Merge pull request #8244 from minrk/shutil.which

add shutil.which backport to py3compat

IPython/testing/decorators.py

@@ -26,32 +26,16 b' IPython.external.decorators, we import either numpy.testing.decorators if numpy '
 available, OR use equivalent code in IPython.external._decorators, which
 we've copied verbatim from numpy.
 
-Authors
--------
-
-- Fernando Perez <[e-mail]>
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2009-2011  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.
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
-
-# Stdlib imports
 import sys
 import os
 import tempfile
 import unittest
 
-# Third-party imports
-
-# This is Michele Simionato's decorator module, kept verbatim.
 from decorator import decorator
 
 # Expose the unittest-driven decorators
@@ -63,8 +47,7 b' from .ipunittest import ipdoctest, ipdocstring'
 from IPython.external.decorators import *
 
 # For onlyif_cmd_exists decorator
-from IPython.utils.process import is_cmd_found
-from IPython.utils.py3compat import string_types
+from IPython.utils.py3compat import string_types, which
 
 #-----------------------------------------------------------------------------
 # Classes and functions
@@ -370,16 +353,9 b' def onlyif_cmds_exist(*commands):'
     Decorator to skip test when at least one of `commands` is not found.
     """
     for cmd in commands:
-        try:
-            if not is_cmd_found(cmd):
-                return skip("This test runs only if command '{0}' "
-                            "is installed".format(cmd))
-        except ImportError as e:
-            # is_cmd_found uses pywin32 on windows, which might not be available
-            if sys.platform == 'win32' and 'pywin32' in str(e):
-                return skip("This test runs only if pywin32 and command '{0}' "
-                            "is installed".format(cmd))
-            raise e
+        if not which(cmd):
+            return skip("This test runs only if command '{0}' "
+                        "is installed".format(cmd))
     return null_deco
 
 def onlyif_any_cmd_exists(*commands):
@@ -387,14 +363,7 b' def onlyif_any_cmd_exists(*commands):'
     Decorator to skip test unless at least one of `commands` is found.
     """
     for cmd in commands:
-        try:
-            if is_cmd_found(cmd):
-                return null_deco
-        except ImportError as e:
-            # is_cmd_found uses pywin32 on windows, which might not be available
-            if sys.platform == 'win32' and 'pywin32' in str(e):
-                return skip("This test runs only if pywin32 and commands '{0}' "
-                            "are installed".format(commands))
-            raise e
+        if which(cmd):
+            return null_deco
     return skip("This test runs only if one of the commands {0} "
                 "is installed".format(commands))

IPython/utils/process.py

@@ -3,37 +3,24 b''
 Utilities for working with external processes.
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2011  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
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
 from __future__ import print_function
 
-# Stdlib
 import os
 import sys
 
-# Our own
 if sys.platform == 'win32':
-    from ._process_win32 import _find_cmd, system, getoutput, arg_split, check_pid
+    from ._process_win32 import system, getoutput, arg_split, check_pid
 elif sys.platform == 'cli':
-    from ._process_cli import _find_cmd, system, getoutput, arg_split, check_pid
+    from ._process_cli import system, getoutput, arg_split, check_pid
 else:
-    from ._process_posix import _find_cmd, system, getoutput, arg_split, check_pid
+    from ._process_posix import system, getoutput, arg_split, check_pid
 
 from ._process_common import getoutputerror, get_output_error_code, process_handler
 from . import py3compat
 
-#-----------------------------------------------------------------------------
-# Code
-#-----------------------------------------------------------------------------
-
 
 class FindCmdError(Exception):
     pass
@@ -59,14 +46,10 b' def find_cmd(cmd):'
     cmd : str
         The command line program to look for.
     """
-    try:
-        path = _find_cmd(cmd).rstrip()
-    except OSError:
-        raise FindCmdError('command could not be found: %s' % cmd)
-    # which returns empty if not found
-    if path == '':
+    path = py3compat.which(cmd)
+    if path is None:
         raise FindCmdError('command could not be found: %s' % cmd)
-    return os.path.abspath(path)
+    return path
 
 
 def is_cmd_found(cmd):

IPython/utils/py3compat.py

@@ -4,6 +4,7 b' import functools'
 import os
 import sys
 import re
+import shutil
 import types
 
 from .encoding import DEFAULT_ENCODING
@@ -75,6 +76,70 b' def safe_unicode(e):'
 
     return u'Unrecoverably corrupt evalue'
 
