Fix a problem in the csv extension that was triggered when the very first field in the csv file is zero bytes in size.

FossilOrigin-Name: b12ddabf07b5e06bcee8dda3f990af3a131ab52b8fa969ba061b26d38458f31d

1 files changed, 7 insertions, 0 deletions

diff --git a/ext/misc/csv.c b/ext/misc/csv.c
index b51fbad30..915c1cef8 100644
--- a/ext/misc/csv.c
+++ b/ext/misc/csv.c
@@ -280,6 +280,7 @@ static char *csv_read_one_field(CsvReader *p){
     }
     p->cTerm = (char)c;
   }
+  assert( p->z==0 || p->n<p->nAlloc );
   if( p->z ) p->z[p->n] = 0;
   p->bNotFirst = 1;
   return p->z;
@@ -811,6 +812,12 @@ static int csvtabFilter(
   CsvCursor *pCur = (CsvCursor*)pVtabCursor;
   CsvTable *pTab = (CsvTable*)pVtabCursor->pVtab;
   pCur->iRowid = 0;
+
+  /* Ensure the field buffer is always allocated. Otherwise, if the
+  ** first field is zero bytes in size, this may be mistaken for an OOM
+  ** error in csvtabNext(). */
+  if( csv_append(&pCur->rdr, 0) ) return SQLITE_NOMEM;
+
   if( pCur->rdr.in==0 ){
     assert( pCur->rdr.zIn==pTab->zData );
     assert( pTab->iStart>=0 );