diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectState.java b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectState.java
index 95386afb..88f4d1f 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectState.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectState.java
@@ -87,7 +87,7 @@
   private final List<CommentLinkInfo> commentLinks;
 
   private final ProjectConfig config;
-  private final Map<String, ProjectLevelConfig> configs;
+  private final Map<ConfigKey, ProjectLevelConfig> configs;
   private final Set<AccountGroup.UUID> localOwners;
 
   /** Prolog rule state. */
@@ -227,8 +227,9 @@
   }
 
   public ProjectLevelConfig getConfig(String fileName, String ref) {
-    if (configs.containsKey(fileName)) {
-      return configs.get(fileName);
+    ConfigKey cfgKey = new ConfigKey(fileName, ref);
+    if (configs.containsKey(cfgKey)) {
+      return configs.get(cfgKey);
     }
 
     ProjectLevelConfig cfg = new ProjectLevelConfig(fileName, ref, this);
@@ -245,7 +246,7 @@
       log.warn("Failed to load " + fileName + " for " + getProject().getName(), e);
     }
 
-    configs.put(fileName, cfg);
+    configs.put(cfgKey, cfg);
     return cfg;
   }
 
@@ -504,4 +505,26 @@
     }
     return false;
   }
+
+  private static class ConfigKey {
+    final String file;
+    final String ref;
+
+    ConfigKey(String file, String ref) {
+      this.file = file;
+      this.ref = ref;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      return other instanceof ConfigKey
+          && file.equals(((ConfigKey) other).file)
+          && ref.equals(((ConfigKey) other).ref);
+    }
+
+    @Override
+    public int hashCode() {
+      return file.hashCode() * 31 + ref.hashCode();
+    }
+  }
 }