Index: lucene/test-framework/src/java/org/apache/lucene/codecs/asserting/AssertingPostingsFormat.java
===================================================================
--- lucene/test-framework/src/java/org/apache/lucene/codecs/asserting/AssertingPostingsFormat.java	(revision 1364739)
+++ lucene/test-framework/src/java/org/apache/lucene/codecs/asserting/AssertingPostingsFormat.java	(working copy)
@@ -18,16 +18,23 @@
  */
 
 import java.io.IOException;
+import java.util.Comparator;
 
 import org.apache.lucene.codecs.FieldsConsumer;
 import org.apache.lucene.codecs.FieldsProducer;
+import org.apache.lucene.codecs.PostingsConsumer;
 import org.apache.lucene.codecs.PostingsFormat;
+import org.apache.lucene.codecs.TermStats;
+import org.apache.lucene.codecs.TermsConsumer;
 import org.apache.lucene.codecs.lucene40.Lucene40PostingsFormat;
 import org.apache.lucene.index.AssertingAtomicReader;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.FieldInfo.IndexOptions;
 import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.SegmentReadState;
 import org.apache.lucene.index.SegmentWriteState;
 import org.apache.lucene.index.Terms;
+import org.apache.lucene.util.BytesRef;
 
 /**
  * Just like {@link Lucene40PostingsFormat} but with additional asserts.
@@ -39,10 +46,9 @@
     super("Asserting");
   }
   
-  // TODO: we could add some useful checks here?
   @Override
   public FieldsConsumer fieldsConsumer(SegmentWriteState state) throws IOException {
-    return in.fieldsConsumer(state);
+    return new AssertingFieldsConsumer(in.fieldsConsumer(state));
   }
 
   @Override
@@ -85,4 +91,82 @@
       return in.getUniqueTermCount();
     }
   }
+  
+  static class AssertingFieldsConsumer extends FieldsConsumer {
+    private final FieldsConsumer in;
+    
+    AssertingFieldsConsumer(FieldsConsumer in) {
+      this.in = in;
+    }
+    
+    @Override
+    public TermsConsumer addField(FieldInfo field) throws IOException {
+      TermsConsumer consumer = in.addField(field);
+      assert consumer != null;
+      return new AssertingTermsConsumer(consumer, field);
+    }
+
+    @Override
+    public void close() throws IOException {
+      in.close();
+    }
+  }
+  
+  static enum TermsConsumerState { INITIAL, START, FINISHED };
+  static class AssertingTermsConsumer extends TermsConsumer {
+    private final TermsConsumer in;
+    private final FieldInfo fieldInfo;
+    private BytesRef lastTerm = null;
+    private TermsConsumerState state = TermsConsumerState.INITIAL;
+    
+    AssertingTermsConsumer(TermsConsumer in, FieldInfo fieldInfo) {
+      this.in = in;
+      this.fieldInfo = fieldInfo;
+    }
+    
+    // TODO: AssertingPostingsConsumer
+    @Override
+    public PostingsConsumer startTerm(BytesRef text) throws IOException {
+      // TODO: assert that if state == START (no finishTerm called), that no actual docs were fed.
+      // TODO: this makes the api really confusing! we should try to clean this up!
+      assert state == TermsConsumerState.INITIAL || state == TermsConsumerState.START;
+      state = TermsConsumerState.START;
+      assert lastTerm == null || in.getComparator().compare(text, lastTerm) > 0;
+      lastTerm = BytesRef.deepCopyOf(text);
+      return in.startTerm(text);
+    }
+
+    @Override
+    public void finishTerm(BytesRef text, TermStats stats) throws IOException {
+      assert state == TermsConsumerState.START;
+      state = TermsConsumerState.INITIAL;
+      assert text.equals(lastTerm);
+      assert stats.docFreq > 0; // otherwise, this method should not be called.
+      if (fieldInfo.getIndexOptions() == IndexOptions.DOCS_ONLY) {
+        assert stats.totalTermFreq == -1;
+      }
+      in.finishTerm(text, stats);
+    }
+
+    @Override
+    public void finish(long sumTotalTermFreq, long sumDocFreq, int docCount) throws IOException {
+      // TODO: assert that if state == START (no finishTerm called), that no actual docs were fed.
+      // TODO: this makes the api really confusing! we should try to clean this up!
+      assert state == TermsConsumerState.INITIAL || state == TermsConsumerState.START;
+      state = TermsConsumerState.FINISHED;
+      assert docCount >= 0;
+      assert sumDocFreq >= docCount;
+      if (fieldInfo.getIndexOptions() == IndexOptions.DOCS_ONLY) {
+        assert sumTotalTermFreq == -1;
+      } else {
+        assert sumTotalTermFreq >= sumDocFreq;        
+      }
+      in.finish(sumTotalTermFreq, sumDocFreq, docCount);
+    }
+
+    @Override
+    public Comparator<BytesRef> getComparator() throws IOException {
+      return in.getComparator();
+    }
+  }
 }
Index: lucene/core/src/test/org/apache/lucene/index/TestPostingsFormat.java
===================================================================
--- lucene/core/src/test/org/apache/lucene/index/TestPostingsFormat.java	(revision 1364739)
+++ lucene/core/src/test/org/apache/lucene/index/TestPostingsFormat.java	(working copy)
@@ -428,12 +428,12 @@
           postingsConsumer.finishDoc();
           docCount++;
         }
-        termsConsumer.finishTerm(term, new TermStats(postings.size(), totalTF));
+        termsConsumer.finishTerm(term, new TermStats(postings.size(), doFreq ? totalTF : -1));
         sumTotalTF += totalTF;
         sumDF += postings.size();
       }
 
