graft: reuse --user and --date values in `hg graft --continue` (BC) Reading the user and date information from graftstate during `hg graft --continue` will help us in preserving the user and date arguments passed when `hg graft` was called. This patch reads that information and reuses that while running `hg graft --continue`. So after this patch, --user and --date values are preserved even if conflicts occur and user don't need to pass them again. The test changes demonstrate the fix. This is a backward incompatible change but I think of this more as a bug fix. Also thinking about removing the line from `hg help graft` which says --continue does not reapply other flags but need to check what are the other flags which needs to be preserved. Differential Revision: https://phab.mercurial-scm.org/D3659

tests: add test showing --continue not preserving --date and --user flags This patch adds test showing that we don't preserve the user passed --date and --user values in `hg graft`. I was fixing that and realized this is untested. Adding tests before so that behavior change or the fix is easy to realize. Differential Revision: https://phab.mercurial-scm.org/D3658

graft: store user passed date and user information in graftstate Right now, `hg help graft` says: The -c/--continue option does not reapply earlier options, except for --force. which should be treated as a bug. A good user experience is that the commands remember the arguments passed initially and preserve them during `hg graft --continue`. This patch starts storing the user and date information in graftstate if user passed it. Upcoming patches will make sure we preserve that information during --continue and them don't allow user to pass any new arguments with --continue. I don't think there is any another `--continue` flag which allows new options to be passed with it. Differential Revision: https://phab.mercurial-scm.org/D3657