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WIP: fix(database): make v2->v3 chatlog migration deterministic and FK-safe #129

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jabber.developer2 wants to merge 1 commits from fix/issue-128-migrate-v3-dedup into master
pull from: fix/issue-128-migrate-v3-dedup
merge into: devs:master
Conversation 0 Commits 1 Files Changed 1 +32 -3
1 changed files with 32 additions and 3 deletions
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35
src/database_sqlite.c
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@@ -178,6 +178,9 @@ _sqlite_init(ProfAccount* account)
// replaced_by_db_id Inverse FK: id of the most recent correction.
// Maintained by the AFTER INSERT trigger below so
// readers can follow the chain forward in O(1).
//
// NOTE: any change to these columns (add/remove/reorder) must be mirrored
// in `_migrate_to_v3`, which copies rows via an explicit column list.
const char* query = "CREATE TABLE IF NOT EXISTS `ChatLogs` ("
"`id` INTEGER PRIMARY KEY AUTOINCREMENT, "
"`from_jid` TEXT NOT NULL, "
@@ -865,11 +868,37 @@ _migrate_to_v3(void)
"`replaces_db_id` INTEGER, "
"`replaced_by_db_id` INTEGER)",
// Copy rows into the deduped table. Columns are listed explicitly
// (instead of `SELECT *`) so the migration cannot silently mis-bind
// should the v2/v3 column order ever diverge — keep this list in sync
// with the `ChatLogs_v3_migration` schema above and the live `ChatLogs`
// schema. For duplicate `archive_id` groups (MAM rebroadcasts) keep the
// highest `id` deterministically ("latest insert wins") rather than
// GROUP BY's implementation-defined arbitrary pick.
"INSERT INTO `ChatLogs_v3_migration` "
"SELECT * FROM `ChatLogs` "
"WHERE `archive_id` IS NULL "
"(`id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
"`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
"`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id`) "
"SELECT `id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
"`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
"`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id` "
"FROM `ChatLogs` WHERE `archive_id` IS NULL "
"UNION ALL "
"SELECT * FROM (SELECT * FROM `ChatLogs` WHERE `archive_id` IS NOT NULL GROUP BY `archive_id`)",
"SELECT `id`, `from_jid`, `to_jid`, `from_resource`, `to_resource`, `message`, "
"`timestamp`, `type`, `stanza_id`, `archive_id`, `encryption`, "
"`marked_read`, `replace_id`, `replaces_db_id`, `replaced_by_db_id` "
"FROM `ChatLogs` WHERE `archive_id` IS NOT NULL "
"AND `id` IN (SELECT MAX(`id`) FROM `ChatLogs` WHERE `archive_id` IS NOT NULL GROUP BY `archive_id`)",
// Dropping duplicate rows above can leave the surviving rows' correction
// back-links pointing at ids that no longer exist. NULL them out so the
// XEP-0308 (LMC) chain carries no dangling local foreign keys.
"UPDATE `ChatLogs_v3_migration` SET `replaces_db_id` = NULL "
"WHERE `replaces_db_id` IS NOT NULL "
"AND `replaces_db_id` NOT IN (SELECT `id` FROM `ChatLogs_v3_migration`)",
"UPDATE `ChatLogs_v3_migration` SET `replaced_by_db_id` = NULL "
"WHERE `replaced_by_db_id` IS NOT NULL "
"AND `replaced_by_db_id` NOT IN (SELECT `id` FROM `ChatLogs_v3_migration`)",
"DROP TABLE `ChatLogs` ",
"ALTER TABLE `ChatLogs_v3_migration` RENAME TO `ChatLogs` ",