Pulling doChildrenContextMenu up from AbstractProject into Job, since the latter already defines permalinks.

Moved configuration of keepDependencies into AbstractProject/configure-common.jelly, since it is not a property of Fingerprinter.

Undeprecating Job.getBuild, since this is the only way to look up a build by ID if you are unsure what kind of Job it is.

Null check the 'properties' element of the json message before attempting to 'rebuild' the 'DescribableList'

Cf.: https://github.com/jenkinsci/subversion-plugin/pull/83

java.lang.NullPointerException
	at hudson.model.Job.getBuildDir(Job.java:790)
	at hudson.model.Run.getRootDir(Run.java:993)
	at hudson.model.Run.getLogFile(Run.java:1306)
	at hudson.model.Run.execute(Run.java:1664)
	at hudson.maven.MavenBuild.access$900(MavenBuild.java:94)
	at hudson.maven.MavenBuild$ProxyImpl2.close(MavenBuild.java:636)
	at hudson.maven.AbstractMavenBuilder.end(AbstractMavenBuilder.java:106)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:839)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:523)
	at hudson.model.Run.execute(Run.java:1688)
	at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:519)
	at hudson.model.ResourceController.execute(ResourceController.java:88)
	at hudson.model.Executor.run(Executor.java:231)
java.lang.NullPointerException
	at hudson.model.BuildStepListener.all(BuildStepListener.java:31)
	at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:739)
	at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:714)
	at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.cleanUp(MavenModuleSetBuild.java:1054)
	at hudson.model.Run.execute(Run.java:1733)
	at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:519)
	at hudson.model.ResourceController.execute(ResourceController.java:88)
	at hudson.model.Executor.run(Executor.java:231)

[FIX JENKINS-21303] There is a NPE here that can and does happen for real when an aggresive slave retention strategy interacts with post build triggers that want to do token macro expansion

unbuildable project.

Added a new overloaded version that works on a project.

Updated CoreEnvironmentContributor accordingly.

Loading the last 3 successful builds may be very expensive in certain rare, but possible situations (all newer builds failed, only some very old builds were successful).
Go only up to 6 build into the past for calculating the estimated duration.
Also take failed builds into account, if we don't find any successful ones.

- Fixes a regression in core where the display name clear on copy was triggering a save
- More than one way to do this, could also have used the marker interface approach
  This route seems slightly less fragile, though people could still add ItemListeners
  with order == -Double.MAX_VALUE which would then introduce intdeterminism.
  A marker interface would remove that indeterminism as the onCopyComplete method would
  be only called on the Job as the last method... but it could be hard to
  ensure that all ItemGroupMixin's respect the calling of onCopyComplete contract
  hence this approach seems better to me for that reason

Report 100 recent builds in the JSON API, including in-progress builds.

Not reporting all the builds since this would nullify the lazy loading
effect. Will introduce a pagenation API that supports retrieval.

Based on comments from Jesse, revising the fix.

I'm now putting permlinks inside the builds/ directory to avoid the computing hassle involved in the split $JENKINS_HOME.

What we historically had in $JENKINS_HOME/jobs/JOB/lastSuccessfulBuild is also now subsumed by this feature. I initially attempted to create these permalinks in the buidl root directory, but turns out those symlinks aren't the same name as the ID of permalinks, so it doesn't mesh well.

And finally, a test!

Remember the permalink target as symlink (or simple text file) so that
looking that up doesn't cause the walk of the build history.
I think this is more in line with our general preference of making
$JENKINS_HOME useful (than trying to persist cache into a blackbox.)

Having a general purpose in-memory cache could be useful, so I'll see if
I can add that, too, in a way that allows someone to plug different
backend.

This is done by introducing a new base type 'BuildDiscarder' that's
extensible. Plugins can implement their own logics.

- save() is not strictly necessary here. config.xml might be saved later or not - doesn't really matter
- this else branch should only be entered when migrating from very old Hudson instances

We are replacing it by the ConfidentialStore class and the
ConfidentialKey class, which provides purpose-specific confidential
information that are separated from each other.

In this way, not all eggs are in one basket, and in case of a
compromise, the impact will contained.

Also replaced several insecure use of digest(secret|messsage) or
digest(message|secret) by HMAC.

This is a signature breaking change, but it's critical in avoiding
unnecessary record load operations.
To my limited repository search, I couldn't find any use in a plugin
where RunList is casted to ArrayList, so hopefully this would be safe
enough.

overridden a number of Job methods in AbstractProject to avoid the slow path (of loading everything)