(In reply to Bert Peers [:bpeers] from comment #1) Thank for the quick response. This was found with a UBSan build on Linux. The log from the run can be found here: https://firefoxci.taskcluster-artifacts.net/YgAivdpvRuS6Icm_eBhCNQ/0/public/logs/live_backing.log > If we can confirm it's the latter that's missing, a simple fix should be to not call `MemStream::write` if `!has_items`. This is very likely the case otherwise we'd probably be seeing a crash.
Bug 1649323 Comment 2 Edit History
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(In reply to Bert Peers [:bpeers] from comment #1) Thank for the quick response. This was found with a UBSan build on Linux. The log from the run can be found here: https://firefoxci.taskcluster-artifacts.net/YgAivdpvRuS6Icm_eBhCNQ/0/public/logs/live_backing.log > If we can confirm it's the latter that's missing, a simple fix should be to not call `MemStream::write` if `!has_items`. This is very likely the case otherwise we'd probably be seeing a crash with other builds.