+# shutil.which from Python 3.4
+def _shutil_which(cmd, mode=os.F_OK | os.X_OK, path=None):
+    """Given a command, mode, and a PATH string, return the path which
+    conforms to the given mode on the PATH, or None if there is no such
+    file.
+
+    `mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
+    of os.environ.get("PATH"), or can be overridden with a custom search
+    path.
+    
+    This is a backport of shutil.which from Python 3.4
+    """
+    # Check that a given file can be accessed with the correct mode.
+    # Additionally check that `file` is not a directory, as on Windows
+    # directories pass the os.access check.
+    def _access_check(fn, mode):
+        return (os.path.exists(fn) and os.access(fn, mode)
+                and not os.path.isdir(fn))
+
+    # If we're given a path with a directory part, look it up directly rather
+    # than referring to PATH directories. This includes checking relative to the
+    # current directory, e.g. ./script
+    if os.path.dirname(cmd):
+        if _access_check(cmd, mode):
+            return cmd
+        return None
+
+    if path is None:
+        path = os.environ.get("PATH", os.defpath)
+    if not path:
+        return None
+    path = path.split(os.pathsep)
+
+    if sys.platform == "win32":
+        # The current directory takes precedence on Windows.
+        if not os.curdir in path:
+            path.insert(0, os.curdir)
+
+        # PATHEXT is necessary to check on Windows.
+        pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
+        # See if the given file matches any of the expected path extensions.
+        # This will allow us to short circuit when given "python.exe".
+        # If it does match, only test that one, otherwise we have to try
+        # others.
+        if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
+            files = [cmd]
+        else:
+            files = [cmd + ext for ext in pathext]
+    else:
+        # On other platforms you don't have things like PATHEXT to tell you
+        # what file suffixes are executable, so just pass on cmd as-is.
+        files = [cmd]
+
+    seen = set()
+    for dir in path:
+        normdir = os.path.normcase(dir)
+        if not normdir in seen:
+            seen.add(normdir)
+            for thefile in files:
+                name = os.path.join(dir, thefile)
+                if _access_check(name, mode):
+                    return name
+    return None
+
 if sys.version_info[0] >= 3:
     PY3 = True
     
@@ -97,6 +162,8 b' if sys.version_info[0] >= 3:'
     string_types = (str,)
     unicode_type = str
     
+    which = shutil.which
+    
     def isidentifier(s, dotted=False):
         if dotted:
             return all(isidentifier(a) for a in s.split("."))
@@ -184,6 +251,8 b' else:'
     def get_closure(f):
         """Get a function's closure attribute"""
         return f.func_closure
+    
+    which = _shutil_which
 
     # Abstract u'abc' syntax:
     @_modify_str_or_docstring

IPython/utils/tests/test_process.py

@@ -52,7 +52,7 b' def has_pywin32():'
 def test_find_cmd_pythonw():
     """Try to find pythonw on Windows."""
     path = find_cmd('pythonw')
-    nt.assert_true(path.endswith('pythonw.exe'))
+    assert path.lower().endswith('pythonw.exe'), path
 
 
 @dec.onlyif(lambda : sys.platform != 'win32' or has_pywin32(),

jupyter_nbconvert/exporters/pdf.py

@@ -7,7 +7,7 b' import subprocess'
 import os
 import sys
 
-from IPython.utils.process import find_cmd
+from IPython.utils.py3compat import which
 from IPython.utils.traitlets import Integer, List, Bool, Instance
 from IPython.utils.tempdir import TemporaryWorkingDirectory
 from .latex import LatexExporter
@@ -65,10 +65,12 b' class PDFExporter(LatexExporter):'
             #We must use cp1252 encoding for calling subprocess.Popen
             #Note that sys.stdin.encoding and encoding.DEFAULT_ENCODING
             # could be different (cp437 in case of dos console)
-            command = [c.encode('cp1252') for c in command]        
+            command = [c.encode('cp1252') for c in command]
 
         # This will throw a clearer error if the command is not found
-        find_cmd(command_list[0])
+        cmd = which(command_list[0])
+        if cmd is None:
+            raise OSError("%s not found on PATH" % command_list[0])
         
         times = 'time' if count == 1 else 'times'
         self.log.info("Running %s %i %s: %s", command_list[0], count, times, command)