Better default behavior for scaffold-created .gitignore files

Problem/Motivation

The core-composer-scaffold plugin has the capability to manage .gitignore files for scaffolded files. This feature can be enabled or disabled in the top-level composer.json file. If it is neither enabled or disabled, then the default value is that the feature auto-disables if the current project is not managed in a git repository, or if the vendor directory has been committed already, and is otherwise enabled.

The default behavior presents a problem for the composer create-project command, because in this instance, there is always a git repository for the new site on the first run of the scaffold operation (create-project asks at the very end if the repository should be kept or removed), but it will never be the case that the vendor directory will be committed. The result is that the user ends up with a collection of .gitignore files, whether they wanted them or not.

Currently, the only way around this is to ensure that all of the initial scaffold files are .gitignored in the source project.

Proposed resolution

We can avoid this problem if we invert the default behavior of the .gitignore management feature:

• Management of .gitignore files is disabled by default.
• If the user has proactively .gitignored the vendor directory (and not explicitly enabled or disabled .gitignore management in composer.json), then the feature will be automatically enabled.

Remaining tasks

• Change the code.
• Update the Scaffold plugin README

User interface changes

None

API changes

None

Data model changes

None

Release notes snippet

n/a