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

graft: use cmdstate.delete() to delete the state file Previous patches start using state.cmdstate() class for statefiles. The class has a function delete() to delete the state file. This patch replaces the existing repo.vfs.unlink() with that delete() function. Differential Revision: https://phab.mercurial-scm.org/D3656

graph: add outputgraph() function, called by ascii() to print the graph to the ui. This allows a cleaner entrypoint for extensions to tweak the graph output without needing to rewrite all of ascii(), or needing to manually guess where the graph nodes/edges end and the rev note portion begins. This patch does not affect graph output or behavior in any way. Differential Revision: https://phab.mercurial-scm.org/D3655

graft: add test for reading old graftstate files with new mechanism This tests the reading of old graftstate file using the new logic. The tests shows that if user is in middle of a graft and then updates their mercurial to the version where we have new graftstate format, we can still read the old graft state format files correctly. Differential Revision: https://phab.mercurial-scm.org/D2597

graft: start using the cmdstate class to read and write data to graftstate This patch replaces the logic to read and write data to graftstate file to use the state.cmdstate() class. The previous graftstate format didn't had any version number on top of that, so we have to catch the CorruptedState error and then read the graftstate in case of old state files. This will help us to implement nice additions to graft commands like `--no-commit`, `--abort`, `--stop` flags. Passing on test-graft.t shows that things are working fine. Differential Revision: https://phab.mercurial-scm.org/D3654

graft: use state.cmdstate() to check whether graftstate exists This is a step towards make graft use the new state.cmdstate() class. This patch replaces the ugly try-except with nice if-else conditionals. Differential Revision: https://phab.mercurial-scm.org/D3652

graft: factor out function to read graft state in separate function Fatcoring out the logic in a separate function will help us in adding conditional logic for different versions of graft state files. Differential Revision: https://phab.mercurial-scm.org/D3651

state: removing remaining instances of opts class variable The cmdstate class used to have a class variable opts which used to be a dict which stored all the data for the state. Recent cleanups removed the use of that variable. There were couple of instances left which are removed by this patch. Differential Revision: https://phab.mercurial-scm.org/D3653

help: mention pattern syntax of latesttag() template function