Re: [9fans] Git/fs: Possibly Usable

[Kyohei Kadota <lufia@lufia.org>]

Cool! It's very interesting what implement Git in native Plan 9 style to me.

2019年4月2日(火) 13:48 <ori@eigenstate.org>:
>
> It was mentioned on this list a short while ago. Now, it's
> more or less at the point where it works for me. Expect
> many bugs and problems, and many more missing tools, but
> "the rest is just scripting".
>
> One caveat I have: Git's index file format is a bit
> boneheaded, so I'm ignoring it. The index doesn't affect
> the wire protocol, so this isn't an interoperability issue,
> unless you share the same physical repository on both
> Plan 9 and Unix. If you do, expect them to get out of
> sync on uncommitted but added files.
>
> In fact, the entire concept of the staging area has been
> removed, as it's both confusing and clunky. There are now
> only three states that files can be in: 'untracked',
> 'dirty', and 'committed'. Tracking is done with empty
> files under .git/index9/{removed,tracked}/path/to/file.
>
> It's implemented in Plan 9 flavor C, and provides tools
> for writing repository contents, and a file system for
> read-only access, which will mirror the current state of
> the repository.
>
> The code is here: https://bitbucket.org/oridb/git9
>
> Install with `mk install`. There's no recursive binding
> of directories, so you need to union /rc/bin/git and
> $objtype/bin/git` by hand.
>
> Documentation has not yet been written. You'll need to
> read the source.
>
> Some usage examples:
>
>         git/clone git://git.eigenstate.org/git/ori/mc.git
>         git/log
>         cd subdir/name
>         git/add foo.c
>         git/commit
>         git/push
>
> Scripts will generally mount git/fs as needed to do
> their work, but if you want to browse the repository
> manually, run it yourself. You'll get `/n/git` mounted,
> with the following contents:
>
>         /n/git/object:  The objects in the repo.
>         /n/git/branch:  The branches in the repo.
>         /n/git/ctl:             A file showing the status of the repo.
>                                         Currently, it only shows the current branch.
>
> Commits are presented as directories with the following
> contents:
>
>         author: A file containing the author name
>         hash:   A file containing the commit hash
>         parent: A file containing the commit parents, one per line.
>         msg:    A file containing the log message for that commit
>         tree:   A directory containing a view of the repository.
>
> So, for example:
>
>         % ls /n/git/branch/heads/master
>         /n/git/branch/heads/master/author
>         /n/git/branch/heads/master/hash
>         /n/git/branch/heads/master/msg
>         /n/git/branch/heads/master/parent
>         /n/git/branch/heads/master/tree
>         % cat /n/git/branch/heads/master/hash
>         7d539a7c08aba3f31b3913e0efef11c43ea9
>
>         # This is the same commit, with the same contents.
>         % ls /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef
>         /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef/author
>         /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef/hash
>         /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef/msg
>         /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef/parent
>         /n/git/object/7d539a7c08aba3f31b3913e0efef11c43ea9f9ef/tree
>
>         # what git/diff will hopefully do more concisely soon, filtering
>         # out the non-git files.
>         ape/diff -ur /n/git/branch/heads/master/tree .
>         Only in .: .git
>         Only in .: debug
>         diff -ur /n/git/branch/heads/master/tree/fold.myr ./fold.myr
>         --- /n/git/branch/heads/master/tree/fold.myr    Wed Dec 31 16:00:00 1969
>         +++ ./fold.myr  Mon Apr  1 21:39:06 2019
>         @@ -6,6 +6,8 @@
>                 const foldexpr : (e : expr# -> std.option(constval))
>          ;;
>
>         +/* Look, diffing files just works, and I don't need any fancy glue! */
>         +
>          const foldexpr = {e
>                 match e
>                 | &(`Eident &[.sc=`Sclassenum, .name=name, .ty=`Tyenum &(`Body enum)]):
>         Only in .: refs
>
>
> The following utilities and binaries are provided:
>
>         fs:     The git filesystem.
>         fetch:  The protocol bits for getting data from a git server.
>         send:   The protocol bits for sending data to a git server.
>         save:   The gnarly bits for storing the files for a commit.
>         conf:   A program to extract information from a config file.
>         clone:  Clones a repository.
>         commit: Commits a snapshot of the working directory.
>         log:    Prints the contents of a commmit log.
>         add:    Tells the repository to add a file to the next commit.
>         walk:   `du`, but for git status.
>
>
> Supported protocols: git:// and git+ssh://. If someone
> implements others, I'll gladly accept patches.
>
> TODOs:
>         git/mkpatch:    Generate a 'git am' compatible patch.
>         git/apply:      Apply a diff.
>         git/diff:       Wrapper wrapper around git/walk that
>                         diffs the changed files.
>         git/merge:      Yup, what it says on the label. Should
>                         also be a script around git/fs.
>         git/log:        Need to figure out how to make it filter
>                         by files.
>         /n/git/HEAD:    add /n/git/head subtree which points
>                         to the current commit.
>
> ...And a whole bunch more.
>
>