Merge with updates

Signed-off-by: Dan Ryan <dan@danryan.co>

.gitignore

@@ -153,3 +153,8 @@ venv.bak/
 
 # Custom rules (everything added below won't be overriden by 'Generate .gitignore File' if you use 'Update' option)
 .vs/slnx.sqlite
+
+# mypy/typing section
+typeshed/
+.dmypy.json
+mypyhtml/

pipenv/environment.py

@@ -163,7 +163,7 @@ def base_paths(self):
         paths["libdir"] = purelib
         paths["purelib"] = purelib
         paths["platlib"] = platlib
-        paths['PYTHONPATH'] = lib_dirs
+        paths['PYTHONPATH'] = os.pathsep.join(["", ".", lib_dirs])
         paths["libdirs"] = lib_dirs
         return paths
 
@@ -526,6 +526,7 @@ def activated(self, include_extras=True, extra_dists=None):
         vendor_dir = parent_path.joinpath("vendor").as_posix()
         patched_dir = parent_path.joinpath("patched").as_posix()
         parent_path = parent_path.as_posix()
+        self.add_dist("pip")
         prefix = self.prefix.as_posix()
         with vistir.contextmanagers.temp_environ(), vistir.contextmanagers.temp_path():
             os.environ["PATH"] = os.pathsep.join([
@@ -535,12 +536,24 @@ def activated(self, include_extras=True, extra_dists=None):
             ])
             os.environ["PYTHONIOENCODING"] = vistir.compat.fs_str("utf-8")
             os.environ["PYTHONDONTWRITEBYTECODE"] = vistir.compat.fs_str("1")
-            os.environ["PYTHONPATH"] = self.base_paths["PYTHONPATH"]
+            from .environments import PIPENV_USE_SYSTEM
             if self.is_venv:
+                os.environ["PYTHONPATH"] = self.base_paths["PYTHONPATH"]
                 os.environ["VIRTUAL_ENV"] = vistir.compat.fs_str(prefix)
+            else:
+                if not PIPENV_USE_SYSTEM and not os.environ.get("VIRTUAL_ENV"):
+                    os.environ["PYTHONPATH"] = self.base_paths["PYTHONPATH"]
+                    os.environ.pop("PYTHONHOME", None)
             sys.path = self.sys_path
             sys.prefix = self.sys_prefix
             site.addsitedir(self.base_paths["purelib"])
+            pip = self.safe_import("pip")
+            pip_vendor = self.safe_import("pip._vendor")
+            pep517_dir = os.path.join(os.path.dirname(pip_vendor.__file__), "pep517")
+            site.addsitedir(pep517_dir)
+            os.environ["PYTHONPATH"] = os.pathsep.join([
+                os.environ.get("PYTHONPATH", self.base_paths["PYTHONPATH"]), pep517_dir
+            ])
             if include_extras:
                 site.addsitedir(parent_path)
                 sys.path.extend([parent_path, patched_dir, vendor_dir])

pipenv/environments.py

@@ -280,13 +280,37 @@ def is_quiet(threshold=-1):
 
 
 def is_in_virtualenv():
-    pipenv_active = os.environ.get("PIPENV_ACTIVE")
-    virtual_env = os.environ.get("VIRTUAL_ENV")
-    return (PIPENV_USE_SYSTEM or virtual_env) and not (
-        pipenv_active or PIPENV_IGNORE_VIRTUALENVS
+    """
+    Check virtualenv membership dynamically
+
+    :return: True or false depending on whether we are in a regular virtualenv or not
+    :rtype: bool
+    """
+
+    pipenv_active = os.environ.get("PIPENV_ACTIVE", False)
+    virtual_env = None
+    use_system = False
+    ignore_virtualenvs = bool(os.environ.get("PIPENV_IGNORE_VIRTUALENVS", False))
+
+    if not pipenv_active and not ignore_virtualenvs:
+        virtual_env = os.environ.get("VIRTUAL_ENV")
+        use_system = bool(virtual_env)
+    return (use_system or virtual_env) and not (
+        pipenv_active or ignore_virtualenvs
     )
 
 
 PIPENV_SPINNER_FAIL_TEXT = fix_utf8(u"✘ {0}") if not PIPENV_HIDE_EMOJIS else ("{0}")
 
 PIPENV_SPINNER_OK_TEXT = fix_utf8(u"✔ {0}") if not PIPENV_HIDE_EMOJIS else ("{0}")
+
+
+def is_type_checking():
+    try:
+        from typing import TYPE_CHECKING
+    except ImportError:
+        return False
+    return TYPE_CHECKING
+
+
+MYPY_RUNNING = is_type_checking()