cover more edge cases: - if there is already some git information, but there was no actual checkout before - if last build data is not set - if the list of all revisions can not be received - if the revision of the last build could not received - if the revision can not be found in the list of all revisions - must be branch switch.

Author: hajoeichler

src/main/java/hudson/plugins/git/util/DefaultBuildChooser.java

@@ -9,13 +9,15 @@
 import hudson.plugins.git.IGitAPI;
 import hudson.plugins.git.Revision;
 import org.kohsuke.stapler.DataBoundConstructor;
-import org.eclipse.jgit.lib.ObjectId;
+import org.spearce.jgit.lib.ObjectId;
 
 import java.io.IOException;
 import java.text.MessageFormat;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Set;
 
 import static java.util.Collections.emptyList;
@@ -92,23 +94,26 @@ public Collection<Revision> getCandidateRevisions(boolean isPollCall, String sin
             verbose(listener, "Found a new commit {0} to be built on {1}", sha1, singleBranch);
 
             // calculate the revisions that are new compared to the last build
-            List<ObjectId> allRevs = git.revListAll(); // index 0 contains the newest revision
-            Revision lastBuiltRev = data.getLastBuiltRevision();
-            int indexOfLastBuildRev = allRevs.indexOf(lastBuiltRev.getSha1());
-            List<ObjectId> newRevisionsSinceLastBuild = allRevs.subList(0, indexOfLastBuildRev);
-
-            // translate list of ObjectIds into list of Revisions
             List<Revision> candidateRevs = new ArrayList<Revision>();
-            for (ObjectId objectId : newRevisionsSinceLastBuild) {
-                Revision revision = new Revision(objectId);
-                revision.getBranches().add(new Branch(singleBranch, sha1));
-                candidateRevs.add(revision);
+            List<ObjectId> allRevs = git.revListAll(); // index 0 contains the newest revision
+            if (data != null && allRevs != null) {
+                Revision lastBuiltRev = data.getLastBuiltRevision();
+                if (lastBuiltRev == null) {
+                    return Collections.singletonList(objectId2Revision(singleBranch, sha1));
+                }
+                int indexOfLastBuildRev = allRevs.indexOf(lastBuiltRev.getSha1());
+                if (indexOfLastBuildRev == -1) {
+                    // mhmmm ... can happen when branches are switched.
+                    return Collections.singletonList(objectId2Revision(singleBranch, sha1));
+                }
+                List<ObjectId> newRevisionsSinceLastBuild = allRevs.subList(0, indexOfLastBuildRev);
+                // translate list of ObjectIds into list of Revisions
+                for (ObjectId objectId : newRevisionsSinceLastBuild) {
+                    candidateRevs.add(objectId2Revision(singleBranch, objectId));
+                }
             }
-            // fallback to return given sha1 if the list of candidate revisions is empty
             if (candidateRevs.isEmpty()) {
-                Revision revision = new Revision(sha1);
-                revision.getBranches().add(new Branch(singleBranch, sha1));
-                return Collections.singletonList(revision);
+                return Collections.singletonList(objectId2Revision(singleBranch, sha1));
             }
             return candidateRevs;
         } catch (GitException e) {
@@ -118,6 +123,12 @@ public Collection<Revision> getCandidateRevisions(boolean isPollCall, String sin
         }
     }
 
+    private Revision objectId2Revision(String singleBranch, ObjectId sha1) {
+        Revision revision = new Revision(sha1);
+        revision.getBranches().add(new Branch(singleBranch, sha1));
+        return revision;
+    }
+
     /**
      * In order to determine which Revisions to build.
      *