Repository: pypa/pipenv

Issue:
Where to find environment configuration defaults
While getting started with `pipenv` and reading thorough the documentation, I came across [_Configuration With Environment Variables_](https://docs.pipenv.org/advanced/#configuration-with-environment-variables).

Unfortunately, some of the items don't list their default value, and I'm not quite sure how to find it. So while I'm initially curious if anyone could point me in the right direction, I also think it would be useful to newcomers if they were listed in the section linked above.


Discussion:
The defaults can be found in [`environments.py`](https://github.com/pypa/pipenv/blob/master/pipenv/environments.py). Indeed we should document this better, but writing those values directly in text form risks them being outdated when we update the source (and inevitably forget to update the documentation). I wonder if there is a better way to do this, maybe via `sphinx.autodoc`?

Resolving patch:
diff --git a/docs/conf.py b/docs/conf.py
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -35,11 +35,13 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['sphinx.ext.autodoc',
+extensions = [
+    'sphinx.ext.autodoc',
     'sphinx.ext.todo',
     'sphinx.ext.coverage',
     'sphinx.ext.viewcode',
-    'sphinx_click.ext']
+    'sphinx_click.ext',
+]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
@@ -119,6 +121,10 @@
 html_static_path = ['_static']
 
 
+def setup(app):
+    app.add_stylesheet('custom.css')
+
+
 # -- Options for HTMLHelp output ------------------------------------------
 
 # Output file base name for HTML help builder.
diff --git a/pipenv/environments.py b/pipenv/environments.py
--- a/pipenv/environments.py
+++ b/pipenv/environments.py
@@ -2,79 +2,212 @@
 import sys
 from appdirs import user_cache_dir
 
+
+# HACK: avoid resolver.py uses the wrong byte code files.
+# I hope I can remove this one day.
 os.environ["PYTHONDONTWRITEBYTECODE"] = "1"
 
