File-lines seems to require stdin

[barafael]

I ran rustfmt like this:

rustfmt --unstable-features ==file-lines '[{"file":"presentation.md","range":[31,33]}]'

This puts rustfmt in a prompt where it awaits terminal input. When I hit CTRL+D to terminate, I get:

Warning: Extra file listed in file_lines option '/path/to/example-project/presentation.md'

This also happens when the file in question ends with .rs.

This behaviour is similar to passing "stdin" as file.

I am wondering if I am using this incorrectly or what is going on here?

$> rustfmt --version
rustfmt 1.5.2-nightly (473f916 2023-05-03)

[ytmimi]

@barafael unfortunately, rustfmt doesn't format rust code blocks in markdown files, so what you're trying to do won't work. There's an open issue for formatting rust code blocks in markdown files, but i's pretty low priority right now #2036.

[ytmimi]

That being said, when you don't pass a file to rustfmt like rustfmt /path/to/file.rs rustfmt expects that the input you want to format will come from stdin. You can see this comment and the following discussion for more details.