Siddharth Kannan [off-list ref] writes:
Making a change in sha1_name.c will touch a lot of commands
(setup_revisions is called from everywhere in the codebase), so, I am
still trying to figure out how to do this such that the rest of the
codepath remains unchanged.
Changing sha1_name.c is the way to go *if* we want all commands to
support this. Just like other ways to name a revision...
I hope that you do not mind this side-effect, but rather, you intended
for this to happen, right? More commands will start supporting this
shorthand, suddenly. (such as format-patch, whatchanged, diff to name
a very few).
... but: the initial implementation of this '-' shorthand was
special-casing a single command (IIRC, "git checkout") for which the
shorthand was useful.
In a previous discussion, I made an analogy with "cd -" (which is the
source of inspiration of this shorthand AFAIK): "-" did not magically
become "the last visited directory" for all Unix commands, just for
"cd". And in this case, I'm happy with it. For example, I never need
"mkdir -", and I'm happy I can't "rm -fr -" by mistake.
So, it's debatable whether it's a good thing to have all commands
support "-". For example, forcing users to explicitly type "git branch
-d @{1}" and not providing them with a shortcut might be a good thing.
I don't have strong opinion on this: I tend to favor consistency and
supporting "-" everywhere goes in this direction, but I think the
downsides should be considered too. A large part of the exercice here is
to write a good commit message!
Another issue with this is: - is also a common way to say "use stdin
instead of a file", so before enabling - for "previous branch", we need
to make sure it does not introduce any ambiguity. Git does not seem to
use "- for stdin" much (most commands able to read from stdin have an
explicit --stdin option for that), a quick grep in the docs shows only
"git blame --contents -" which is OK because a revision wouldn't make
sense here anyway.
--
Matthieu Moy
http://www-verimag.imag.fr/~moy/
Hello Matthieu,
On 8 February 2017 at 20:10, Matthieu Moy [off-list ref] wrote:
In a previous discussion, I made an analogy with "cd -" (which is the
source of inspiration of this shorthand AFAIK): "-" did not magically
become "the last visited directory" for all Unix commands, just for
"cd". And in this case, I'm happy with it. For example, I never need
"mkdir -", and I'm happy I can't "rm -fr -" by mistake.
So, it's debatable whether it's a good thing to have all commands
support "-". For example, forcing users to explicitly type "git branch
-d @{1}" and not providing them with a shortcut might be a good thing.
builtin/branch.c does not call setup_revisions and remains unaffected
by this patch :)
In my original patch post, I was not explicit about what files call
setup_revisions.
I would like to rectify that with this (grep-ed) list:
* builtin/blame.c
* builtin/diff.c
* builtin/diff-files.c
* builtin/diff-index.c
* builtin/diff-tree.c
* builtin/log.c
* builtin/rev-list.c
* builtin/shortlog.c
* builtin/fast-export.c
* builtin/fmt-merge-msg.c
builtin/add.c
builtin/checkout.c
builtin/commit.c
builtin/merge.c
builtin/pack-objects.c
builtin/revert.c
* marked commands only show information, and don't change anything.
As you might notice, in this list, most commands are not of the `rm` variety,
i.e. something that would delete stuff.
In the next version of this patch, I will definitely include the list
of commands
which are "rm-ish" and affected by this patch.
I don't have strong opinion on this: I tend to favor consistency and
supporting "-" everywhere goes in this direction, but I think the
downsides should be considered too. A large part of the exercice here is
to write a good commit message!
Yes, I prefer consistency very much as well! Having "-" mean the same thing
across a lot of commands is better than having that shorthand only in a few
commands, as it is now. Unless there is a specific confusion that might arise
because of this shorthand inclusion, I think that this shorthand
should be supported
across the board.
(I especially like typing `git checkout - <filename>` which is very handy!)
Another issue with this is: - is also a common way to say "use stdin
instead of a file", so before enabling - for "previous branch", we need
to make sure it does not introduce any ambiguity. Git does not seem to
use "- for stdin" much (most commands able to read from stdin have an
explicit --stdin option for that), a quick grep in the docs shows only
"git blame --contents -" which is OK because a revision wouldn't make
sense here anyway.
Yes, just to jog your memory, this was discussed here [1]
Junio said:
As long as the addition is carefully prepared so that we know it
will not conflict (or be confused by users) with possible other uses
of "-", I do not think we would mind "git branch -D -" and other
commands to learn "-" as a synonym for @{-1}.
--
Matthieu Moy
http://www-verimag.imag.fr/~moy/
Thanks a lot for the review on this patch, Matthieu!
--
Best Regards,
- Siddharth.
[1]: https://public-inbox.org/git/7vmwpitb6k.fsf@alter.siamese.dyndns.org/