-# Prevent invalid shebangs with Homebrew-installed Python:
+# HACK: Prevent invalid shebangs with Homebrew-installed Python:
 # https://bugs.python.org/issue22490
 os.environ.pop("__PYVENV_LAUNCHER__", None)
-# Shell compatibility mode, for mis-configured shells.
-PIPENV_SHELL_FANCY = bool(os.environ.get("PIPENV_SHELL_FANCY"))
-# Support for both Python 2 and Python 3 at the same time.
-PIPENV_PYTHON = os.environ.get("PIPENV_PYTHON")
-# Create the virtualenv in the project, instead of in WORKON_HOME.
-PIPENV_VENV_IN_PROJECT = bool(os.environ.get("PIPENV_VENV_IN_PROJECT"))
-# Overwrite all index funcitonality.
-PIPENV_TEST_INDEX = os.environ.get("PIPENV_TEST_INDEX")
-# No color mode, for unfun people.
+
+
+PIPENV_CACHE_DIR = os.environ.get("PIPENV_CACHE_DIR", user_cache_dir("pipenv"))
+"""Location for Pipenv to store it's package cache.
+
+Default is to use appdir's user cache directory.
+"""
+
 PIPENV_COLORBLIND = bool(os.environ.get("PIPENV_COLORBLIND"))
-# Disable spinner for better test and deploy logs (for the unworthy).
-PIPENV_NOSPIN = bool(os.environ.get("PIPENV_NOSPIN"))
-# Tells Pipenv how many rounds of resolving to do for Pip-Tools.
-PIPENV_MAX_ROUNDS = int(os.environ.get("PIPENV_MAX_ROUNDS", "16"))
-# Specify how many retries Pipenv should attempt for network requests.
-default_retries = "1" if "CI" in os.environ else "0"
-PIPENV_MAX_RETRIES = int(os.environ.get("PIPENV_MAX_RETRIES", default_retries))
-# Specify a custom Pipfile location.
-PIPENV_PIPFILE = os.environ.get("PIPENV_PIPFILE")
+"""If set, disable terminal colors.
+
+Some people don't like colors in their terminals, for some reason. Default is
+to show colors.
+"""
+
 # Tells Pipenv which Python to default to, when none is provided.
 PIPENV_DEFAULT_PYTHON_VERSION = os.environ.get("PIPENV_DEFAULT_PYTHON_VERSION")
-# Tells Pipenv to not load .env files.
+"""Use this Python version when creating new virtual environments by default.
+
+This can be set to a version string, e.g. ``3.6``, or a path. Default is to use
+whatever Python Pipenv is installed under (i.e. ``sys.executable``). Command
+line flags (e.g. ``--python``, ``--three``, and ``--two``) are prioritized over
+this configuration.
+"""
+
 PIPENV_DONT_LOAD_ENV = bool(os.environ.get("PIPENV_DONT_LOAD_ENV"))
-# Tell Pipenv to default to yes at all prompts.
-PIPENV_YES = bool(os.environ.get("PIPENV_YES"))
-# Tells Pipenv how many subprocesses to use when installing.
-PIPENV_MAX_SUBPROCESS = int(os.environ.get("PIPENV_MAX_SUBPROCESS", "16"))
-# User-configurable max-depth for Pipfile searching.
-# Note: +1 because of a temporary bug in Pipenv.
+"""If set, Pipenv does not load the ``.env`` file.
+
+Default is to load ``.env`` for ``run`` and ``shell`` commands.
+"""
+
+PIPENV_DONT_USE_PYENV = bool(os.environ.get("PIPENV_DONT_USE_PYENV"))
+"""If set, Pipenv does not attempt to install Python with pyenv.
+
+Default is to install Python automatically via pyenv when needed, if possible.
+"""
+
+PIPENV_DOTENV_LOCATION = os.environ.get("PIPENV_DOTENV_LOCATION")
+"""If set, Pipenv loads the ``.env`` file at the specified location.
+
+Default is to load ``.env`` from the project root, if found.
+"""
+
+PIPENV_EMULATOR = os.environ.get("PIPENV_EMULATOR", "")
+"""If set, the terminal emulator's name for ``pipenv shell`` to use.
+
+Default is to detect emulators automatically. This should be set if your
+emulator, e.g. Cmder, cannot be detected correctly.
+"""
+
+PIPENV_HIDE_EMOJIS = bool(os.environ.get("PIPENV_HIDE_EMOJIS"))
+"""Disable emojis in output.
+
+Default is to show emojis. This is automatically set on Windows.
