Kernelspec handle case where folder already exists

Prevent crash if trying to install-self on already self-installed

IPython/kernel/kernelspecapp.py

@@ -1,145 +1,148 b''
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import errno
 import os.path
 
 from IPython.config.application import Application
 from IPython.core.application import (
     BaseIPythonApplication, base_flags, base_aliases
 )
 from IPython.utils.traitlets import Instance, Dict, Unicode, Bool
 
 from .kernelspec import KernelSpecManager, _pythonfirst
 
 class ListKernelSpecs(BaseIPythonApplication):
     description = """List installed kernel specifications."""
     kernel_spec_manager = Instance(KernelSpecManager)
-    
+
     # Not all of the base aliases are meaningful (e.g. profile)
     aliases = {k: base_aliases[k] for k in ['ipython-dir', 'log-level']}
     flags = {'debug': base_flags['debug'],}
 
     def _kernel_spec_manager_default(self):
         return KernelSpecManager(ipython_dir=self.ipython_dir)
 
     def start(self):
         print("Available kernels:")
         for kernelname in sorted(self.kernel_spec_manager.find_kernel_specs(),
                                  key=_pythonfirst):
             print("  %s" % kernelname)
 
 
 class InstallKernelSpec(BaseIPythonApplication):
     description = """Install a kernel specification directory."""
     kernel_spec_manager = Instance(KernelSpecManager)
 
     def _kernel_spec_manager_default(self):
         return KernelSpecManager(ipython_dir=self.ipython_dir)
 
     sourcedir = Unicode()
     kernel_name = Unicode("", config=True,
         help="Install the kernel spec with this name"
     )
     def _kernel_name_default(self):
         return os.path.basename(self.sourcedir)
 
     system = Bool(False, config=True,
         help="""
         Try to install the kernel spec to the systemwide directory instead of
         the per-user directory.
         """
     )
     replace = Bool(False, config=True,
         help="Replace any existing kernel spec with this name."
     )
 
     aliases = {'name': 'InstallKernelSpec.kernel_name'}
     for k in ['ipython-dir', 'log-level']:
         aliases[k] = base_aliases[k]
 
     flags = {'system': ({'InstallKernelSpec': {'system': True}},
                 "Install to the systemwide kernel registry"),
              'replace': ({'InstallKernelSpec': {'replace': True}},
                 "Replace any existing kernel spec with this name."),
              'debug': base_flags['debug'],
             }
 
     def parse_command_line(self, argv):
         super(InstallKernelSpec, self).parse_command_line(argv)
         # accept positional arg as profile name
         if self.extra_args:
             self.sourcedir = self.extra_args[0]
         else:
             print("No source directory specified.")
             self.exit(1)
 
     def start(self):
         try:
             self.kernel_spec_manager.install_kernel_spec(self.sourcedir,
                                                  kernel_name=self.kernel_name,
                                                  system=self.system,
                                                  replace=self.replace,
                                                 )
         except OSError as e:
             if e.errno == errno.EACCES:
                 print("Permission denied")
                 self.exit(1)
             elif e.errno == errno.EEXIST:
                 print("A kernel spec is already present at %s" % e.filename)
                 self.exit(1)
             raise
 
 class InstallNativeKernelSpec(BaseIPythonApplication):
     description = """Install the native kernel spec directory for this Python."""
     kernel_spec_manager = Instance(KernelSpecManager)
 
     def _kernel_spec_manager_default(self):
         return KernelSpecManager(ipython_dir=self.ipython_dir)
 
     system = Bool(False, config=True,
         help="""
         Try to install the kernel spec to the systemwide directory instead of
         the per-user directory.
         """
     )
 
     # Not all of the base aliases are meaningful (e.g. profile)
     aliases = {k: base_aliases[k] for k in ['ipython-dir', 'log-level']}
     flags = {'system': ({'InstallOwnKernelSpec': {'system': True}},
                 "Install to the systemwide kernel registry"),
              'debug': base_flags['debug'],
             }
 
     def start(self):
         try:
             self.kernel_spec_manager.install_native_kernel_spec(system=self.system)
         except OSError as e:
             if e.errno == errno.EACCES:
                 print("Permission denied")
                 self.exit(1)
+            if e.errno == errno.EEXIST:
+                print("File or folder already exists")
+                self.exit(1)
             raise
 
 class KernelSpecApp(Application):
     name = "ipython kernelspec"
     description = """Manage IPython kernel specifications."""
 
     subcommands = Dict({
         'list': (ListKernelSpecs, ListKernelSpecs.description.splitlines()[0]),
         'install': (InstallKernelSpec, InstallKernelSpec.description.splitlines()[0]),
         'install-self': (InstallNativeKernelSpec, InstallNativeKernelSpec.description.splitlines()[0]),
     })
 
     aliases = {}
     flags = {}
 
     def start(self):
         if self.subapp is None:
             print("No subcommand specified. Must specify one of: %s"% list(self.subcommands))
             print()
             self.print_description()
             self.print_subcommands()
             self.exit(1)
         else:
             return self.subapp.start()