Performs a project name substring search.

Search for changes whose project name contains query text as
substring using no operator for that.
E.g. Searching for just "gerrit is:open" will try to match
a project name by "gerrit" as substring and return all open
changes for this (or these) project.

Documentation/user-search.txt

@@ -46,7 +46,12 @@ Search Operators
 
 Operators act as restrictions on the search.  As more operators
 are added to the same query string, they further restrict the
-returned results.
+returned results. Search can also be performed by typing only a
+text with no operator. It will try to match a project name by
+substring.
+
+E.g. Searching for just "gerrit is:starred" will try to match a
+project name by "gerrit" as substring.
 
 [[age]]
 age:'AGE'::
@@ -87,7 +92,7 @@ Changes where 'SHA1' is one of the patch sets of the change.
 [[project]]
 project:'PROJECT'::
 +
-Changes occuring in 'PROJECT'.  If 'PROJECT' starts with `^` it
+Changes occuring in 'PROJECT'. If 'PROJECT' starts with `^` it
 matches project names by regular expression.
 
 [[branch]]

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -484,6 +484,28 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
       return label(query);
 
     } else {
+      // Try to match a project name by substring query.
+      final List<ProjectPredicate> predicate =
+          new ArrayList<ProjectPredicate>();
+      try {
+        for (final Project p : args.dbProvider.get().projects().all()) {
+          if (p.getName().toLowerCase().contains(query.toLowerCase())) {
+            predicate.add(new ProjectPredicate(args.dbProvider, p.getName()));
+          }
+        }
+
+        // If two or more projects contains "query" as substring create an
+        // OrPredicate holding predicates for all these projects, otherwise if
+        // only one contains that, return only that one predicate by itself.
+        if (predicate.size() == 1) {
+          return predicate.get(0);
+        } else if (predicate.size() > 1) {
+          return Predicate.or(predicate);
+        }
+      } catch (OrmException e) {
+        throw error("Cannot lookup project.", e);
+      }
+
       throw error("Unsupported query:" + query);
     }
   }