SQLite

  
    set C1 [$cmd $sql1]
    execsql $at
    set C2 [$cmd $sql2]
  
    sqlite3changegroup grp
    grp schema db main
    breakpoint
    grp add $C1
    grp add $C2
    set T1 [grp output]
    grp delete
  
    db_restore_and_reopen
    execsql $at

  G add $::C2
  G output
  set {} {}
} -test {
  catch { G delete }
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  INSERT INTO t1 VALUES(1, 'one');
  INSERT INTO t1 VALUES(2, 'two');
  ALTER TABLE t1 ADD COLUMN c DEFAULT 'abcdefghijklmnopqrstuvwxyz';
}
faultsim_save_and_close

do_faultsim_test 2 -faults oom-t* -prep {
  faultsim_restore_and_reopen
  db eval {SELECT * FROM sqlite_schema}
} -body {
  sqlite3session S db main
  S attach *
  execsql {
    DELETE FROM t1 WHERE a = 1;
  }
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
  catch { S delete }
}

finish_test

struct sqlite3_session {
  sqlite3 *db;                    /* Database handle session is attached to */
  char *zDb;                      /* Name of database session is attached to */
  int bEnableSize;                /* True if changeset_size() enabled */
  int bEnable;                    /* True if currently recording */
  int bIndirect;                  /* True if all changes are indirect */
  int bAutoAttach;                /* True to auto-attach tables */
  int bImplicitPK;                /* True to handle tables with implicit PK */ int rc;                         /* Non-zero if an error has occurred */

  void *pFilterCtx;               /* First argument to pass to xTableFilter */
  int (*xTableFilter)(void *pCtx, const char *zTab);
  i64 nMalloc;                    /* Number of bytes of data allocated */
  i64 nMaxChangesetSize;
  sqlite3_value *pZeroBlob;       /* Value containing X'' */
  sqlite3_session *pNext;         /* Next session object on same db. */
  SessionTable *pTable;           /* List of attached tables */

      pTab->nEntry++;
  
      /* Figure out how large an allocation is required */
      nByte = sizeof(SessionChange);
      for(i=0; i<(pTab->nCol-pTab->bRowid); i++){
        sqlite3_value *p = 0;
        if( op!=SQLITE_INSERT ){
          /* This may fail if the column has a non-NULL default and was added 
          ** using ALTER TABLE ADD COLUMN after this record was created. */
          rc = pSession->hook.xOld(pSession->hook.pCtx, i, &p);

        }else if( pTab->abPK[i] ){
          TESTONLY(int trc = ) pSession->hook.xNew(pSession->hook.pCtx, i, &p);
          assert( trc==SQLITE_OK );
        }

        if( rc==SQLITE_OK ){
          /* This may fail if SQLite value p contains a utf-16 string that must
          ** be converted to utf-8 and an OOM error occurs while doing so. */
          rc = sessionSerializeValue(0, p, &nByte);
        }
        if( rc!=SQLITE_OK ) goto error_out;
      }
      if( pTab->bRowid ){
        nByte += 9;               /* Size of rowid field - an integer */
      }
  
      /* Allocate the change object */

  pOut->nBuf = 0;
  if( op==SQLITE_INSERT || (op==SQLITE_DELETE && pGrp->bPatch==0) ){
    /* Append the missing default column values to the record. */
    sessionAppendBlob(pOut, aRec, nRec, &rc);
    if( rc==SQLITE_OK && pTab->pDfltStmt==0 ){
      rc = sessionPrepareDfltStmt(pGrp->db, pTab, &pTab->pDfltStmt);
      if( rc==SQLITE_OK && SQLITE_ROW!=sqlite3_step(pTab->pDfltStmt) ){
        rc = sqlite3_errcode(pGrp->db);
      }
    }
    for(ii=nCol; rc==SQLITE_OK && ii<pTab->nCol; ii++){
      int eType = sqlite3_column_type(pTab->pDfltStmt, ii);
      sessionAppendByte(pOut, eType, &rc);
      switch( eType ){
        case SQLITE_FLOAT:
        case SQLITE_INTEGER: {
          i64 iVal;
          if( eType==SQLITE_INTEGER ){
            iVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
          }else{
            double rVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
            memcpy(&iVal, &rVal, sizeof(i64));
          }
          if( SQLITE_OK==sessionBufferGrow(pOut, 8, &rc) ){
            sessionPutI64(&pOut->aBuf[pOut->nBuf], iVal);
            pOut->nBuf += 8;
          }
          break;
        }

        case SQLITE_BLOB:
        case SQLITE_TEXT: {
          int n = sqlite3_column_bytes(pTab->pDfltStmt, ii);

  int iNewReg;                    /* Register for new.* values */
  int iBlobWrite;                 /* Value returned by preupdate_blobwrite() */
  i64 iKey1;                      /* First key value passed to hook */
  i64 iKey2;                      /* Second key value passed to hook */
  Mem *aNew;                      /* Array of new.* values */
  Table *pTab;                    /* Schema object being updated */
  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
  sqlite3_value **apDflt;         /* Array of default values, if required */
};

