narrow: keep bookmarks temporarily stripped for as long as commits are The narrow extension also has support for shallowness and for inserting older commits on pull. It works by temporarily stripping newer commits, adding the older commits, then re-applying the stripped bundle. The regular Mercurial server uses that when you widen, although it shouldn't be necessary there. Our Google-internal server does it when the user requests an older commit. Our Google-internal tests fail since 7caf632e30c3 (filecache: unimplement __set__() and __delete__() (API), 2018-10-20). I haven't quite understood the problem, but it's related to the way we temporarily hide bookmarks while the commits they point to are stripped. When a transaction is started, Mercurial tries to read various things from the repo for the transaction summary. That leads to computation of hidden commits, which leads to an attempt to find commits pinned by bookmarks. This is the reason we temporarily hide the bookmarks. I think the aforementioned commit makes the restored bookmarks visible earlier than before (which seems like an improvement), so we can no longer incorrectly rely on the repo._bookmarks field being cached too long (IIUC). This patch makes it so we restore the temporarily hidden bookmarks only after the temporary bundle has been re-applied. It also adapts the code to update the repo.__bookmarks field using the pattern described in the aforementioned commit instead of writing directly to the fiels. I have spent many hours trying to understand what was going on here, but I still don't know if this can also happen without our custom server. So this patch unfortunately does not add any tests; I have only been able to test the fix using our Google-internal tests. Differential Revision: https://phab.mercurial-scm.org/D5398