Assume status:open if the query isn't executable

Rather than throwing back an obtuse error about not being able to
execute a query string, add in the status:open and retry to plan the
query with the rewriter.  It should succeed this time and give us a
data source that can actually evaluate.  We assume status:open because
uses are primarily interested in the open changes when they enter a
query, and the set that is open is smaller than the set that is
closed.  Users can also pretty quickly realize we are only showing
them open changes and modify their query if they needed to search
closed ones.

Change-Id: Ieaf78bde3201767eaeb973c015785413597e409a
Signed-off-by: Shawn O. Pearce <sop@google.com>

2 files changed, 15 insertions, 6 deletions

diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/ChangeListServiceImpl.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/ChangeListServiceImpl.java
index 22f5963057..c01d65ed3f 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/ChangeListServiceImpl.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/ChangeListServiceImpl.java
@@ -156,12 +156,17 @@ public class ChangeListServiceImpl extends BaseServiceImplementation implements
           builder.limit(limit), //
           visibleToMe //
           );
-      q = queryRewriter.get().rewrite(q);
-      if (q instanceof ChangeDataSource) {
-        ChangeDataSource ds = (ChangeDataSource) q;
+
+      ChangeQueryRewriter rewriter = queryRewriter.get();
+      Predicate<ChangeData> s = rewriter.rewrite(q);
+      if (!(s instanceof ChangeDataSource)) {
+        s = rewriter.rewrite(Predicate.and(builder.status_open(), q));
+      }
+
+      if (s instanceof ChangeDataSource) {
         ArrayList<Change> r = new ArrayList();
         HashSet<Change.Id> want = new HashSet<Change.Id>();
-        for (ChangeData d : ds.read()) {
+        for (ChangeData d : ((ChangeDataSource) s).read()) {
           if (d.hasChange()) {
             // Checking visibleToMe here should be unnecessary, the
             // query should have already performed it.  But we don't
@@ -190,7 +195,7 @@ public class ChangeListServiceImpl extends BaseServiceImplementation implements
         Collections.sort(r, cmp);
         return new ListResultSet<Change>(r);
       } else {
-        throw new InvalidQueryException("Not Supported", q.toString());
+        throw new InvalidQueryException("Not Supported", s.toString());
       }
     } catch (QueryParseException e) {
       throw new InvalidQueryException(e.getMessage(), query);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index be89685e35..ef48772710 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -136,7 +136,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   @Operator
   public Predicate<ChangeData> status(String statusName) {
     if ("open".equals(statusName)) {
-      return ChangeStatusPredicate.open(dbProvider);
+      return status_open();
 
     } else if ("closed".equals(statusName)) {
       return ChangeStatusPredicate.closed(dbProvider);
@@ -149,6 +149,10 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
     }
   }
 
+  public Predicate<ChangeData> status_open() {
+    return ChangeStatusPredicate.open(dbProvider);
+  }
+
   @Operator
   public Predicate<ChangeData> has(String value) {
     if ("star".equalsIgnoreCase(value)) {