Add missing Paste dependency. (#735)

* Add missing Paste dependency.

Otherwise Zope won't start up when installed with `pip` and the
`constraints.txt` file.

* - move Paste into an extra

* Some more coherence

with the previous example

* - the extra doesn't exist yet on 4.1.2, but will on 4.1.3 [ci skip]

* - note about changed install [ci skip]

CHANGES.rst

@@ -12,6 +12,11 @@ https://github.com/zopefoundation/Zope/blob/4.0a6/CHANGES.rst
 4.1.3 (unreleased)
 ------------------
 
+- Add ``Paste`` as ``extras_require`` dependency to pull in ``Paste`` when
+  installing with `pip` and `constraints.txt` to prevent startup errors.
+  This requires adding the ``[wsgi]`` extra in the egg specification.
+  (`#734 <https://github.com/zopefoundation/Zope/issues/734>`_)
+
 - Fix broken deprecated import when ZServer is not installed
   (`#714 <https://github.com/zopefoundation/Zope/issues/714>`_)
 

buildout.cfg

@@ -52,8 +52,7 @@ eggs = ZServer
 recipe = zc.recipe.egg
 interpreter = zopepy
 eggs =
-    Paste
-    Zope
+    Zope[wsgi]
     zodbupdate
 
 

docs/INSTALL.rst

@@ -188,8 +188,8 @@ version you find on https://zopefoundation.github.io/Zope/:
   $ python3.7 -m venv zope
   $ cd zope
   $ bin/pip install -U pip
-  $ bin/pip install Zope==4.1 \
-    -c https://zopefoundation.github.io/Zope/releases/4.1/constraints.txt
+  $ bin/pip install Zope[wsgi]==4.1.3 \
+    -c https://zopefoundation.github.io/Zope/releases/4.1.3/constraints.txt
 
 .. note::
 
@@ -203,7 +203,7 @@ more than are listed in the ``install_requires`` section of ``setup.py``):
 .. code-block:: console
 
     $ bin/pip install \
-    -r https://zopefoundation.github.io/Zope/releases/4.1/requirements-full.txt
+    -r https://zopefoundation.github.io/Zope/releases/4.1.3/requirements-full.txt
 
 If you are on Python 2 and want to use ZServer instead of WSGI , you'll have to
 install that package seperately using the version spec in constraints.txt

setup.py

@@ -132,6 +132,9 @@ def _read_file(filename):
             'sphinx_rtd_theme',
             'repoze.sphinx.autointerface',
         ],
+        'wsgi': [
+            'Paste',
+        ],
     },
     entry_points={
         'paste.app_factory': [