git/contrib
Avi Halachmi (:avih) 0dbe3d3f16 git-prompt: ta-da! document usage in other shells
With one big exception, git-prompt.sh should now be both almost posix
compliant, and also compatible with most (posix-ish) shells.

That exception is the use of "local" vars in functions, which happens
extensively in the current code, and is not simple to replace with
posix compliant code (but also not impossible).

Luckily, almost all shells support "local" as used by the current
code, with the notable exception of ksh93[u+m], but also the Schily
minimal posix sh (pbosh), and yash in posix mode.

See assessment below that "local" is likely the only blocker in those.

So except mainly ksh93, git-prompt.sh now works in most shells:
- bash, zsh, dash since at least 0.5.8, free/net bsd sh, busybox-ash,
  mksh, openbsd sh, pdksh(!), Schily extended Bourne sh (bosh), yash.

which is quite nice.

As an anecdote, replacing the 1st line in __git_ps1() (local exit=$?)
with these 2 makes it work in all tested shells, even without "local":

  # handles only 0/1 args for simplicity. needs +5 LOC for any $#
  __git_e=$?; local exit="$__git_e" 2>/dev/null ||
    {(eval 'local() { export "$@"; }'; __git_ps1 "$@"); return "$__git_e"; }

Explanation:

  If the shell doesn't have the command "local", define our own
  function "local" which instead does plain (global) assignents.
  Then use __git_ps1 in a subshell to not clober the caller's vars.

  This happens to work because currently there are no name conflicts
  (shadow) at the code, initial value is not assumed (i.e. always
  doing either 'local x=...'  or 'local x;...  x=...'), and assigned
  initial values are quoted (local x="$y"), preventing word split and
  glob expansion (i.e. assignment context is not assumed).

  The last two (always init, quote values) seem to be enough to use
  "local" portably if supported, and otherwise shells indeed differ.

  Uses "eval", else shells with "local" may reject it during parsing.
  We don't need "export", but it's smaller than writing our own loop.

While cute, this approach is not really sustainable because all the
vars become global, which is hard to maintain without conflicts
(but hey, it currently has no conflicts - without even trying...).

However, regardless of being an anecdote, it provides some support to
the assessment that "local" is the only blocker in those shells.

Signed-off-by: Avi Halachmi (:avih) <avihpit@yahoo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-20 08:28:19 -07:00
..
buildsystems cmake: fix build of `t-oidtree` 2024-07-12 14:32:52 -07:00
coccinelle cocci: introduce rules to transform "refs" to pass ref store 2024-05-07 10:06:59 -07:00
completion git-prompt: ta-da! document usage in other shells 2024-08-20 08:28:19 -07:00
contacts
credential osxkeychain: state to skip unnecessary store operations 2024-05-15 14:02:45 -07:00
diff-highlight perl: bump the required Perl version to 5.8.1 from 5.8.0 2023-11-17 07:26:32 +09:00
emacs
examples
fast-import
git-jump git-jump: admit to passing merge mode args to ls-files 2023-10-05 12:55:38 -07:00
git-shell-commands
hooks
long-running-filter
mw-to-git Merge branch 'tz/send-email-negatable-options' into maint-2.43 2024-02-08 16:22:01 -08:00
persistent-https
remote-helpers
stats
subtree contrib/subtree/t: avoid redundant use of cat 2024-03-16 11:08:55 -07:00
thunderbird-patch-inline
update-unicode
vscode path: remove mksnpath() 2024-04-05 09:49:38 -07:00
workdir refs: introduce reftable backend 2024-02-07 08:28:37 -08:00
README doc: fix some typos, grammar and wording issues 2023-10-05 12:55:38 -07:00
coverage-diff.sh contrib/coverage-diff: avoid redundant pipelines 2024-03-16 11:08:57 -07:00
git-resurrect.sh
remotes2config.sh
rerere-train.sh

README

Contributed Software

Although these pieces are available as part of the official git
source tree, they are in somewhat different status.  The
intention is to keep interesting tools around git here, maybe
even experimental ones, to give users an easier access to them,
and to give tools wider exposure, so that they can be improved
faster.

I am not expecting to touch these myself that much.  As far as
my day-to-day operation is concerned, these subdirectories are
owned by their respective primary authors.  I am willing to help
if users of these components and the contrib/ subtree "owners"
have technical/design issues to resolve, but the initiative to
fix and/or enhance things _must_ be on the side of the subtree
owners.  IOW, I won't be actively looking for bugs and rooms for
enhancements in them as the git maintainer -- I may only do so
just as one of the users when I want to scratch my own itch.  If
you have patches to things in contrib/ area, the patch should be
first sent to the primary author, and then the primary author
should ack and forward it to me (git pull request is nicer).
This is the same way as how I have been treating gitk, and to a
lesser degree various foreign SCM interfaces, so you know the
drill.

I expect things that start their life in the contrib/ area
to graduate out of contrib/ once they mature, either by becoming
projects on their own, or moving to the toplevel directory.  On
the other hand, I expect I'll be proposing removal of disused
and inactive ones from time to time.

If you have new things to add to this area, please first propose
it on the git mailing list, and after a list discussion proves
there is general interest (it does not have to be a
list-wide consensus for a tool targeted to a relatively narrow
audience -- for example I do not work with projects whose
upstream is svn, so I have no use for git-svn myself, but it is
of general interest for people who need to interoperate with SVN
repositories in a way git-svn works better than git-svnimport),
submit a patch to create a subdirectory of contrib/ and put your
stuff there.

-jc