sqlite/test/win32shm.test

# 2026 October 5
#
# 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 script is the behaviour of wal databases on windows
# when some other process has the *-shm file memory-mapped.
#

if {$tcl_platform(platform) ne "windows"} return

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix win32shm

ifcapable !wal {
  finish_test
  return
}

#-------------------------------------------------------------------------
# Each test below simulates a abrupt exit by copying the db, *-wal and 
# *-shm files of an open wal database, then reopens the copy while an 
# external mapping is held on its *-shm file. Since the *-shm file cannot 
# be truncated while it is mapped, these test that recovery still runs and
# all committed data is visible.
#
#   1.1-1.2: The *-shm file is current.
#
#   1.3-1.4: The *-shm file is out of date. If this file were trusted 
#            instead of running recovery, row 4 would be lost.
#
do_execsql_test 1.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 'one');
  INSERT INTO t1 VALUES(2, 'two');
  INSERT INTO t1 VALUES(3, 'three');
} {wal}

do_test 1.1 {
  db_save_and_close
  db_restore
  map_win32_file shmmap test.db-shm
} {shmmap}

sqlite3 db test.db
do_execsql_test 1.2 {
  SELECT * FROM t1
} {1 one 2 two 3 three}

shmmap destroy

do_test 1.3 {
  forcedelete bak-shm
  forcecopy test.db-shm bak-shm
  execsql {
    INSERT INTO t1 VALUES(4, 'four');
  }
  db_save_and_close
  db_restore
  forcecopy bak-shm test.db-shm
  map_win32_file shmmap test.db-shm
} {shmmap}

sqlite3 db test.db
do_execsql_test 1.4 {
  SELECT * FROM t1
} {1 one 2 two 3 three 4 four}

shmmap destroy

finish_test