[bug] Git submodule command interprets switch as argument and switch

The issue is as follows:

R0b0t1@host:~/devel/project$ git submodule add https://github.com/user/project -f Cloning into '/home/R0b0t1/devel/project/-f'...

My .gitignore's first line is *, and then I explicitly allow things. Despite the presence of "project/" in the .gitignore the submodule command says it is ignored. The "force" flag is interpreted as a flag and also as the destination directory.

It is possible the argument parsing code for other commands exhibits this error.

R0b0t1.

On Thu, Aug 17, 2017 at 10:16 PM, R0b0t1 <r030t1@gmail.com> wrote:

That might indicate that another submodule command doesn't cope with submodule names that look like a common flag.

Yes, though these other commands are in C, not in shell. Note that Prathamesh is currently porting the "git submodule" command to C, which would allow us to fix this bug easily.

Also note that the -f is ambigious, what if the user meant to have the submodule at path "-f" ? (This issue comes up in many other commands, for example when a path and a branch name is accepted, the path of a potentially deleted file.

To solve this git accepts a double dash, which signals git that anything after the double dash there are arguments not to be interpreted as a command line flag.

Hi,

R0b0t1 wrote:

Thanks for reporting. Confusingly, I think this is intended behavior. "git help submodule" explains:

	add [-b <branch>] [-f|--force] [--name <name>]
		[--reference <repository>] [--depth <depth>] [--]
		<repository> [<path>]

		Add the given repository as a submodule at the given
		path [etc]

Since the -f comes after <repository>, it is a <path>.

That said, there are a few related things wrong here.

The usage string above says I can put "--" before the <repository> to make things extra unambiguous. But when I try that, I get the following result:

	$ git submodule add -- https://gerrit.googlesource.com/gerrit -f
	Cloning into '/tmp/t/test/-f'...
[...]
	Resolving deltas: 100% (215796/215796), done.
	/usr/lib/git-core/git-submodule: line 261: cd: -f: invalid option
	cd: usage: cd [-L|[-P [-e]] [-@]] [dir]
	Unable to checkout submodule '-f'

If I try to put the "--" between <repository> and <path>, I get another confusing result:

	$ git submodule add https://gerrit.googlesource.com/gerrit -- -f
	'--' already exists in the index

"git help cli" is supposed to give advice about this kind of thing as well --- e.g., it gives some sound advice about what form of flags scripts should use (e.g., to always use the 'stuck' form --name=<name> instead of --name name). But it doesn't mention this issue of flags belonging before other arguments.

Thoughts?

Thanks, Jonathan

On Fri, Aug 18, 2017 at 3:38 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

Not to comment on every response to this bug, but I understand. What is confusing is that the command was failing without being forced, and without thinking I added "-f" at the end. The command succeeded as if I supplied the force flag, but per my experience with other tools, and with other Git commands, "-f" should not be a flag. It should be a path, as you say. However it appears to be both.

To reproduce my situation exactly, add "*" to your .gitignore. The directory "gerrit" should then be ignored, and Git will warn you that the submodule will not be tracked (I may have another issue to report related to this, but I'm still trying to figure out what is going on). However, if you name the directory something else, like "-f", it will still be matched by the .gitignore rule and should not succeed. This is why I think the path is also being interpreted as a flag.

Something else may be happening, but either way the behavior does not seem to be expected nor consistent with other parts of Git.

I have experienced issues with -- before. It has been long enough I have forgotten. Sorry for not being able to provide anything concrete.