merge.mergestate: add a way to get the other side of the merge It's surprising there was no API at all for this until now. In any case this will be needed from custom merge drivers.

commands.resolve: support printing out driver-resolved files There's no user-visible way to mark files as driver-resolved, so this status won't be visible.

histedit: make histedit prune when obsolete is enabled Back in June we made histedit use obsolete markers to cleanup when possible. This was rolled back as part of 54f9561088c7 (which should have only rolled back the --abort stuff, but rolled back everything). This caused a nasty bug when used in conjuction with the inhibit+directaccess extensions where histedit would leave old nodes around even after they had been squashed away. The root of the problem is that we first clean up old nodes, and then we clean up temp nodes. In the first pass, when we obsoleted old nodes, some would become unobsolete because they had temp nodes on top of them, thus making them stick around even after the histedit finished. The fix is to A) move the temp node cleanup to be before the old node cleanup (since they are topological on top of the old nodes), and B) use obsolete markers instead of stripping.

clonebundles: rewrite documentation There are a lot of considerations server operators need to know before deploying clone bundles. They should be documented. So I rewrote the extension docs to contain this information.

exchange: support streaming clone bundles in clone bundles Now that we have support for detecting compatible stream clone bundles in bundle specifications, we can safely add support for applying stream clone bundles to the clone bundles feature.

exchange: parse requirements from stream clone specification string Stream clone bundles can only be consumed if the consumer supports the exact format requirements that were present on the producer. This patch adds support for encoding and verifying the format requirements on the bundle specification string for a stream clone bundle are supported by the local repository. If they aren't, we raise an UnsupportedBundleSpecification, just like we do when an unknown compression or bundle type is encountered. The impetus for this patch is so the clone bundles manifest can advertise stream clone bundles and so clients can filter out stream clones with unsupported format requirements. e.g. a stream clone produced with the not-yet-invented "revlogv2" format will be ignored by clients that only support "revlogv1."

exchange: support parameters in bundle specification strings Sometimes a basic type string is not sufficient for representing the contents of a bundle. Take bundle2 for example: future bundle2 files may contain parts that today's bundle2 parser can't read. Another example is stream clone data. These require clients to support specific repository formats or they won't be able to read the written files. In both scenarios, we need to describe additional metadata beyond the outer container type. Furthermore, this metadata behaves more like an unordered set, so an order-based declaration format (such as static strings) is not sufficient. We introduce support for "parameters" into the bundle specification string. These are essentially key-value pairs that can be used to encode additional metadata about the bundle. Semicolons are used as the delimiter partially to increase similarity to MIME parameter values (see RFC 2231) and because they are relatively safe from the command line (although values will need quotes to avoid interpretation as multiple shell commands). Alternatives considered were spaces (a bit annoying to encode) and '&' (similar to URL query strings) (which will do bad things in a shell if unquoted). The parsing function now returns a dict of parsed parameters and consumers have been updated accordingly.

commands: support consuming stream clone bundles For the same reasons that we don't produce stream clone bundles with `hg bundle`, we don't support consuming stream clone bundles with `hg unbundle`. We introduce a complementary debug command for applying stream clone bundles. This command is mostly to facilitate testing. Although it may be used to manually apply stream clone bundles until a more formal mechanism is (possibly) adopted.