+"""
+if os.name == "nt":
+    PIPENV_HIDE_EMOJIS = True
+
+PIPENV_IGNORE_VIRTUALENVS = bool(os.environ.get("PIPENV_IGNORE_VIRTUALENVS"))
+"""If set, Pipenv will always assign a virtual environment for this project.
+
+By default, Pipenv tries to detect whether it is run inside a virtual
+environment, and reuses it if possible. This is usually the desired behavior,
+and enables the user to use any user-built environments with Pipenv.
+"""
+
+PIPENV_INSTALL_TIMEOUT = 60 * 15
+"""Max number of seconds to wait for package installation.
+
+Defaults to 900 (15 minutes), a very long arbitrary time.
+"""
+
+# NOTE: +1 because of a temporary bug in Pipenv.
 PIPENV_MAX_DEPTH = int(os.environ.get("PIPENV_MAX_DEPTH", "3")) + 1
-# Tell Pipenv not to inherit parent directories (for development, mostly).
+"""Maximum number of directories to recursively search for a Pipfile.
+
+Default is 3. See also ``PIPENV_NO_INHERIT``.
+"""
+
+PIPENV_MAX_RETRIES = int(os.environ.get(
+    "PIPENV_MAX_RETRIES",
+    "1" if "CI" in os.environ else "0",
+))
+"""Specify how many retries Pipenv should attempt for network requests.
+
+Default is 0. Aautomatically set to 1 on CI environments for robust testing.
+"""
+
+PIPENV_MAX_ROUNDS = int(os.environ.get("PIPENV_MAX_ROUNDS", "16"))
+"""Tells Pipenv how many rounds of resolving to do for Pip-Tools.
+
+Default is 16, an arbitrary number that works most of the time.
+"""
+
+PIPENV_MAX_SUBPROCESS = int(os.environ.get("PIPENV_MAX_SUBPROCESS", "16"))
+"""How many subprocesses should Pipenv use when installing.
+
+Default is 16, an arbitrary number that seems to work.
+"""
+
 PIPENV_NO_INHERIT = "PIPENV_NO_INHERIT" in os.environ
+"""Tell Pipenv not to inherit parent directories.
+
+This is useful for deployment to avoid using the wrong current directory.
+Overwrites ``PIPENV_MAX_DEPTH``.
+"""
 if PIPENV_NO_INHERIT:
     PIPENV_MAX_DEPTH = 2
-# Tells Pipenv to use the virtualenv-provided pip instead.
-PIPENV_VIRTUALENV = None
-PIPENV_USE_SYSTEM = False
-if "PIPENV_ACTIVE" not in os.environ:
-    if "PIPENV_IGNORE_VIRTUALENVS" not in os.environ:
-        PIPENV_VIRTUALENV = os.environ.get("VIRTUAL_ENV")
-        PIPENV_USE_SYSTEM = bool(os.environ.get("VIRTUAL_ENV"))
-# Tells Pipenv to use hashing mode.
-PIPENV_USE_HASHES = True
-# Tells Pipenv to skip case-checking (slow internet connections).
-PIPENV_SKIP_VALIDATION = True
-# Tells Pipenv where to load .env from.
-PIPENV_DOTENV_LOCATION = os.environ.get("PIPENV_DOTENV_LOCATION")
-# Disable spinner on Windows.
-if os.name == "nt":
-    PIPENV_NOSPIN = True
-# Disable the spinner on Travis-Ci (and friends).
-if "CI" in os.environ:
+
+PIPENV_NOSPIN = bool(os.environ.get("PIPENV_NOSPIN"))
+"""If set, disable terminal spinner.
+
+This can make the logs cleaner. Automatically set on Windows, and in CI
+environments.
+"""
+if os.name == "nt" or "CI" in os.environ:
     PIPENV_NOSPIN = True
-PIPENV_HIDE_EMOJIS = bool(os.environ.get("PIPENV_HIDE_EMOJIS"))
-if os.name == "nt":
-    PIPENV_HIDE_EMOJIS = True
-# Tells Pipenv how long to wait for virtualenvs to be created in seconds.
+
+PIPENV_PIPFILE = os.environ.get("PIPENV_PIPFILE")
+"""If set, this specifies a custom Pipfile location.
+
+When running pipenv from a location other than the same directory where the
+Pipfile is located, instruct pipenv to find the Pipfile in the location
+specified by this environment variable.
+
+Default is to find Pipfile automatically in the current and parent directories.
+See also ``PIPENV_MAX_DEPTH``.
+"""
+
+PIPENV_PYPI_MIRROR = os.environ.get("PIPENV_PYPI_MIRROR")
