Create .gitignore even if inside existing repository

[vbrandl]

Describe the problem you are trying to solve

When creating a new cargo project using the cargo new subcommand inside an existing git repository, cargo does not create a .gitignore file. That way, also the target directory will be tracked by git.

Describe the solution you'd like

Even if a new project is created inside another git repository, the .gitignore file should still be created

[dsolisherrera]

Implementing the described solution would be really nice, I just ran into the same issue.

[Iniesta8]

@alexcrichton: What do you think about adding target instead of /target to .gitignore or ignore files of other VCS?

If you do so, subprojects would also be covered by the existing ignore file.

Another approach would be to propagate existing vcs ignore files (see my pull request).

[Flying-Toast]

Instead of defaulting to not creating .gitignore in these situations, cargo should give the option to opt out of creating it by passing cargo new an option such as --workspace-member or --in-workspace. IMO, this would be more correct since there are no circumstances where build artifacts should actually be tracked in VCS.

[agorgl]

Any progress on this?