-      termsConsumer.finish(sumTotalTF, sumDF, seenDocs.cardinality());
+      termsConsumer.finish(doFreq ? sumTotalTF : -1, sumDF, seenDocs.cardinality());
     }
 
     fieldsConsumer.close();
Index: lucene/core/src/test/org/apache/lucene/index/TestCodecs.java
===================================================================
--- lucene/core/src/test/org/apache/lucene/index/TestCodecs.java	(revision 1364739)
+++ lucene/core/src/test/org/apache/lucene/index/TestCodecs.java	(working copy)
@@ -116,7 +116,7 @@
         sumDF += term.docs.length;
         sumTotalTermCount += term.write(termsConsumer);
       }
-      termsConsumer.finish(sumTotalTermCount, sumDF, (int) visitedDocs.cardinality());
+      termsConsumer.finish(omitTF ? -1 : sumTotalTermCount, sumDF, (int) visitedDocs.cardinality());
     }
   }
 
@@ -168,7 +168,7 @@
           postingsConsumer.finishDoc();
         }
       }
-      termsConsumer.finishTerm(text, new TermStats(docs.length, totTF));
+      termsConsumer.finishTerm(text, new TermStats(docs.length, field.omitTF ? -1 : totTF));
       return totTF;
     }
   }
Index: lucene/core/src/java/org/apache/lucene/codecs/TermsConsumer.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/codecs/TermsConsumer.java	(revision 1364739)
+++ lucene/core/src/java/org/apache/lucene/codecs/TermsConsumer.java	(working copy)
@@ -205,6 +205,6 @@
         }
       }
     }
-    finish(sumTotalTermFreq, sumDocFreq, visitedDocs.cardinality());
+    finish(indexOptions == IndexOptions.DOCS_ONLY ? -1 : sumTotalTermFreq, sumDocFreq, visitedDocs.cardinality());
   }
 }
Index: lucene/core/src/java/org/apache/lucene/codecs/PostingsConsumer.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/codecs/PostingsConsumer.java	(revision 1364739)
+++ lucene/core/src/java/org/apache/lucene/codecs/PostingsConsumer.java	(working copy)
@@ -146,6 +146,6 @@
         df++;
       }
     }
-    return new TermStats(df, totTF);
+    return new TermStats(df, indexOptions == IndexOptions.DOCS_ONLY ? -1 : totTF);
   }
 }
Index: lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsWriter.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsWriter.java	(revision 1364739)
+++ lucene/core/src/java/org/apache/lucene/codecs/BlockTreeTermsWriter.java	(working copy)
@@ -896,7 +896,7 @@
         //   w.close();
         // }
       } else {
-        assert sumTotalTermFreq == 0;
+        assert sumTotalTermFreq == 0 || fieldInfo.getIndexOptions() == IndexOptions.DOCS_ONLY && sumTotalTermFreq == -1;
         assert sumDocFreq == 0;
         assert docCount == 0;
       }
Index: lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java	(revision 1364739)
+++ lucene/core/src/java/org/apache/lucene/index/FreqProxTermsWriterPerField.java	(working copy)
@@ -542,11 +542,11 @@
         }
         postingsConsumer.finishDoc();
       }
-      termsConsumer.finishTerm(text, new TermStats(numDocs, totTF));
+      termsConsumer.finishTerm(text, new TermStats(numDocs, writeTermFreq ? totTF : -1));
       sumTotalTermFreq += totTF;
       sumDocFreq += numDocs;
     }
 
-    termsConsumer.finish(sumTotalTermFreq, sumDocFreq, visitedDocs.cardinality());
+    termsConsumer.finish(writeTermFreq ? sumTotalTermFreq : -1, sumDocFreq, visitedDocs.cardinality());
   }
 }