Fix race conditions when printing current status of tasks#399
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eseliger
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Nov 30, 2020
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Code LGTM, I trust you that it fixes the underlying issue :)
LawnGnome
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LGTM. Thanks for fixing this bug! (I'll spare us all the Rust evangelism here.)
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I know :| But to be fair to Go, what we're doing here is communicating between two parts by sharing memory, instead of sharing by communicating. (This is orthogonal to Rust's memory checks that would've probably avoided this, but a thought I had yesterday) |
scjohns
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Apr 24, 2023
* Replace sync.Map with locked access around TaskStatuses * Avoid PrintStatuses being called concurrently * Add changelog entry
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This fixes https://github.com/sourcegraph/sourcegraph/issues/16195 by doing two things:
*TaskStatusinexecutorthrough a mutex to provide a consistent view of all[]*TaskStatus. While we had async.Mapin place it didn't protect us from race conditions, since we passed around pointers toTaskStatusfreely: theexecutorgoroutines would happily write to a*TaskStatusand thecampaignProgressPrinter.PrintStatuswould read[]*TaskStatuswhile they're being updated. Thesync.Mapwas useless in practice. So instead of that, I added a mutex that's used when updating a*TaskStatusand when reading all[]*TaskStatuswhen printing the status.campaignProgressPrinterthrough thePrintStatusescallback: only one execution at a time and if another execution is already in progress it returns.