fix(sqlite): Prevent the execution of 'migrate' script if user_version==0

waku/waku_archive/driver/sqlite_driver/migrations.nim

@@ -3,7 +3,8 @@
 import
   std/[tables, strutils, os],
   stew/results,
-  chronicles
+  chronicles,
+  sqlite3_abi # sqlite3_column_int64
 import
   ../../../common/databases/db_sqlite,
   ../../../common/databases/common
@@ -18,6 +19,37 @@ const SchemaVersion* = 7 # increase this when there is an update in the database
 template projectRoot: string = currentSourcePath.rsplit(DirSep, 1)[0] / ".." / ".." / ".." / ".."
 const MessageStoreMigrationPath: string = projectRoot / "migrations" / "message_store"
 
+proc isSchemaVersion7*(db: SqliteDatabase): DatabaseResult[bool] =
+  ## Temporary proc created to analyse when the table actually belongs to the SchemaVersion 7.
+  ##
+  ## During many nwaku versions, 0.14.0 until 0.18.0, the SchemaVersion wasn't set or checked.
+  ## Docker `nwaku` nodes that start working from these versions, 0.14.0 until 0.18.0, they started
+  ## with this discrepancy: `user_version`== 0 (not set) but Message table with SchemaVersion 7.
+  ##
+  ## We found issues where `user_version` (SchemaVersion) was set to 0 in the database even though
+  ## its scheme structure reflected SchemaVersion 7. In those cases, when `nwaku` re-started to
+  ## apply the migration scripts (in 0.19.0) the node didn't start properly because it tried to
+  ## migrate a database that already had the Schema structure #7, so it failed when changing the PK.
+  ##
+  ## TODO: This was added in version 0.20.0. We might remove this in version 0.30.0, as we
+  ##       could consider that many users use +0.20.0.
+
+  var pkColumns = newSeq[string]()
+  proc queryRowCallback(s: ptr sqlite3_stmt) =
+    let colName = cstring sqlite3_column_text(s, 0)
+    pkColumns.add($colName)
+
+  let query = """SELECT l.name FROM pragma_table_info("Message") as l WHERE l.pk != 0;"""
+  let res = db.query(query, queryRowCallback)
+  if res.isErr():
+    return err("failed to determine the current SchemaVersion: " & $res.error)
+
+  if pkColumns == @["pubsubTopic", "id", "storedAt"]:
+    return ok(true)
+
+  else:
+    info "Not considered schema version 7"
+    ok(false)
 
 proc migrate*(db: SqliteDatabase, targetVersion = SchemaVersion): DatabaseResult[void] =
   ## Compares the `user_version` of the sqlite database with the provided `targetVersion`, then
@@ -30,6 +62,14 @@ proc migrate*(db: SqliteDatabase, targetVersion = SchemaVersion): DatabaseResult
   ## NOTE: Down migration it is not currently supported
   debug "starting message store's sqlite database migration"
 
+  let userVersion = ? db.getUserVersion()
+  let isSchemaVersion7 = ? db.isSchemaVersion7()
+
+  if userVersion == 0'i64 and isSchemaVersion7:
+    info "We found user_version 0 but the database schema reflects the user_version 7"
+    ## Force the correct schema version
+    ? db.setUserVersion( 7 )
+
   let migrationRes = migrate(db, targetVersion, migrationsScriptsDir=MessageStoreMigrationPath)
   if migrationRes.isErr():
     return err("failed to execute migration scripts: " & migrationRes.error)