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

narrow: drop obsolete support for old Mercurial Not needed since narrow is shipped with core. Differential Revision: https://phab.mercurial-scm.org/D5397

tests: test that narrow preserves bookmarks on widen When widening inserts older commits in the changelog, we have to preserve bookmarks so they are not removed by the call to repair.strip() we temporarily do. We didn't have any tests for that before. Differential Revision: https://phab.mercurial-scm.org/D5396

rebase: clarify that commits that become empty are skipped Our message just said that it created no changes, but we didn't explicitly say that that meant that the the commit was not rebased. It also wasn't clear why it created no changes, so this patch also clarifies that that was because the changes were already in the destination. Differential Revision: https://phab.mercurial-scm.org/D5395

rebase: format commit in usual way when explaining that it became empty We use the _ctxdesc() for other similar messages, so it seems we should use it here too. Differential Revision: https://phab.mercurial-scm.org/D5394

rust: propagate error of index_get_parents() properly Before, rustla_contains() would return 0 on error, and the exception would be cleared or noticed somewhere else. We need to propagate the error from AncestorsIterator up to the FFI surface.

rust: look up HgRevlogIndex_GetParents() from symbol table And removes the unused index_get_parents_checked() function. I expect the Index struct will be turned into a pyobject type, though I haven't written any PoC-level patches yet.

revlog: add public CPython function to get parent revisions Since this is a public function, it validates the input revision, and supports nullrev. index_get_parents_checked() will be replaced by this function.

revlog: rename indexType to HgRevlogIndex_Type as it's a global symbol It follows the CPython naming convention, but uses Hg instead of Py.

revlog: export symbol of indexType The idea is to wrap the index object with rust-cpython. I haven't tried it, but it should be doable. We'll probably need a better interface than raw function pointers to do more in Rust.