narrow: move adding of narrow server capabilities to core We use the experimental.narrow config option introduced in one of the previous patch and move the functionality of adding narrow server capabilities to core. Differential Revision: https://phab.mercurial-scm.org/D4891

wireprotoserver: move narrow capabilities to wireprototypes.py This is done because wireprotoserver import wireprotov1server, so you cannot import wireprotoserver in wireprotov1server to use the capabilities constants. Differential Revision: https://phab.mercurial-scm.org/D4890

narrow: introduce a config option to check if narrow is enabled or not This patch introduces a new config option experimental.narrow which is set to False by default and set to True by the narrow extension. While moving narrow related logic into core, we need to know at places whether narrow extension is enabled or not. Checking the list of extension enabled is one solution but once narrow is inbuilt, we will definitely want a config option to check whether narrow is turned on or not. So this patch introduces a config option, which will evolve to the main point to turn narrow capability on and off once all the narrow is in core. Differential Revision: https://phab.mercurial-scm.org/D4889

narrow: move the code to generate a widening bundle2 to core This is a part of moving more narrow related bits to core. Differential Revision: https://phab.mercurial-scm.org/D4888

narrow: start returning bundle2 from widen_bundle() Differential Revision: https://phab.mercurial-scm.org/D4838

narrow: the first version of narrow_widen wireprotocol command This patch introduces a wireprotocol command narrow_widen() which will be used to widen a narrow copy using `hg tracked` command provided by narrow extension. The wireprotocol command takes the old and new includes and excludes, common heads, changegroup version, known revs, and a boolean ellipses and generates a bundle2 of the required data and send it. The clients receives the bundle2 and applies that. A bundle2 instead of changegroup because in future we might want to add more things to send while widening. Thanks for martinvonz for the suggestion. I am not sure whether we need changegroup version as an argument to the command as I *think* narrow needs changegroup3 already. The tests shows that we don't exchange phase data now while widening which is nice. Also we don't check for pushkeys, rbc-cache, bookmarks etc. This does not support ellipses cases for now but will be supported in future patches. Since we send bundle2, it won't be hard to plug the ellipses logic in here. The existing code for widening a non-ellipses case is also dropped in this patch. Differential Revision: https://phab.mercurial-scm.org/D4813

remotenames: abort if literal revset pattern matches nothing This is the convention of the other namespace revsets such as tag(). Let's make the remote variants do the same.

remotenames: remove unneeded sorted() from revset implementation The order is constrained by the subset.

remotenames: don't call a set of nodes as "revs"

remotenames: use util.always instead of handcrafted lambda