Use sphinx warning-is-error

Sphix 1.5 (I9e7261c4124b71eeb6bddd9e21747b61bbdc16fa) includes
"warning-is-error" which supersedes pbr's warnerrors.  Enable this and
fix up the resulting failures

 - trailing lines for lists in element_deps directive
 - missing README's that are linked
 - syntax error and highlighting in building instructions

Change-Id: I6549551b4a9bf47076c9811a7a38a666cbea2a50

.gitignore

@@ -19,3 +19,5 @@ build
 AUTHORS
 ChangeLog
 bin/diskimage_builder
+*.bak
+*.orig

diskimage_builder/elements/debian-minimal/README.rst

@@ -13,7 +13,6 @@ There are two ways to configure apt-sources:
 
    * ``DIB_DISTRIBUTION_MIRROR``: the mirror to use (default:
      `<http://ftp.us.debian.org/debian>`__)
-
    * ``DIB_DEBIAN_COMPONENTS``: (default: ``main``) a comma
      separated list of components. For Debian this can be
      e.g. ``main,contrib,non-free``.

diskimage_builder/elements/debian/README.rst

@@ -1,8 +1,9 @@
 ======
 debian
 ======
-Create an image based on Debian. We default to unstable but DIB_RELEASE
-is mapped to any series of Debian.
+
+Create an image based on Debian. We default to unstable but
+``DIB_RELEASE`` is mapped to any series of Debian.
 
 Note that the default Debian series is `unstable`, and the default
 mirrors for Debian can be problematic for `unstable`. Because apt does

diskimage_builder/elements/dib-run-parts/README.rst

@@ -0,0 +1,7 @@
+=============
+dib-run-parts
+=============
+
+Install ``dib-run-parts`` into the chroot environment
+
+

diskimage_builder/elements/ubuntu-signed/README.rst

@@ -0,0 +1,9 @@
+=============
+ubuntu-signed
+=============
+
+The ``ubuntu-signed`` element installs ``linux-signed-image-generic``
+that provides signed kernel that can be used for deploy in UEFI secure
+boot mode.
+
+.. element_deps::

doc/lib/element_deps.py

@@ -29,13 +29,14 @@ import os
 all_elements = _find_all_elements(get_path("elements"))
 
 
-def append_dependency_list(lines, title, element, deps):
-    if not deps:
-        return
+def make_dep_list(title, deps):
+    lines = []
     lines.append(title)
     lines.append("+" * len(title))
     for dep in deps:
-        lines.append("* :doc:`../%s/README`\n" % dep)
+        lines.append("* :doc:`../%s/README`" % dep)
+    lines.append('')  # careful to end with a blank line
+    return lines
 
 
 class ElementDepsDirective(Directive):
@@ -56,11 +57,13 @@ class ElementDepsDirective(Directive):
         # This should not fail -- sphinx would be finding an element
         # that dib doesn't know about?
         element = all_elements[element_name]
-
-        append_dependency_list(lines, "Uses", element, element.depends)
-        append_dependency_list(lines, "Used by", element, element.r_depends)
+        if element.depends:
+            lines.extend(make_dep_list("Uses", element.depends))
+        if element.r_depends:
+            lines.extend(make_dep_list("Used by", element.r_depends))
 
         self.state_machine.insert_input(lines, source)
+
         return []
 
 

doc/source/user_guide/building_an_image.rst

@@ -238,7 +238,8 @@ size
 
 Example:
 
-::
+.. code-block:: yaml
+
    - partitioning:
       base: image0
       label: mbr

setup.cfg

@@ -19,6 +19,7 @@ classifier =
 all_files = 1
 build-dir = doc/build
 source-dir = doc/source
+warning-is-error = 1
 
 [files]
 packages =
@@ -36,10 +37,6 @@ keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = diskimage_builder/locale/diskimage_builder.pot
 
-[pbr]
-# TODO(jaegerandi): Set to True once pbr 1.11.0 is out.
-warnerrors = False
-
 [update_catalog]
 domain = diskimage_builder
 output_dir = diskimage_builder/locale