Allow configuration of a default value for a label.

This change allows a project admin or owner to define a default value
(or score) for a label. The default value is set in the project configurations
file with a 'defaultValue' key.  The defaultValue must be within the range of
valid label values.  It is an optional label setting, if not defined the
defaultValue for the label will be 0.  When a defaultValue is defined, that
value will get set in the Reply dialog by default.  A defaultValue can be set
to a score that is outside of the permissible range for a user.  In that case
the score that will get set in the Reply box will be the next closes score
to the defaultValue.

feature: Issue 2041
Change-Id: I12dece29b043e09eaab62cdcf56146a1380041bc

gerrit-server/src/test/java/com/google/gerrit/server/git/ProjectConfigTest.java

@@ -21,9 +21,11 @@ import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import com.google.common.collect.Iterables;
 import com.google.gerrit.common.data.AccessSection;
 import com.google.gerrit.common.data.ContributorAgreement;
 import com.google.gerrit.common.data.GroupReference;
+import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.reviewdb.client.AccountGroup;
@@ -47,6 +49,7 @@ import org.junit.Test;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.Map;
 
 public class ProjectConfigTest extends LocalDiskRepositoryTestCase {
   private final GroupReference developers = new GroupReference(
@@ -114,6 +117,60 @@ public class ProjectConfigTest extends LocalDiskRepositoryTestCase {
     assertFalse(push.getExclusiveGroup());
   }
 
+  @Test
+  public void testReadConfigLabelDefaultValue() throws Exception {
+    RevCommit rev = util.commit(util.tree( //
+        util.file("groups", util.blob(group(developers))), //
+        util.file("project.config", util.blob(""//
+            + "[label \"CustomLabel\"]\n" //
+            + "  value = -1 Negative\n" //
+            + "  value =  0 No Score\n" //
+            + "  value =  1 Positive\n")) //
+        ));
+
+    ProjectConfig cfg = read(rev);
+    Map<String, LabelType> labels = cfg.getLabelSections();
+    Short dv = labels.entrySet().iterator().next().getValue().getDefaultValue();
+    assertEquals(0, (int) dv);
+  }
+
+  @Test
+  public void testReadConfigLabelDefaultValueInRange() throws Exception {
+    RevCommit rev = util.commit(util.tree( //
+        util.file("groups", util.blob(group(developers))), //
+        util.file("project.config", util.blob(""//
+            + "[label \"CustomLabel\"]\n" //
+            + "  value = -1 Negative\n" //
+            + "  value =  0 No Score\n" //
+            + "  value =  1 Positive\n" //
+            + "  defaultValue = -1\n")) //
+        ));
+
+    ProjectConfig cfg = read(rev);
+    Map<String, LabelType> labels = cfg.getLabelSections();
+    Short dv = labels.entrySet().iterator().next().getValue().getDefaultValue();
+    assertEquals(-1, (int) dv);
+  }
+
+  @Test
+  public void testReadConfigLabelDefaultValueNotInRange() throws Exception {
+    RevCommit rev = util.commit(util.tree( //
+        util.file("groups", util.blob(group(developers))), //
+        util.file("project.config", util.blob(""//
+            + "[label \"CustomLabel\"]\n" //
+            + "  value = -1 Negative\n" //
+            + "  value =  0 No Score\n" //
+            + "  value =  1 Positive\n" //
+            + "  defaultValue = -2\n")) //
+        ));
+
+    ProjectConfig cfg = read(rev);
+    assertEquals(1, cfg.getValidationErrors().size());
+    assertEquals("project.config: Invalid defaultValue \"-2\" "
+        + "for label \"CustomLabel\"",
+        Iterables.getOnlyElement(cfg.getValidationErrors()).getMessage());
+  }
+
   @Test
   public void testEditConfig() throws Exception {
     RevCommit rev = util.commit(util.tree( //

gerrit-server/src/test/java/com/google/gerrit/server/schema/SchemaCreatorTest.java

@@ -129,6 +129,7 @@ public class SchemaCreatorTest {
     assertNotNull(codeReview);
     assertEquals("Code-Review", codeReview.getName());
     assertEquals("CR", codeReview.getAbbreviation());
+    assertEquals(0, codeReview.getDefaultValue());
     assertEquals("MaxWithBlock", codeReview.getFunctionName());
     assertTrue(codeReview.isCopyMinScore());
     assertValueRange(codeReview, 2, 1, 0, -1, -2);