SQLite

The following script leads to an assertion fault:

PRAGMA recursive_triggers = true;
CREATE TABLE t0(a, b, c UNIQUE);
CREATE UNIQUE INDEX i0 ON t0(b) WHERE a;
CREATE TRIGGER tr0 AFTERE DELETE ON t0 BEGIN
  DELETE FROM t0;
END;
INSERT INTO t0(a,b,c) VALUES(0,0,9),(1,1,1);
REPLACE INTO t0(a,b,c) VALUES(2,0,9);

The problem is that the performance optimization of check-in [bec5b6d4d083556d] (2016-11-08) is subtly incorrect. The idea is sound: it avoids unnecessary seek operations on a cursor if we know that the cursor is unperturbed, and the cursor will be unperturbed if either the INSERT is not a REPLACE or if there are no triggers - either explicit triggers are implicit triggers created by foreign key constraints. The problem is that the conditional only detects INSERT triggers that might fire, and fails to detect DELETE triggers that fire as a consequence of the REPLACE.

The assertion fault was first detected by Manuel Rigger and was reported by private email.

Typo: "AFTERE" in the demo script should be "AFTER", of course.