clonebundle: add a `filter_bundle_url` function This function does nothing by default, but give extension the opportunity to alter the URL, typically, this could be used to inject authentication token when serving clone bundle for private repositories.

clonebundles: move the manifest reading in a dedicated function We are about to make the logic more advanced to help hosting solution, so we need to centralize it first.

rhg: support `rhg files` with `ui.relative-paths=false`

rhg: make `rhg files` work if `ui.relative-files=true` is specified

rhg: test `rhg files --config ui.relative-paths ...` Add some tests. All of these are falling back for now, will be fixed in follow-up commits.

cleanup: simplify code

dirstate: better error messages when dirstate is corrupted The current error message "Overflow in dirstate" sounds confusing because it suggests either a certain size limit that's being exceeded, or integer arithmetic overflowing. The reality is just a file being shorter than expected.

rust: remove an unused error variant DirstateMapError::EmptyPath

hg: move unreachable code to where it could be reached

stream-clone: support streamv3 on the cli [hg bundle] We add support and test for this. The support is still experimental, so the various name and identifier will eventually need to be renamed when stream-v3 gets out of experimental.

stream-clone: add the `-exp` prefix to the bundle part We forget to do so in 58adcabc295f, however this is important to prevent "current" client to send incompatible version to future client.

zstd: hack include order to ensure that our zstd.h is found If the regular Python CFLAGS include directories that already have the zstd headers available, a different and possible incompatible version can be picked up otherwise. Sadly, it seems like Python has no easy way to prefix flags before the rest.

exchange: allow passing no includes/excludes to `pull()` I would expect that `exchange.pull(includepats=[])` results in an empty list of include patterns to be passed to the remote, but it doesn't currently because we check for any truthy value instead of checking specifically for `not None`.

stabletailgraph: add test cases challenging the open merge stack This adds three more complex test cases with situations requiring tricky state update in the stack-based iteration (arriving soon).

stabletailgraph: naive version of leap computation This adds a naive reference implementation of the computation of leap and specific leap sets (described in the code documentation). The existing tests are enriched accordingly.