1673045 - Increase limit on how many pushes a task can be backfilled, e.g. to the span of two backstops distance (currently 39)

Status: NEW

(Tree Management :: Treeherder, task)

Description

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

At the moment, the limit on how many pushes a task can be backfilled is 25 (adding it to the 25 previous previous pushes). A build/test is supposed to run at least every 20 pushes on autoland (full backstop). If full backstops are affected by bustage, using the limit doesn't provide enough cover to check all possible regressors. Backfilling once with the limit, waiting for the the backfill task on the oldest push and backfilling it again takes minutes. (At the moment blocked by bug 1668693).

Increasing the limit to 39 pushes (2 * 20 pushes distances - 1 backstop) seems reasonable.