Adds support for Disable GitHub Multibranch Status

Jenkins2 GitHub scms default to automatically sending updates on build
status to github for pull requests.  The plugin this enables allows
control of this by enabling or disabling the feature via an SCM trait,
allowing you to either no notify at all or manually notify via other
means.

Change-Id: I4f5629c3ee8031d41054e3be5e853201d8f0fed6
Signed-off-by: sbussetti <steve.bussetti@gmail.com>

.gitignore

@@ -3,6 +3,8 @@
 *.eggs
 *.egg-info
 *.pyc
+*.sw[a-z]
+.python-version
 .test
 .testrepository
 .tox

doc/source/conf.py

@@ -255,4 +255,5 @@ texinfo_documents = [
 # texinfo_show_urls = 'footnote'
 
 extlinks = {'jenkins-wiki': ('https://wiki.jenkins.io/display/JENKINS/%s',
-                             None)}
+                             None),
+            'jenkins-plugins': ('https://plugins.jenkins.io/%s', None)}

jenkins_jobs/modules/project_multibranch.py

@@ -785,6 +785,10 @@ def github_scm(xml_parent, data):
         * **depth** (`int`) - Set shallow clone depth (default 1)
         * **do-not-fetch-tags** (`bool`) - Perform a clone without tags
             (default false)
+        * **disable-pr-notifications** (`bool`) - Disable default github status
+            notifications on pull requests (default false) (Requires the
+            :jenkins-plugins:`GitHub Branch Source Plugin
+            <disable-github-multibranch-status>`.)
         * **submodule** (`dict`)
             * **disable** (`bool`) - By disabling support for submodules you
               can still keep using basic git plugin functionality and just have
@@ -953,6 +957,18 @@ def github_scm(xml_parent, data):
     # - use-author
     git_extensions(traits, data)
 
+    # github-only extensions
+    disable_github_status_path_dscore = (
+        'com.adobe.jenkins.disable__github__multibranch__status')
+    if data.get('disable-pr-notifications', False):
+        XML.SubElement(
+            traits, ''.join([
+                disable_github_status_path_dscore, '.DisableStatusUpdateTrait'
+            ]), {
+                'plugin': 'disable-github-multibranch-status'
+            }
+        )
+
 
 def build_strategies(xml_parent, data):
     """Configure Basic Branch Build Strategies.

tests/multibranch/fixtures/scm_github_full.xml

@@ -90,6 +90,7 @@
             <jenkins.plugins.git.traits.AuthorInChangelogTrait>
               <extension class="hudson.plugins.git.extensions.impl.AuthorInChangelog"/>
             </jenkins.plugins.git.traits.AuthorInChangelogTrait>
+            <com.adobe.jenkins.disable__github__multibranch__status.DisableStatusUpdateTrait plugin="disable-github-multibranch-status"/>
           </traits>
         </source>
         <buildStrategies>

tests/multibranch/fixtures/scm_github_full.yaml

@@ -44,6 +44,7 @@ scm:
         shallow-clone: true
         depth: 3
         do-not-fetch-tags: true
+        disable-pr-notifications: true
         submodule:
             disable: false
             recursive: true