1 files changed, 38 insertions, 4 deletions

diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index c169b3727..fdf223e3b 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -1895,6 +1895,13 @@ int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
     }
     db->nStatement--;
     p->iStatement = 0;
+
+    /* If the statement transaction is being rolled back, also restore the 
+    ** database handles deferred constraint counter to the value it had when 
+    ** the statement transaction was opened.  */
+    if( eOp==SAVEPOINT_ROLLBACK ){
+      db->nDeferredCons = p->nStmtDefCons;
+    }
   }
   return rc;
 }
@@ -1927,6 +1934,28 @@ void sqlite3VdbeMutexArrayEnter(Vdbe *p){
 #endif
 
 /*
+** This function is called when a transaction opened by the database 
+** handle associated with the VM passed as an argument is about to be 
+** committed. If there are outstanding deferred foreign key constraint
+** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
+**
+** If there are outstanding FK violations and this function returns 
+** SQLITE_ERROR, set the result of the VM to SQLITE_CONSTRAINT and write
+** an error message to it. Then return SQLITE_ERROR.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+int sqlite3VdbeCheckDeferred(Vdbe *p){
+  sqlite3 *db = p->db;
+  if( db->nDeferredCons ){
+    p->rc = SQLITE_CONSTRAINT;
+    sqlite3SetString(&p->zErrMsg, db, "foreign key constraint failed");
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+#endif
+
+/*
 ** This routine is called the when a VDBE tries to halt.  If the VDBE
 ** has made changes and is in autocommit mode, then commit those
 ** changes.  If a rollback is needed, then do the rollback.
@@ -2012,10 +2041,14 @@ int sqlite3VdbeHalt(Vdbe *p){
      && db->writeVdbeCnt==(p->readOnly==0) 
     ){
       if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
-        /* The auto-commit flag is true, and the vdbe program was 
-        ** successful or hit an 'OR FAIL' constraint. This means a commit 
-        ** is required.
-        */
+        if( sqlite3VdbeCheckDeferred(p) ){
+          sqlite3BtreeMutexArrayLeave(&p->aMutex);
+          return SQLITE_ERROR;
+        }
+        /* The auto-commit flag is true, the vdbe program was successful 
+        ** or hit an 'OR FAIL' constraint and there are no deferred foreign
+        ** key constraints to hold up the transaction. This means a commit 
+        ** is required.  */
         rc = vdbeCommit(db, p);
         if( rc==SQLITE_BUSY ){
           sqlite3BtreeMutexArrayLeave(&p->aMutex);
@@ -2024,6 +2057,7 @@ int sqlite3VdbeHalt(Vdbe *p){
           p->rc = rc;
           sqlite3RollbackAll(db);
         }else{
+          db->nDeferredCons = 0;
           sqlite3CommitInternalChanges(db);
         }
       }else{