deprecate skip_children option

[scampi]

No description provided.

[jsgf]

Why? We're actively using it to format individual files. Is there some other way to get this functionality?

[calebcartwright]

@jsgf - the new default behavior of rustfmt v2.0 will be to not format sub modules (skip_children) which is why the config option is being deprecated.

An -r/--recursive flag will be added, basically inverting things: rustfmt 2.0 will be disabled by default with an optional opt-in, wheras rusftmt 1.x is enabled by default with an optional opt-out

See also #3587

[jsgf]

Ok that's great!

[jeffomatic]

For folks that are using rustfmt for format-on-save workflows, and are aren't using either 2.0 or the nightlies, here's a script that will emulate --skip-children:

https://gist.github.com/jeffomatic/fa443170b856b1af5ca3aa67e0ea3e65

Hope ya'll don't mind me posting here. I found this thread after stumbling upon rustfmt's somewhat surprising behavior of emitting formatted source of a file's dependencies.