Subject: Re: [PATCH v2 2/2] git-p4: remove "rollback" verb

From: Junio C Hamano <[email-masked]>
Date: Mon, 20 Dec 2021 11:32:04 -0800

Joel Holdsworth <[email-masked]> writes:

> The git-p4 "rollback" verb is described as "A tool to debug the
> multi-branch import. Don't use :)".

;-).

> The implementation provided is of no
> useful benefit to either users or developers.

It is hard to make such a broad "no useful benefit" claim without
giving a bit more analysis [*].  With only that single sentence, it
is far worse justification than saying that "The author tells us not
to use it, and it is not even documented" to convince others why
removal is a good idea.

I'd suggest dropping that sentence (replace it with something we can
objectively verify, like "it is not even documented", if you want to).

Thanks.

[Footnote]

 * what the code tried to do, how it didn't do it well that it was
   clear that it couldn't possibly be useful, etc. etc.

> Signed-off-by: Joel Holdsworth <[email-masked]>
> ---
> Adds Signed-off-by tag
>
>  git-p4.py | 60 -------------------------------------------------------
>  1 file changed, 60 deletions(-)
>
> diff --git a/git-p4.py b/git-p4.py
> index b7ed8e41ff..a7cb321f75 100755
> --- a/git-p4.py
> +++ b/git-p4.py
> @@ -1532,65 +1532,6 @@ def loadUserMapFromCache(self):
>          except IOError:
>              self.getUserMapFromPerforceServer()
>  
> -class P4RollBack(Command):
> -    def __init__(self):
> -        Command.__init__(self)
> -        self.options = [
> -            optparse.make_option("--local", dest="rollbackLocalBranches", action="store_true")
> -        ]
> -        self.description = "A tool to debug the multi-branch import. Don't use :)"
> -        self.rollbackLocalBranches = False
> -
> -    def run(self, args):
> -        if len(args) != 1:
> -            return False
> -        maxChange = int(args[0])
> -
> -        if "p4ExitCode" in p4Cmd("changes -m 1"):
> -            die("Problems executing p4");
> -
> -        if self.rollbackLocalBranches:
> -            refPrefix = "refs/heads/"
> -            lines = read_pipe_lines("git rev-parse --symbolic --branches")
> -        else:
> -            refPrefix = "refs/remotes/"
> -            lines = read_pipe_lines("git rev-parse --symbolic --remotes")
> -
> -        for line in lines:
> -            if self.rollbackLocalBranches or (line.startswith("p4/") and line != "p4/HEAD\n"):
> -                line = line.strip()
> -                ref = refPrefix + line
> -                log = extractLogMessageFromGitCommit(ref)
> -                settings = extractSettingsGitLog(log)
> -
> -                depotPaths = settings['depot-paths']
> -                change = settings['change']
> -
> -                changed = False
> -
> -                if len(p4Cmd("changes -m 1 "  + ' '.join (['%s...@%s' % (p, maxChange)
> -                                                           for p in depotPaths]))) == 0:
> -                    print("Branch %s did not exist at change %s, deleting." % (ref, maxChange))
> -                    system("git update-ref -d %s `git rev-parse %s`" % (ref, ref))
> -                    continue
> -
> -                while change and int(change) > maxChange:
> -                    changed = True
> -                    if self.verbose:
> -                        print("%s is at %s ; rewinding towards %s" % (ref, change, maxChange))
> -                    system("git update-ref %s \"%s^\"" % (ref, ref))
> -                    log = extractLogMessageFromGitCommit(ref)
> -                    settings =  extractSettingsGitLog(log)
> -
> -
> -                    depotPaths = settings['depot-paths']
> -                    change = settings['change']
> -
> -                if changed:
> -                    print("%s rewound to %s" % (ref, change))
> -
> -        return True
> -
>  class P4Submit(Command, P4UserMap):
>  
>      conflict_behavior_choices = ("ask", "skip", "quit")
> @@ -4353,7 +4294,6 @@ def printUsage(commands):
>      "sync" : P4Sync,
>      "rebase" : P4Rebase,
>      "clone" : P4Clone,
> -    "rollback" : P4RollBack,
>      "branches" : P4Branches,
>      "unshelve" : P4Unshelve,
>  }