+"""If set, tells pipenv to override PyPI index urls with a mirror.
+
+Default is to not mirror PyPI, i.e. use the real one, pypi.org. The
+``--pypi-mirror`` command line flag overwrites this.
+"""
+
+PIPENV_SHELL = os.environ.get("PIPENV_SHELL")
+"""An absolute path to the preferred shell for ``pipenv shell``.
+
+Default is to detect automatically what shell is currently in use.
+"""
+# Hack because PIPENV_SHELL is actually something else. Internally this
+# variable is called PIPENV_SHELL_EXPLICIT instead.
+PIPENV_SHELL_EXPLICIT = PIPENV_SHELL
+del PIPENV_SHELL
+
+PIPENV_SHELL_FANCY = bool(os.environ.get("PIPENV_SHELL_FANCY"))
+"""If set, always use fancy mode when invoking ``pipenv shell``.
+
+Default is to use the compatibility shell if possible.
+"""
+
 PIPENV_TIMEOUT = int(os.environ.get("PIPENV_TIMEOUT", 120))
-PIPENV_INSTALL_TIMEOUT = 60 * 15
-PIPENV_DONT_USE_PYENV = os.environ.get("PIPENV_DONT_USE_PYENV")
+"""Max number of seconds Pipenv will wait for virtualenv creation to complete.
+
+Default is 120 seconds, an arbitrary number that seems to work.
+"""
+
+PIPENV_VENV_IN_PROJECT = bool(os.environ.get("PIPENV_VENV_IN_PROJECT"))
+"""If set, creates ``.venv`` in your project directory.
+
+Default is to create new virtual environments in a global location.
+"""
+
+PIPENV_YES = bool(os.environ.get("PIPENV_YES"))
+"""If set, Pipenv automatically assumes "yes" at all prompts.
+
+Default is to prompt the user for an answer if the current command line session
+if interactive.
+"""
+
+
+# Internal, support running in a different Python from sys.executable.
+PIPENV_PYTHON = os.environ.get("PIPENV_PYTHON")
+
+# Internal, overwrite all index funcitonality.
+PIPENV_TEST_INDEX = os.environ.get("PIPENV_TEST_INDEX")
+
+# Internal, tells Pipenv about the surrounding environment.
+PIPENV_USE_SYSTEM = False
+PIPENV_VIRTUALENV = None
+if "PIPENV_ACTIVE" not in os.environ and not PIPENV_IGNORE_VIRTUALENVS:
+    PIPENV_VIRTUALENV = os.environ.get("VIRTUAL_ENV")
+    PIPENV_USE_SYSTEM = bool(PIPENV_VIRTUALENV)
+
+# Internal, tells Pipenv to skip case-checking (slow internet connections).
+# This is currently always set to True for performance reasons.
+PIPENV_SKIP_VALIDATION = True
+
+# Internal, the default shell to use if shell detection fails.
+PIPENV_SHELL = os.environ.get("SHELL") or os.environ.get("PYENV_SHELL")
+
+# Internal, to tell if pyenv is installed.
 PYENV_ROOT = os.environ.get("PYENV_ROOT", os.path.expanduser("~/.pyenv"))
-PYENV_INSTALLED = bool(os.environ.get("PYENV_SHELL")) or bool(
-    os.environ.get("PYENV_ROOT")
+PYENV_INSTALLED = (
+    bool(os.environ.get("PYENV_SHELL")) or
+    bool(os.environ.get("PYENV_ROOT"))
 )
+
+# Internal, to tell whether the command line session is interactive.
 SESSION_IS_INTERACTIVE = bool(os.isatty(sys.stdout.fileno()))
-PIPENV_SHELL_EXPLICIT = os.environ.get("PIPENV_SHELL")
-PIPENV_SHELL = os.environ.get("SHELL") or os.environ.get("PYENV_SHELL")
-PIPENV_EMULATOR = os.environ.get("PIPENV_EMULATOR")
-PIPENV_CACHE_DIR = os.environ.get("PIPENV_CACHE_DIR", user_cache_dir("pipenv"))
-# Tells pipenv to override PyPI index urls with a mirror.
-PIPENV_PYPI_MIRROR = os.environ.get("PIPENV_PYPI_MIRROR")
diff --git a/pipenv/shells.py b/pipenv/shells.py
--- a/pipenv/shells.py
+++ b/pipenv/shells.py
@@ -210,6 +210,6 @@ def _detect_emulator():
 
 
 def choose_shell():
-    emulator = PIPENV_EMULATOR or _detect_emulator()
+    emulator = PIPENV_EMULATOR.lower() or _detect_emulator()
     type_, command = detect_info()
     return SHELL_LOOKUP[type_][emulator](command)


Test patch: