The "bisect" command:

Run various subcommands useful for searching back through the change history for a particular checkin that causes or fixes a problem.

fossil bisect bad ?VERSION?

Identify version VERSION as non-working. If VERSION is omitted, the current checkout is marked as non-working.

fossil bisect good ?VERSION?

Identify version VERSION as working. If VERSION is omitted, the current checkout is marked as working.

fossil bisect log

fossil bisect chart

Show a log of "good", "bad", and "skip" versions. "bisect log" shows the events in the order that they were tested. "bisect chart" shows them in order of check-in.

fossil bisect next

Update to the next version that is halfway between the working and non-working versions.

fossil bisect options ?NAME? ?VALUE?

List all bisect options, or the value of a single option, or set the value of a bisect option.

fossil bisect reset

Reinitialize a bisect session. This cancels prior bisect history and allows a bisect session to start over from the beginning.

fossil bisect skip ?VERSION?

Cause VERSION (or the current checkout if VERSION is omitted) to be ignored for the purpose of the current bisect. This might be done, for example, because VERSION does not compile correctly or is otherwise unsuitable to participate in this bisect.

fossil bisect vlist|ls|status ?-a|--all?

List the versions in between the inner-most "bad" and "good".

fossil bisect ui

Like "fossil ui" except start on a timeline that shows only the check-ins that are part of the current bisect.

fossil bisect undo

Undo the most recent "good", "bad", or "skip" command.