Re: [PATCH 1/3] checkout.c: add strict usage of -- before file_path

"Dannier Castro L" [off-list ref] wrote:

Currently, <checkout> is a complex command able to handle both
branches and files without any distintion other than their names,
taking into account that depending on the type (branch or file),
the functionality is completely different, the easier example:

$ git checkout <branch>  # Switch from current branch to <branch>.
$ git checkout <file>    # Restore <file> from HEAD, discarding
                        # changes if it's necessary.
$ git checkout -- <file> # The same as the last one, only with an
                        # useless '--'.

It's not really "useless".

In the first two commands you give, git guesses whether the first
argument is a branch or a file. In the 3rd, the -- indicates that it
must be a file.

For GIT new users,

Nit: we write Git (for the system) or git (for the command-line tool),
but usually avoid the all-caps GIT.

The solution consists in detect '--' into command args, allowing
the discard of changes and considering the following names as
file paths, otherwise, they are branch names.

This answers the "what?" question, but does not explain why this is a
good change. A good commit message should focus more on the "why?"
question.

While I agree that "git checkout" is a complex command, and would love
to see a simpler syntax at least for the most common operations, I do
not think that this is a good change for several reasons:

* If one considers that this "--" syntax is an issue, then this patch
  is a very partial solution only. Many other commands use the same
  convention (for example "git log <commit>" Vs "git log -- <file>"),
  so changing only one makes git less consistent. Also, note that this
  "--" convention is not git-specific. Try "touch --help" and "touch
  -- --help" for example.

* This breaks backward compatibility. People used to "git checkout
  <file>" won't be able to use it anymore. Scripts using it will
  break. Git avoids breaking backward compatibility, and when there's
  a good reason to do so we need a good transition plan. In this case,
  one possible plan would be to 1) issue a warning whenever "git
  checkout <file>" is used for a while, and then 2) actually forbid
  it. But following this path, I don't think step 2) would actually be
  useful.

Wouldn't "dash_dash_pos != -1" be enough to know whether there's a --?

-- 
Matthieu Moy
https://matthieu-moy.fr/