SQLite

      for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
        sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
      }
    }

    for(pFKey=sParse.pNewTable->pFKey; pFKey; pFKey=pFKey->pNextFrom){
      for(i=0; i<pFKey->nCol; i++){

        if( bFKOnly==0 && pFKey->aCol[i].iFrom==sCtx.iCol ){
          renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
        }
        if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
         && 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
        ){
          renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);

*/
static void corruptSchema(
  InitData *pData,     /* Initialization context */
  const char *zObj,    /* Object being parsed at the point of error */
  const char *zExtra   /* Error information */
){
  sqlite3 *db = pData->db;
  if( db->mallocFailed ){
    pData->rc = SQLITE_NOMEM_BKPT;
  }else if( pData->pzErrMsg[0]!=0 ){
    /* A error message has already been generated.  Do not overwrite it */
  }else if( pData->mInitFlags & INITFLAG_AlterTable ){
    *pData->pzErrMsg = sqlite3DbStrDup(db, zExtra);
    pData->rc = SQLITE_ERROR;
  }else if( db->flags & SQLITE_WriteSchema ){
    pData->rc = SQLITE_CORRUPT_BKPT;
  }else{
    char *z;
    if( zObj==0 ) zObj = "?";
    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
    if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);

    *pData->pzErrMsg = z;
    pData->rc = SQLITE_CORRUPT_BKPT;
  }

}

/*
** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**

** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
** database.  iDb==1 should never be used.  iDb>=2 is used for
** auxiliary databases.  Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
  int rc;
  int i;
#ifndef SQLITE_OMIT_DEPRECATED
  int size;
#endif
  Db *pDb;
  char const *azArg[4];

  azArg[2] = "CREATE TABLE x(type text,name text,tbl_name text,"
                            "rootpage int,sql text)";
  azArg[3] = 0;
  initData.db = db;
  initData.iDb = iDb;
  initData.rc = SQLITE_OK;
  initData.pzErrMsg = pzErrMsg;
  initData.mInitFlags = mFlags;
  sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
  if( initData.rc ){
    rc = initData.rc;
    goto error_out;
  }

  /* Create a cursor to hold the database open

  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
  assert( db->init.busy==0 );
  ENC(db) = SCHEMA_ENC(db);
  assert( db->nDb>0 );
  /* Do the main schema first */
  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
    rc = sqlite3InitOne(db, 0, pzErrMsg, 0);
    if( rc ) return rc;
  }
  /* All other schemas after the main schema. The "temp" schema must be last */
  for(i=db->nDb-1; i>0; i--){
    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
      rc = sqlite3InitOne(db, i, pzErrMsg, 0);
      if( rc ) return rc;
    }
  }
  if( commit_internal ){
    sqlite3CommitInternalChanges(db);
  }
  return SQLITE_OK;

** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */
  char **pzErrMsg;    /* Error message stored here */
  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
  int rc;             /* Result code stored here */
  u32 mInitFlags;     /* Flags controlling error messages */
} InitData;

/*
** Allowed values for mInitFlags
*/
#define INITFLAG_AlterTable   0x0001  /* This is a reparse after ALTER TABLE */

/*
** Structure containing global configuration data for the SQLite library.
**
** This structure also contains some state information.
*/
struct Sqlite3Config {
  int bMemstat;                     /* True to enable memory status */

void sqlite3ExprListSetSortOrder(ExprList*,int);
void sqlite3ExprListSetName(Parse*,ExprList*,Token*,int);
void sqlite3ExprListSetSpan(Parse*,ExprList*,const char*,const char*);
void sqlite3ExprListDelete(sqlite3*, ExprList*);
u32 sqlite3ExprListFlags(const ExprList*);
int sqlite3Init(sqlite3*, char**);
int sqlite3InitCallback(void*, int, char**, char**);
int sqlite3InitOne(sqlite3*, int, char**, u32);
void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
#ifndef SQLITE_OMIT_VIRTUALTABLE
Module *sqlite3PragmaVtabRegister(sqlite3*,const char *zName);
#endif
void sqlite3ResetAllSchemasOfConnection(sqlite3*);
void sqlite3ResetOneSchema(sqlite3*,int);
void sqlite3CollapseDatabaseArray(sqlite3*);

  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: ParseSchema P1 * * P4 *
**
** Read and parse all entries from the SQLITE_MASTER table of database P1
** that match the WHERE clause P4.  If P4 is a NULL pointer, then the
** entire schema for P1 is reparsed.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;

  assert( iDb>=0 && iDb<db->nDb );
  assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );

#ifndef SQLITE_OMIT_ALTERTABLE
  if( pOp->p4.z==0 ){
    sqlite3SchemaClear(db->aDb[iDb].pSchema);
    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
    rc = sqlite3InitOne(db, iDb, &p->zErrMsg, INITFLAG_AlterTable);
    db->mDbFlags |= DBFLAG_SchemaChange;
  }else
#endif

  {
    zMaster = MASTER_NAME;
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[iDb].zDbSName, zMaster, pOp->p4.z);

  execsql {
    PRAGMA writable_schema=on;
    UPDATE sqlite_master SET sql='nonsense';
  }
  db close
  catch { sqlite3 db test.db }
  catchsql { DROP TRIGGER t2r5 }
} {/1 {malformed database schema .*}/}

finish_test