Properly support html_show_sphinx (#206)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

Author: picnixz

alabaster/__init__.py

@@ -15,6 +15,16 @@ def get_path():
 def update_context(app, pagename, templatename, context, doctree):
     context["alabaster_version"] = __version__
 
+    # Convert 'show_powered_by' in the theme options to
+    # the preferred option, html_show_sphinx.
+    html_theme_options = app.config.html_theme_options
+    if "show_powered_by" in html_theme_options:
+        show_powered_by = html_theme_options["show_powered_by"]
+        if isinstance(show_powered_by, str):
+            context["show_sphinx"] = show_powered_by.lower() == "true"
+        else:
+            context["show_sphinx"] = bool(show_powered_by)  # to allow int values
+
 
 def setup(app):
     app.require_sphinx("3.4")

alabaster/layout.html

@@ -87,13 +87,13 @@
 {%- block footer %}
     <div class="footer">
       {% if show_copyright %}&copy;{{ copyright }}.{% endif %}
-      {% if theme_show_powered_by|lower == 'true' %}
+      {% if show_sphinx %}
       {% if show_copyright %}|{% endif %}
       Powered by <a href="http://sphinx-doc.org/">Sphinx {{ sphinx_version }}</a>
       &amp; <a href="https://github.com/sphinx-doc/alabaster">Alabaster {{ alabaster_version }}</a>
       {% endif %}
       {%- if show_source and has_source and sourcename %}
-      {% if show_copyright or theme_show_powered_by %}|{% endif %}
+      {% if show_copyright or show_sphinx %}|{% endif %}
       <a href="{{ pathto('_sources/' + sourcename, true)|e }}"
           rel="nofollow">{{ _('Page source') }}</a>
       {%- endif %}

docs/customization.rst

@@ -191,6 +191,10 @@ same.
 * ``show_powered_by``: Boolean controlling display of the ``Powered by
   Sphinx N.N.N. & Alabaster M.M.M`` section of the footer. When ``true``, is
   displayed next to the copyright information; when ``false``, is hidden.
+
+  .. deprecated:: 0.17.14
+     Set ``html_show_sphinx`` to ``True`` or ``False`` in ``conf.py`` instead.
+
 * ``show_relbars``: ``true`` or ``false`` - used to display *next* and
   *previous* links above and below the main page content. If you only want to
   display one, this setting can be further overridden through the