Decouple project from the existence of Pipfile.

news/3386.behavior.rst

@@ -0,0 +1 @@
+Do not touch Pipfile early and rely on it so that one can do ``pipenv sync`` without a Pipfile.

news/3434.trivial.rst

@@ -0,0 +1 @@
+Improve the error message when one tries to initialize a Pipenv project under ``/``.

pipenv/cli/command.py

@@ -152,7 +152,11 @@ def cli(
             # There is no virtualenv yet.
             if not project.virtualenv_exists:
                 echo(
-                    crayons.red("No virtualenv has been created for this project yet!"),
+                    "{}({}){}".format(
+                        crayons.red("No virtualenv has been created for this project"),
+                        crayons.white(project.project_directory, bold=True),
+                        crayons.red(" yet!")
+                    ),
                     err=True,
                 )
                 ctx.abort()

pipenv/core.py

@@ -539,11 +539,16 @@ def ensure_project(
     # Automatically use an activated virtualenv.
     if PIPENV_USE_SYSTEM:
         system = True
-    if not project.pipfile_exists:
-        if deploy is True:
-            raise exceptions.PipfileNotFound
-        else:
-            project.touch_pipfile()
+    if not project.pipfile_exists and deploy:
+        raise exceptions.PipfileNotFound
+    # Fail if working under /
+    if not project.name:
+        click.echo(
+            "{0}: Pipenv is not intended to work under the root directory, "
+            "please choose another path.".format(crayons.red("ERROR")),
+            err=True
+        )
+        sys.exit(1)
     # Skip virtualenv creation when --system was used.
     if not system:
         ensure_virtualenv(
@@ -606,24 +611,23 @@ def shorten_path(location, bold=False):
 def do_where(virtualenv=False, bare=True):
     """Executes the where functionality."""
     if not virtualenv:
-        location = project.pipfile_location
-        # Shorten the virtual display of the path to the virtualenv.
-        if not bare:
-            location = shorten_path(location)
-        if not location:
+        if not project.pipfile_exists:
             click.echo(
                 "No Pipfile present at project home. Consider running "
                 "{0} first to automatically generate a Pipfile for you."
                 "".format(crayons.green("`pipenv install`")),
                 err=True,
             )
-        elif not bare:
+            return
+        location = project.pipfile_location
+        # Shorten the virtual display of the path to the virtualenv.
+        if not bare:
+            location = shorten_path(location)
             click.echo(
                 "Pipfile found at {0}.\n  Considering this to be the project home."
                 "".format(crayons.green(location)),
                 err=True,
             )
-            pass
         else:
             click.echo(project.project_directory)
     else:

pipenv/project.py

@@ -54,7 +54,7 @@ def _normalized(p):
         path_str = matches and matches[0] or str(loc)
     else:
         path_str = str(loc)
-    return normalize_drive(path_str)
+    return normalize_drive(os.path.abspath(path_str))
 
 
 DEFAULT_NEWLINES = u"\n"
@@ -226,7 +226,7 @@ def name(self):
 
     @property
     def pipfile_exists(self):
-        return bool(self.pipfile_location)
+        return os.path.isfile(self.pipfile_location)
 
     @property
     def required_python_version(self):
@@ -241,11 +241,7 @@ def required_python_version(self):
 
     @property
     def project_directory(self):
-        if self.pipfile_location is not None:
-            return os.path.abspath(os.path.join(self.pipfile_location, os.pardir))
-
-        else:
-            return None
+        return os.path.abspath(os.path.join(self.pipfile_location, os.pardir))
 
     @property
     def requirements_exists(self):
@@ -259,8 +255,7 @@ def is_venv_in_project(self):
 
     @property
     def virtualenv_exists(self):
-        # TODO: Decouple project from existence of Pipfile.
-        if self.pipfile_exists and os.path.exists(self.virtualenv_location):
+        if os.path.exists(self.virtualenv_location):
             if os.name == "nt":
                 extra = ["Scripts", "activate.bat"]
             else:
@@ -478,7 +473,7 @@ def pipfile_location(self):
             try:
                 loc = pipfile.Pipfile.find(max_depth=PIPENV_MAX_DEPTH)
             except RuntimeError:
-                loc = None
+                loc = "Pipfile"
             self._pipfile_location = _normalized(loc)
         return self._pipfile_location
 
@@ -507,6 +502,8 @@ def parsed_pipfile(self):
 
     def read_pipfile(self):
         # Open the pipfile, read it into memory.
+        if not self.pipfile_exists:
+            return ""
         with io.open(self.pipfile_location) as f:
             contents = f.read()
             self._pipfile_newlines = preferred_newlines(f)
@@ -664,11 +661,6 @@ def dev_packages(self):
         """Returns a list of dev-packages, for pip-tools to consume."""
         return self._build_package_list("dev-packages")
 
-    def touch_pipfile(self):
-        """Simply touches the Pipfile, for later use."""
-        with open("Pipfile", "a"):
-            os.utime("Pipfile", None)
-
     @property
     def pipfile_is_empty(self):
         if not self.pipfile_exists:
@@ -685,8 +677,7 @@ def create_pipfile(self, python=None):
             ConfigOptionParser, make_option_group, index_group
         )
 
-        name = self.name if self.name is not None else "Pipfile"
-        config_parser = ConfigOptionParser(name=name)
+        config_parser = ConfigOptionParser(name=self.name)
         config_parser.add_option_group(make_option_group(index_group, config_parser))
         install = config_parser.option_groups[0]
         indexes = (
@@ -839,7 +830,7 @@ def write_lockfile(self, content):
 
     @property
     def pipfile_sources(self):
-        if "source" not in self.parsed_pipfile:
+        if self.pipfile_is_empty or "source" not in self.parsed_pipfile:
             return [DEFAULT_SOURCE]
         # We need to make copies of the source info so we don't
         # accidentally modify the cache. See #2100 where values are