Null-annotated Repository class and fixed related compiler errors

org.eclipse.jgit.lib.Repository class is an example of the API which
should be written with Java 8 java.util.Optional<T> type. Unfortunately
this API is already released and widely used. The good clients are
currently doing their best with checking return values for null and bad
clients do not know how bad their code is.

I've tried not to change any logic and to be as less intrusive as
possible. Most of the JGit code was well prepared to this, only few
classes needed some smaller fixes.

This change fixes all compiler errors in JGit and replaces possible
NPE's with either appropriate exceptions, avoiding multiple "Nullable
return" method calls or early returning from the method.

Because annotating getDirectory() and getFS() as Nullable would cause
lot of additional changes in JGit and EGit they are postponed.

Change-Id: Ie8369d2c9c5fac5ce83b3b1b9bc217d7b55502a3
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
index 6e3b3047fb..5f80b8103b 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
@@ -45,6 +45,7 @@ cannotBeCombined=Cannot be combined.
 cannotBeRecursiveWhenTreesAreIncluded=TreeWalk shouldn't be recursive when tree objects are included.
 cannotChangeActionOnComment=Cannot change action on comment line in git-rebase-todo file, old action: {0}, new action: {1}.
 cannotChangeToComment=Cannot change a non-comment line to a comment line.
+cannotCheckoutFromUnbornBranch=Cannot checkout from unborn branch
 cannotCheckoutOursSwitchBranch=Checking out ours/theirs is only possible when checking out index, not when switching branches.
 cannotCombineSquashWithNoff=Cannot combine --squash with --no-ff.
 cannotCombineTreeFilterWithRevFilter=Cannot combine TreeFilter {0} with RevFilter {1}.
@@ -345,6 +346,7 @@ invalidPathReservedOnWindows=Invalid path (''{0}'' is reserved on Windows): {1}
 invalidReflogRevision=Invalid reflog revision: {0}
 invalidRefName=Invalid ref name: {0}
 invalidRemote=Invalid remote: {0}
+invalidRepositoryStateNoHead=Invalid repository --- cannot read HEAD
 invalidShallowObject=invalid shallow object {0}, expected commit
 invalidStageForPath=Invalid stage {0} for path {1}
 invalidTagOption=Invalid tag option: {0}