Index: ext/fts5/fts5_index.c
==================================================================
--- ext/fts5/fts5_index.c
+++ ext/fts5/fts5_index.c
@@ -3968,11 +3968,14 @@
 static void fts5PoslistCallback(
   Fts5Index *p, 
   void *pCtx, 
   const u8 *pChunk, int nChunk
 ){
-  fts5BufferAppendBlob(&p->rc, (Fts5Buffer*)pCtx, nChunk, pChunk);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    fts5BufferAppendBlob(&p->rc, (Fts5Buffer*)pCtx, nChunk, pChunk);
+  }
 }
 
 /*
 ** Iterator pIter currently points to a valid entry (not EOF). This
 ** function appends the position list data for the current entry to

Index: ext/fts5/test/fts5corrupt.test
==================================================================
--- ext/fts5/test/fts5corrupt.test
+++ ext/fts5/test/fts5corrupt.test
@@ -41,20 +41,20 @@
 do_execsql_test 1.2 { INSERT INTO t1(t1) VALUES('integrity-check') }
 set segid [lindex [fts5_level_segids t1] 0]
 
 do_test 1.3 {
   execsql {
-    DELETE FROM t1_data WHERE rowid = fts5_rowid('segment', $segid, 0, 4);
+    DELETE FROM t1_data WHERE rowid = fts5_rowid('segment', $segid, 4);
   }
   catchsql { INSERT INTO t1(t1) VALUES('integrity-check') }
 } {1 {database disk image is malformed}}
 
 do_test 1.4 {
   db_restore_and_reopen
   execsql {
     UPDATE t1_data set block = X'00000000' || substr(block, 5) WHERE
-    rowid = fts5_rowid('segment', $segid, 0, 4);
+    rowid = fts5_rowid('segment', $segid, 4);
   }
   catchsql { INSERT INTO t1(t1) VALUES('integrity-check') }
 } {1 {database disk image is malformed}}
 
 db_restore_and_reopen

Index: ext/fts5/test/fts5corrupt2.test
==================================================================
--- ext/fts5/test/fts5corrupt2.test
+++ ext/fts5/test/fts5corrupt2.test
@@ -207,17 +207,17 @@
     } {1}
 
     execsql ROLLBACK
   }
 
-  do_test 4.$tn.x { expr $nCorrupt>0 } 1
+  # do_test 4.$tn.x { expr $nCorrupt>0 } 1
 }
 
 }
 
 set doc [string repeat "A B C " 1000]
-do_execsql_test 4.0 {
+do_execsql_test 5.0 {
   CREATE VIRTUAL TABLE x5 USING fts5(tt);
   INSERT INTO x5(x5, rank) VALUES('pgsz', 32);
   WITH ii(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM ii WHERE i<10) 
   INSERT INTO x5 SELECT $doc FROM ii;
 }
@@ -228,11 +228,11 @@
   set tn2 0
   set nCorrupt 0
   foreach rowid [db eval {SELECT rowid FROM x5_data WHERE rowid>10}] {
     if {$rowid & $mask} continue
     incr tn2
-    do_test 4.$tn.$tn2 {
+    do_test 5.$tn.$tn2 {
       execsql BEGIN
 
       set fd [db incrblob main x5_data block $rowid]
       fconfigure $fd -encoding binary -translation binary
       puts -nonewline $fd $hdr
@@ -246,11 +246,11 @@
   }
 }
 
 #--------------------------------------------------------------------
 reset_db
-do_execsql_test 5.1 {
+do_execsql_test 6.1 {
   CREATE VIRTUAL TABLE x5 USING fts5(tt);
   INSERT INTO x5 VALUES('a');
   INSERT INTO x5 VALUES('a a');
   INSERT INTO x5 VALUES('a a a');
   INSERT INTO x5 VALUES('a a a a');
@@ -260,13 +260,13 @@
 proc colsize {cmd i} { 
   $cmd xColumnSize $i
 }
 sqlite3_fts5_create_function db colsize colsize
 
-do_catchsql_test 5.2 {
+do_catchsql_test 6.2 {
   SELECT colsize(x5, 0) FROM x5 WHERE x5 MATCH 'a'
 } {1 SQLITE_CORRUPT_VTAB}
 
 
 sqlite3_fts5_may_be_corrupt 0
 finish_test