Fix windows concurrency issues

pipenv/cli.py

@@ -32,7 +32,7 @@ from .project import Project
 from .utils import (
     convert_deps_from_pip, convert_deps_to_pip, is_required_version,
     proper_case, pep423_name, split_vcs, resolve_deps, shellquote, is_vcs,
-    python_version, suggest_package
+    python_version, suggest_package, find_windows_executable
 )
 from .__version__ import __version__
 from . import pep508checker, progress
@@ -1136,10 +1136,6 @@ def pip_install(
     no_deps=True, verbose=False, block=True
 ):
 
-    # Block is always true on windows, for there be bugs.
-    if os.name == 'nt':
-        block=True
-
     # Create files for hash mode.
     if (not ignore_hashes) and (r is None):
         r = tempfile.mkstemp(prefix='pipenv-', suffix='-requirement.txt')[1]
@@ -1173,8 +1169,12 @@ def pip_install(
 
         no_deps = '--no-deps' if no_deps else ''
 
-        pip_command = '"{0}" install {3} {1} -i {2} --exists-action w'.format(
-            which_pip(allow_global=allow_global),
+        quoted_pip = which_pip(allow_global=allow_global)
+        if os.name != 'nt':
+            quoted_pip = shellquote(quoted_pip)
+
+        pip_command = '{0} install {3} {1} -i {2} --exists-action w'.format(
+            quoted_pip,
             install_reqs,
             source['url'],
             no_deps
@@ -1211,10 +1211,7 @@ def which(command, location=None, allow_global=False):
 
     if not allow_global:
         if os.name == 'nt':
-            if command.endswith('.py'):
-                p = os.sep.join([location] + ['Scripts\{0}'.format(command)])
-            else:
-                p = os.sep.join([location] + ['Scripts\{0}.exe'.format(command)])
+            p = find_windows_executable(os.path.join(location, 'Scripts'), command)
         else:
             p = os.sep.join([location] + ['bin/{0}'.format(command)])
     else:

pipenv/utils.py

@@ -538,6 +538,28 @@ def recase_file(file_dict):
     return file_dict
 
 
+def get_windows_path(*args):
+    """Sanitize a path for windows environments
+
+    Accepts an arbitrary list of arguments and makes a clean windows path"""
+    clean_path = os.path.join(*args)
+    return os.path.normpath(clean_path)
+
+
+def find_windows_executable(bin_path, exe_name):
+    """Given an executable name, search the given location for an executable"""
+    requested_path = get_windows_path(bin_path, exe_name)
+    if os.path.exists(requested_path):
+        return requested_path
+
+    # Ensure we aren't adding two layers of file extensions
+    exe_name = os.path.splitext(exe_name)[0]
+    files = ['{0}.{1}'.format(exe_name, ext) for ext in ['', 'py', 'exe', 'bat']]
+    exec_paths = [get_windows_path(bin_path, f) for f in files]
+    exec_files = [filename for filename in exec_paths if os.path.isfile(filename)]
+    return exec_files[0]
+
+
 def walk_up(bottom):
     """Mimic os.walk, but walk 'up' instead of down the directory tree.
     From: https://gist.github.com/zdavkeos/1098474