version = expr ignored when using structs in subcommands

[ajeetdsouza]

structopt ignores explicitly set version numbers when used on a struct inside an enum.

To reproduce:

#[derive(StructOpt)]
enum App {
    Baz(Baz),
}

#[derive(StructOpt)]
#[structopt(about = "testing", version = "v1337")]
struct Baz {}

Now running cargo run -- help baz gives us:

foo-baz 0.1.0
testing

USAGE:
    foo baz

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

This is unexpected, since structopt ignores the version field, but uses the about field.

Related issues:

• version = expr ignored when using subcommands #324
• version = expr ignored, and incorrectly uses env!(CARGO_PKG_VERSION) #283

[CreepySkeleton]

This isn't really a bug. The trick is that you need to annotate the variants, not the underlying struct: the attrs on it aren't used. This is a pretty common mistake people make with doc comments.

use structopt::StructOpt;

#[derive(StructOpt)]
enum App {
    #[structopt(about = "testing", version = "v1337")]
    Baz(Baz),
}

#[derive(StructOpt)]
struct Baz {}

fn main() {
    App::from_args();
}

probe.exe-baz v1337
testing

USAGE:
    probe.exe baz

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

[ajeetdsouza]

@CreepySkeleton true, but in the example I provided, the about field does work, despite the fact that it has been annotated on the struct and not the variant.

This is inconsistent behaviour, since the version field that has been annotated in the same place doesn't work.

[CreepySkeleton]

the about field does work

Yes, and it mustn't. This causes #391.