revlog: split the content verification of a node into a separate method This will be used by LFS to tune what is skipped. In the future, this could also be used by LFS to indicate which nodes tagged with `skipread` are simply in need of a blob fetch, so that they can be done in a batch later. (Currently, `skipread` also indicates censored data and errors.) Additionally, it could be used to cache the sha1 hash value for each blob so that large blobs don't need to be re-read and re-hashed if they are used by multiple nodes. Differential Revision: https://phab.mercurial-scm.org/D7710

verify: update comment to say that lfs doesn't need fulltext to check renames The reason is that `filelog.renamed()` indirectly calls `filelog.revision()`, which is what accesses the full text. However, LFS wraps `filelog.renamed()` and completely handles the case where an LFS blob is in play by using rawdata. I've got a test to demonstrate that this is the case, and prevent regressions. But the `skipread` flag is set on all lfs revisions when using `--no-lfs`, regardless of whether or not the blobs are local. Just above this, that flag is consulted, causing the rename checks to be skipped. That will need to be loosened up first. Differential Revision: https://phab.mercurial-scm.org/D7709