/*
** An instance of this object is used to pass an vector of values into
** OP_VFilter, the xFilter method of a virtual table.  The vector is the
** set of values on the right-hand side of an IN constraint.
**

    p->aRecord = aRec;
  }

  pMem = *ppValue = &p->pUnpacked->aMem[iIdx];
  if( iIdx==p->pTab->iPKey ){
    sqlite3VdbeMemSetInt64(pMem, p->iKey1);
  }else if( iIdx>=p->pUnpacked->nField ){
    /* This occurs when the table has been extended using ALTER TABLE
    ** ADD COLUMN. The value to return is the default value of the column. */
    Column *pCol = &p->pTab->aCol[iIdx];
    if( pCol->iDflt>0 ){
      if( p->apDflt==0 ){
        int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
        p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
        if( p->apDflt==0 ) goto preupdate_old_out;
      }
      if( p->apDflt[iIdx]==0 ){
        Expr *pDflt = p->pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
        sqlite3_value *pVal = 0;
        rc = sqlite3ValueFromExpr(db, pDflt, ENC(db), pCol->affinity, &pVal);
        if( rc==SQLITE_OK && pVal==0 ){
          rc = SQLITE_CORRUPT_BKPT;
        }
        p->apDflt[iIdx] = pVal;
      }
      *ppValue = p->apDflt[iIdx];
    }else{
      *ppValue = (sqlite3_value *)columnNullValue();
    }
  }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
    if( pMem->flags & (MEM_Int|MEM_IntReal) ){
      testcase( pMem->flags & MEM_Int );
      testcase( pMem->flags & MEM_IntReal );
      sqlite3VdbeMemRealify(pMem);
    }
  }

  if( preupdate.aNew ){
    int i;
    for(i=0; i<pCsr->nField; i++){
      sqlite3VdbeMemRelease(&preupdate.aNew[i]);
    }
    sqlite3DbNNFreeNN(db, preupdate.aNew);
  }
  if( preupdate.apDflt ){
    int i;
    for(i=0; i<pTab->nCol; i++){
      sqlite3ValueFree(preupdate.apDflt[i]);
    }
    sqlite3DbFree(db, preupdate.apDflt);
  }
}
#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */

    CREATE TABLE t8(a, b);
    INSERT INTO t8 VALUES('one', 'two');
    INSERT INTO t8 VALUES('three', 'four');
    ALTER TABLE t8 ADD COLUMN c DEFAULT 'xxx';
  }
}

if 1 {
  # At time of writing, these two are broken. They demonstrate that the
  # sqlite3_preupdate_old() method does not handle the case where ALTER TABLE
  # has been used to add a column with a default value other than NULL.
  #
  # 2024-09-18: These are now fixed.
  #
  do_preupdate_test 7.5.2.1 {
    DELETE FROM t8 WHERE a = 'one'
  } {
    DELETE main t8 1 1   one two xxx
  }
  do_preupdate_test 7.5.2.2 {

  execsql VACUUM
  set ::res
} {}

do_catchsql_test 12.6 {
  INSERT INTO t4 VALUES('def', 3);
} {1 {UNIQUE constraint failed: t4.a}}

#-------------------------------------------------------------------------
# Test adding non-NULL default values using ALTER TABLE.
#
reset_db
db preupdate hook preupdate_hook
do_execsql_test 13.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY);
  INSERT INTO t1 VALUES(100), (200), (300), (400);
}

do_execsql_test 13.1 {
  ALTER TABLE t1 ADD COLUMN b DEFAULT 1234;
  ALTER TABLE t1 ADD COLUMN c DEFAULT 'abcdef';
  ALTER TABLE t1 ADD COLUMN d DEFAULT NULL;
}

do_preupdate_test 13.2 {
  DELETE FROM t1 WHERE a=300
} {DELETE main t1 300 300 0 300 1234 abcdef {}}

do_preupdate_test 13.3 {
  UPDATE t1 SET d='hello world' WHERE a=200
} {
  UPDATE main t1 200 200 0 200 1234 abcdef {} 
                           200 1234 abcdef {hello world}
}

do_preupdate_test 13.4 {
  INSERT INTO t1 DEFAULT VALUES;
} {
  INSERT main t1 401 401 0 401 1234 abcdef {}
}

finish_test