store: pass matcher to store.datafiles() To get narrow stream clones working, we need a way to filter the storage files using a matcher. This patch adds matcher as an argument to store.walk() and store.datafiles() so that we can filter the files returned according to the matcher. Differential Revision: https://phab.mercurial-scm.org/D4850

streamclone: pass narrowing related info in _walkstreamfiles() This patch build a matcher using the include and exclude arguments we have in generatev2() and pass that matcher into _walkstreamfiles(). This will help us in filtering files we stream depending on the includes and excludes passed in by the user. Differential Revision: https://phab.mercurial-scm.org/D4851

streamclone: new server config and some API changes for narrow stream clones This patch introduces a new server config `experimental.server.stream-narrow-clones` which if set to True will advertise that the server supports narrow stream clones. This patch also pass on the includes and excludes from getbundle command to streamclone generation code. There is a test added to show that the includepats and excludepats are correctly passed. Upcoming patches will implement storage layer filtering for streamclones and then we can remove the temporary error and plug in the whole logic together to make narrow stream clones working. Differential Revision: https://phab.mercurial-scm.org/D5137