Document problems with plugin and provision env (refs #2469) (#2511)

Author: ziima

Diff for: docs/changelog/2469.doc.rst

@@ -0,0 +1 @@
+Documented problems with plugin and provision env - by :user:`ziima`.

Diff for: docs/config.rst

@@ -76,6 +76,11 @@ Global settings are defined under the ``tox`` section as:
     When tox is invoked with the ``--no-provision`` flag,
     the provision won't be attempted, tox will fail instead.
 
+    .. warning::
+
+      The new virtual environment will only contain dependencies specified by the :conf:`requires` keyword.
+      Any plugin used by the `tox` executable and not specified in `requires` explicitely won't be used for subsequent tasks.
+
 .. conf:: toxworkdir ^ PATH ^ {toxinidir}/.tox
 
    Directory for tox to generate its environments into, will be created if it does not exist.

Diff for: docs/plugins.rst

@@ -72,6 +72,11 @@ and locations of all installed plugins::
     registered plugins:
         tox-travis-0.10 at /home/ob/.virtualenvs/tmp/lib/python3.6/site-packages/tox_travis/hooks.py
 
+.. warning::
+
+    If the `tox.ini` used specifies :conf:`minversion` or :conf:`requires` options then registered plugins may not have any effect.
+    See :conf:`provision_tox_env` for details.
+
 
 Creating a plugin
 -----------------