SQLite

  addr1 = sqlite3VdbeAddOp2(v, OP_SorterSort, iSorter, 0); VdbeCoverage(v);
  assert( pKey!=0 || db->mallocFailed || pParse->nErr );
  if( pIndex->onError!=OE_None && pKey!=0 ){
    int j2 = sqlite3VdbeCurrentAddr(v) + 3;
    sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
    addr2 = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
                         pIndex->nKeyCol); VdbeCoverage(v);
    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
  }else{
    addr2 = sqlite3VdbeCurrentAddr(v);
  }
  sqlite3VdbeAddOp2(v, OP_SorterData, iSorter, regRecord);
  sqlite3VdbeAddOp3(v, OP_IdxInsert, iIdx, regRecord, 1);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);

case OP_ResetCount: {
  sqlite3VdbeSetChanges(db, p->nChange);
  p->nChange = 0;
  break;
}

/* Opcode: SorterCompare P1 P2 P3 P4
** Synopsis:  if key(P1)!=trim(r[P3],P4) goto P2
**
** P1 is a sorter cursor. This instruction compares a prefix of the
** the record blob in register P3 against a prefix of the entry that 
** the sorter cursor currently points to.  Only the first P4 fields
** of r[P3] and the sorter record are compared.
**
** If either P3 or the sorter contains a NULL in one of their significant
** fields (not counting the P4 fields at the end which are ignored) then
** the comparison is assumed to be equal.
**
** Fall through to next instruction if the two records compare equal to
** each other.  Jump to P2 if they are different.
*/
case OP_SorterCompare: {
  VdbeCursor *pC;
  int res;
  int nKeyCol;

  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  assert( pOp->p4type==P4_INT32 );
  pIn3 = &aMem[pOp->p3];
  nKeyCol = pOp->p4.i;
  rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
  VdbeBranchTaken(res!=0,2);
  if( res ){
    pc = pOp->p2-1;
  }
  break;
};

** be less than key2. Even if key2 also contains NULL values.
**
** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace
** has been allocated and contains an unpacked record that is used as key2.
*/
static void vdbeSorterCompare(
  const VdbeCursor *pCsr,         /* Cursor object (for pKeyInfo) */
  int nKeyCol,                    /* Num of columns. 0 means "all" */
  const void *pKey1, int nKey1,   /* Left side of comparison */
  const void *pKey2, int nKey2,   /* Right side of comparison */
  int *pRes                       /* OUT: Result of comparison */
){
  KeyInfo *pKeyInfo = pCsr->pKeyInfo;
  VdbeSorter *pSorter = pCsr->pSorter;
  UnpackedRecord *r2 = pSorter->pUnpacked;
  int i;

  if( pKey2 ){
    sqlite3VdbeRecordUnpack(pKeyInfo, nKey2, pKey2, r2);
  }

  if( nKeyCol ){
    r2->nField = nKeyCol;

    for(i=0; i<nKeyCol; i++){
      if( r2->aMem[i].flags & MEM_Null ){
        *pRes = -1;
        return;
      }
    }
    assert( r2->default_rc==0 );
  }

** Otherwise, set *pRes to a negative, zero or positive value if the
** key in pVal is smaller than, equal to or larger than the current sorter
** key.
*/
int sqlite3VdbeSorterCompare(
  const VdbeCursor *pCsr,         /* Sorter cursor */
  Mem *pVal,                      /* Value to compare to current sorter key */
  int nKeyCol,                    /* Only compare this many fields */
  int *pRes                       /* OUT: Result of comparison */
){
  VdbeSorter *pSorter = pCsr->pSorter;
  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  vdbeSorterCompare(pCsr, nKeyCol, pVal->z, pVal->n, pKey, nKey, pRes);
  return SQLITE_OK;
}

# 2014-07-30
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the CREATE UNIQUE INDEX statement
# to verify that ticket 9a6daf340df99ba93c53bcf8fa83d9f28040d2a8
# has been fixed:
#
#  drh added on 2014-07-30 12:33:04:
#
#  The CREATE UNIQUE INDEX on the third line below does not fail even
#  though the x column values are not all unique.
#
#     CREATE TABLE t1(x NOT NULL);
#     INSERT INTO t1 VALUES(1),(2),(2),(3);
#     CREATE UNIQUE INDEX t1x ON t1(x);
#
# If the index is created before the INSERT, then uniqueness is enforced
# at the point of the INSERT. Note that the NOT NULL on the indexed column
# seems to be required in order to exhibit this bug.
#
# "PRAGMA integrity_check" does not detect the resulting malformed database.
# That might be considered a separate issue.
#
# Bisecting shows that this problem was introduced by the addition of
#  WITHOUT ROWID support in version 3.8.2, specifically in check-in
# [c80e229dd9c1230] on 2013-11-07. This problem was reported on the mailing
# list by Pavel Pimenov.  and primary keys, and the UNIQUE constraint
# on table columns
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

foreach {id sql} {
   1 {CREATE TABLE t1(x TEXT PRIMARY KEY, y NOT NULL) WITHOUT ROWID}
   2 {CREATE TABLE t1(x TEXT PRIMARY KEY, y NOT NULL)}
   3 {CREATE TABLE t1(x TEXT PRIMARY KEY, y) WITHOUT ROWID}
   4 {CREATE TABLE t1(x TEXT PRIMARY KEY, y)}
} {
  do_test $id.1 {
    db eval {DROP TABLE IF EXISTS t1}
    db eval $sql
    db eval {INSERT INTO t1(x,y) VALUES(1,1),(2,2),(3,2),(4,3)}
  } {}
  do_test $id.2 {
    catchsql {CREATE UNIQUE INDEX t1y ON t1(y)}
  } {1 {UNIQUE constraint failed: t1.y}}
}

foreach {id sql} {
   5 {CREATE TABLE t1(w,x,y NOT NULL,z NOT NULL,PRIMARY KEY(w,x)) WITHOUT ROWID}
   6 {CREATE TABLE t1(w,x,y NOT NULL,z NOT NULL,PRIMARY KEY(w,x))}
   7 {CREATE TABLE t1(w,x,y NOT NULL,z,PRIMARY KEY(w,x)) WITHOUT ROWID}
   8 {CREATE TABLE t1(w,x,y NOT NULL,z,PRIMARY KEY(w,x))}
   9 {CREATE TABLE t1(w,x,y,z NOT NULL,PRIMARY KEY(w,x)) WITHOUT ROWID}
  10 {CREATE TABLE t1(w,x,y,z NOT NULL,PRIMARY KEY(w,x))}
  11 {CREATE TABLE t1(w,x,y,z,PRIMARY KEY(w,x)) WITHOUT ROWID}
  12 {CREATE TABLE t1(w,x,y,z,PRIMARY KEY(w,x))}
} {
  do_test $id.1 {
    db eval {DROP TABLE IF EXISTS t1}
    db eval $sql
    db eval {INSERT INTO t1(w,x,y,z) VALUES(1,2,3,4),(2,3,3,4)}
  } {}
  do_test $id.2 {
    catchsql {CREATE UNIQUE INDEX t1yz ON t1(y,z)}
  } {1 {UNIQUE constraint failed: t1.y, t1.z}}
}

finish_test