gen_lib_options(self,
+                                   library_dirs, runtime_library_dirs,
+                                   libraries)
+        if output_dir is not None:
+            output_filename = os.path.join(output_dir, output_filename)
+
+        if self._need_link(objects, output_filename):
+            if target_desc == CCompiler.EXECUTABLE:
+                if debug:
+                    ldflags = self.ldflags_shared_debug[1:]
+                else:
+                    ldflags = self.ldflags_shared[1:]
+            else:
+                if debug:
+                    ldflags = self.ldflags_shared_debug
+                else:
+                    ldflags = self.ldflags_shared
+
+            export_opts = []
+            for sym in (export_symbols or []):
+                export_opts.append("/EXPORT:" + sym)
+
+            ld_args = (ldflags + lib_opts + export_opts +
+                       objects + ['/OUT:' + output_filename])
+
+            # The MSVC linker generates .lib and .exp files, which cannot be
+            # suppressed by any linker switches. The .lib files may even be
+            # needed! Make sure they are generated in the temporary build
+            # directory. Since they have different names for debug and release
+            # builds, they can go into the same directory.
+            if export_symbols is not None:
+                (dll_name, dll_ext) = os.path.splitext(
+                    os.path.basename(output_filename))
+                implib_file = os.path.join(
+                    os.path.dirname(objects[0]),
+                    self.library_filename(dll_name))
+                ld_args.append ('/IMPLIB:' + implib_file)
+
+            if extra_preargs:
+                ld_args[:0] = extra_preargs
+            if extra_postargs:
+                ld_args.extend(extra_postargs)
+
+            self.mkpath(os.path.dirname(output_filename))
+            try:
+                self.spawn([self.linker] + ld_args)
+            except DistutilsExecError as msg:
+                raise LinkError(msg)
+
+        else:
+            log.debug("skipping %s (up-to-date)", output_filename)
+
+
+    # -- Miscellaneous methods -----------------------------------------
+    # These are all used by the 'gen_lib_options() function, in
+    # ccompiler.py.
+
+    def library_dir_option(self, dir):
+        return "/LIBPATH:" + dir
+
+    def runtime_library_dir_option(self, dir):
+        raise DistutilsPlatformError(
+              "don't know how to set runtime library search path for MSVC++")
+
+    def library_option(self, lib):
+        return self.library_filename(lib)
+
+
+    def find_library_file(self, dirs, lib, debug=0):
+        # Prefer a debugging library if found (and requested), but deal
+        # with it if we don't have one.
+        if debug:
+            try_names = [lib + "_d", lib]
+        else:
+            try_names = [lib]
+        for dir in dirs:
+            for name in try_names:
+                libfile = os.path.join(dir, self.library_filename (name))
+                if os.path.exists(libfile):
+                    return libfile
+        else:
+            # Oops, didn't find it in *any* of 'dirs'
+            return None
+
+    # Helper methods for using the MSVC registry settings
+
+    def find_exe(self, exe):
+        """Return path to an MSVC executable program.
+
+        Tries to find the program in several places: first, one of the
+        MSVC program search paths from the registry; next, the directories
+        in the PATH environment variable.  If any of those work, return an
+        absolute path that is known to exist.  If none of them work, just
+        return the original program name, 'exe'.
+        """
+        for p in self.__paths:
+            fn = os.path.join(os.path.abspath(p), exe)
+            if os.path.isfile(fn):
+                return fn
+
+        # didn't find it; try existing path
+        for p in os.environ['Path'].split(';'):
+            fn = os.path.join(os.path.abspath(p),exe)
+            if os.path.isfile(fn):
+                return fn
+
+        return exe
diff --git a/Lib/test/exception_hierarchy.txt b/Lib/test/exception_hierarchy.txt
index 965252c..73ccb66 100644
--- a/Lib/test/exception_hierarchy.txt
+++ b/Lib/test/exception_hierarchy.txt
@@ -1,8 +1,8 @@
 BaseException
  +-- SystemExit
  +-- KeyboardInterrupt
+ +-- GeneratorExit
  +-- Exception
-      +-- GeneratorExit
       +-- StopIteration
       +-- ArithmeticError
       |    +-- FloatingPointError
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 4710c8c..0d6908d 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -1668,6 +1668,19 @@ And finalization:
 exiting
 
 
+GeneratorExit is not caught by except Exception:
+
+>>> def f():
+...     try: yield
+...     except Exception: print 'except'
+...     finally: print 'finally'
+
+>>> g = f()
+>>> g.next()
+>>> del g
+finally
+
+
 Now let's try some ill-behaved generators:
 
 >>> def f():
diff --git a/Misc/NEWS b/Misc/NEWS
index 465026a..0c6dd45 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -245,6 +245,8 @@ Extension Modules
   * operator module: div, idiv, __div__, __idiv__, isCallable, sequenceIncludes
   * sys module: exc_clear(), exc_type, exc_value, exc_traceback
 
+- Issue #1537: Changed GeneratorExit's base class from Exception to BaseException.
+
 
 Library
 -------
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 4c6a122..cbcda7b 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -424,9 +424,9 @@ SimpleExtendsException(PyExc_Exception, StopIteration,
 
 
 /*
- *    GeneratorExit extends Exception
+ *    GeneratorExit extends BaseException
  */
-SimpleExtendsException(PyExc_Exception, GeneratorExit,
+SimpleExtendsException(PyExc_BaseException, GeneratorExit,
                        "Request that a generator exit.");