revlog: add revmap back to revlog.addgroup The recent c8b6ed51386b patch removed the linkmapper argument from addgroup, as part of trying to make addgroup more agnostic from the changegroup format. It turns out that the changegroup can't resolve linkrevs while iterating over the deltas, because applying the deltas might affect the linkrev resolution. For example, when applying a series of changelog entries, the linkmapper just returns len(cl). If we're iterating over the deltas without applying them to the changelog, this results in incorrect linkrevs. This was caught by the hgsql extension, which reads the revisions before applying them. The fix is to return linknodes as part of the delta iterator, and let the consumer choose what to do. Differential Revision: https://phab.mercurial-scm.org/D730