Make default search query more useful

Preserve the existing short-circuit behavior for change IDs. OR
together a laundry list of potentially useful predicates in the
default case.

We use the new projects operator for prefix searching on projects,
rather than the hand-rolled substring search previously only found in
this method.

Change-Id: I21bba55e5ff79cd5daa40dd4076f829399164244

gerrit-server/src/test/java/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java

@@ -111,6 +111,9 @@ public abstract class AbstractQueryChangesTest {
     schemaCreator.create(db);
     userId = accountManager.authenticate(AuthRequest.forUser("user"))
         .getAccountId();
+    Account userAccount = db.accounts().get(userId);
+    userAccount.setPreferredEmail("user@example.com");
+    db.accounts().update(ImmutableList.of(userAccount));
     user = userFactory.create(userId);
 
     requestContext.setContext(new RequestContext() {
@@ -805,6 +808,51 @@ public abstract class AbstractQueryChangesTest {
     assertResultEquals(change1, results.get(1));
   }
 
+  @Test
+  public void byDefault() throws Exception {
+    TestRepository<InMemoryRepository> repo = createProject("repo");
+
+    Change change1 = newChange(repo, null, null, null, null).insert();
+
+    RevCommit commit2 = repo.parseBody(
+        repo.commit().message("foosubject").create());
+    Change change2 = newChange(repo, commit2, null, null, null).insert();
+
+    RevCommit commit3 = repo.parseBody(
+        repo.commit()
+        .add("Foo.java", "foo contents")
+        .create());
+    Change change3 = newChange(repo, commit3, null, null, null).insert();
+
+    ChangeInserter ins4 = newChange(repo, null, null, null, null);
+    Change change4 = ins4.insert();
+    ReviewInput ri4 = new ReviewInput();
+    ri4.message = "toplevel";
+    ri4.labels = ImmutableMap.<String, Short> of("Code-Review", (short) 1);
+    postReview.apply(new RevisionResource(
+        changes.parse(change4.getId()), ins4.getPatchSet()), ri4);
+
+    ChangeInserter ins5 = newChange(repo, null, null, null, null);
+    Change change5 = ins5.getChange();
+    change5.setTopic("feature5");
+    ins5.insert();
+
+    Change change6 = newChange(repo, null, null, null, "branch6").insert();
+
+    assertResultEquals(change1,
+        queryOne(Integer.toString(change1.getId().get())));
+    assertResultEquals(change2, queryOne("foosubject"));
+    assertResultEquals(change3, queryOne("Foo.java"));
+    assertResultEquals(change4, queryOne("Code-Review+1"));
+    assertResultEquals(change4, queryOne("toplevel"));
+    assertResultEquals(change5, queryOne("feature5"));
+    assertResultEquals(change6, queryOne("branch6"));
+    assertResultEquals(change6, queryOne("refs/heads/branch6"));
+
+    assertEquals(6, query("user@example.com").size());
+    assertEquals(6, query("repo").size());
+  }
+
   protected ChangeInserter newChange(
       TestRepository<InMemoryRepository> repo,
       @Nullable RevCommit commit, @Nullable String key, @Nullable Integer owner,

gerrit-server/src/test/java/com/google/gerrit/server/query/change/LuceneQueryChangesV7Test.java

@@ -49,6 +49,11 @@ public class LuceneQueryChangesV7Test extends AbstractQueryChangesTest {
   @Override
   @Test
   public void byProjectPrefix() {}
+
+  @Ignore
+  @Override
+  @Test
+  public void byDefault() {}
   // End tests for features not supported in V7.
 
   @Test