Add assert() statements to verify that the SQLITE_OPEN_EXCLUSIVE flag is always passed to the VFS when opening a temporary file.

FossilOrigin-Name: e123da49ccae61d591abded52f4721aa10f20d75935c9a3e3fe826a9b8df2317

src/memjournal.c

@@ -359,6 +359,8 @@ int sqlite3JournalOpen(
 ){
   MemJournal *p = (MemJournal*)pJfd;
 
+  assert( zName || nSpill<0 || (flags & SQLITE_OPEN_EXCLUSIVE) );
+
   /* Zero the file-handle object. If nSpill was passed zero, initialize
   ** it using the sqlite3OsOpen() function of the underlying VFS. In this
   ** case none of the code in this module is executed as a result of calls

src/os.c

@@ -223,6 +223,7 @@ int sqlite3OsOpen(
   ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
   ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
   ** reaching the VFS. */
+  assert( zPath || (flags & SQLITE_OPEN_EXCLUSIVE) );
   rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x1087f7f, pFlagsOut);
   assert( rc==SQLITE_OK || pFile->pMethods==0 );
   return rc;

src/pager.c

@@ -5786,6 +5786,7 @@ static int pager_open_journal(Pager *pPager){
 
         if( pPager->tempFile ){
           flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
+          flags |= SQLITE_OPEN_EXCLUSIVE;
           nSpill = sqlite3Config.nStmtSpill;
         }else{
           flags |= SQLITE_OPEN_MAIN_JOURNAL;