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Overview
Comment:Ensure that the OP_Prev opcode verifies that content has not been deleted out from under the cursor. Fix for ticket [209d31e3161b9e9ff].
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SHA1: 414f0d6a647a4d040b5463c73c5e15e699d85b4c
User & Date: drh 2014-09-29 15:00:28.761
Context
2014-09-29
15:42
Fix the header comment in sqlite3VdbeDeletePriorOpcode(). No changes to code. (check-in: 7fb1626866 user: drh tags: trunk)
15:00
Ensure that the OP_Prev opcode verifies that content has not been deleted out from under the cursor. Fix for ticket [209d31e3161b9e9ff]. (check-in: 414f0d6a64 user: drh tags: trunk)
2014-09-26
18:30
Add an assert() to verify the last-row-id for the database just prior to calling a SQL function. (check-in: d026f0c944 user: mistachkin tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
  assert( pCur->info.nSize==0 );
  if( pCur->eState!=CURSOR_VALID ){
    assert( pCur->eState>=CURSOR_REQUIRESEEK );
    rc = btreeRestoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }








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  assert( cursorHoldsMutex(pCur) );
  assert( pRes!=0 );
  assert( *pRes==0 );
  assert( pCur->skipNext==0 || pCur->eState!=CURSOR_VALID );
  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
  assert( pCur->info.nSize==0 );
  if( pCur->eState!=CURSOR_VALID ){

    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      *pRes = 1;
      return SQLITE_OK;
    }
︙︙
Changes to test/eval.test.
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  execsql {
    CREATE TABLE t2(x,y);
    INSERT INTO t2 SELECT x, x+1 FROM t1 WHERE x<5;
    SELECT x, test_eval('DELETE FROM t2 WHERE x='||x), y FROM t2;
  }
} {1 {} {} 2 {} {} 3 {} {} 4 {} {}}
do_test eval-2.2 {












  execsql {
    SELECT * FROM t2
  }
} {}

# Modify a row while it is being read.
#








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  execsql {
    CREATE TABLE t2(x,y);
    INSERT INTO t2 SELECT x, x+1 FROM t1 WHERE x<5;
    SELECT x, test_eval('DELETE FROM t2 WHERE x='||x), y FROM t2;
  }
} {1 {} {} 2 {} {} 3 {} {} 4 {} {}}
do_test eval-2.2 {
  execsql {
    SELECT * FROM t2
  }
} {}
do_test eval-2.3 {
  execsql {
    INSERT INTO t2 SELECT x, x+1 FROM t1 WHERE x<5;
    SELECT x, test_eval('DELETE FROM t2 WHERE x='||x), y FROM t2
     ORDER BY rowid DESC;
  }
} {4 {} {} 3 {} {} 2 {} {} 1 {} {}}
do_test eval-2.4 {
  execsql {
    SELECT * FROM t2
  }
} {}

# Modify a row while it is being read.
#
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