clap_derive casing change stringly type

[epage]

Issue by pickfire
Sunday May 09, 2021 at 13:47 GMT
Originally opened as clap-rs/clap#2475

---

Please complete the following tasks

• I have searched the discussions
• I have searched the existing issues

Rust Version

rustc 1.52.0 (88f19c6da 2021-05-03)

Clap Version

3.0.0-beta.2

Minimal reproducible code

use clap::Clap;

#[derive(Debug, Clap)]
struct Opts {
    #[clap(long, conflicts_with = "hello-world")] // I thought it should be hello_world
    one: Option<String>,
    #[clap(long)]
    hello_world: Option<String>,
}

fn main() {
    Opts::parse();
}

It is a bit confusing that conflicts_with only work with the transformed string and the issue is that it only errors on runtime, during compile-time there is no error saying that that is incorrect. Can it be checked during compile-time? It is also confusing that I put hello_world in the struct but I need to use hello-world in the option.

Steps to reproduce the bug with the above code

cargo run

Actual Behaviour

thread 'main' panicked at 'Argument or group 'hello_world' specified in 'conflicts_with*' for 'one' does not exist', /home/ivan/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-3.0.0-beta.2/src/build/app/debug_asserts.rs:158:13

Expected Behaviour

First, using hello_world should work instead of hello-world.

Second, it should error during compile-time.

Additional Context

No response

Debug Output

error[E0432]: unresolved import `clap::Clap`
 --> src/main.rs:1:5
  |
1 | use clap::Clap;
  |     ^^^^^^^^^^ no `Clap` in the root

error: cannot determine resolution for the derive macro `Clap`
 --> src/main.rs:3:17
  |
3 | #[derive(Debug, Clap)]
  |                 ^^^^
  |
  = note: import resolution is stuck, try simplifying macro imports

error: cannot find attribute `clap` in this scope
 --> src/main.rs:5:7
  |
5 |     #[clap(long, conflicts_with = "hello_world")] // I thought it should be helllo_world
  |       ^^^^

error: cannot find attribute `clap` in this scope
 --> src/main.rs:7:7
  |
7 |     #[clap(long)]
  |       ^^^^

error[E0599]: no function or associated item named `parse` found for struct `Opts` in the current scope
  --> src/main.rs:12:11
   |
4  | struct Opts {
   | ----------- function or associated item `parse` not found for this
...
12 |     Opts::parse();
   |           ^^^^^ function or associated item not found in `Opts`

error: aborting due to 5 previous errors

Some errors have detailed explanations: E0432, E0599.
For more information about an error, try `rustc --explain E0432`.
error: could not compile `hello`

To learn more, run the command again with --verbose.

[epage]

Comment by epage
Monday Oct 04, 2021 at 18:07 GMT

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Agreed on not being in v3

Structopt passes cased_name to Arg::with_name, so I think its "broken" there too. So by leaving this, we don't introduce any more of a migration problem than if we change it now.

[epage]

Comment by pksunkara
Saturday Oct 09, 2021 at 00:04 GMT

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I am not exactly sure what the expected behaviour should be.

[epage]

Comment by epage
Saturday Oct 09, 2021 at 10:27 GMT

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I am not exactly sure what the expected behaviour should be.

As a user solely of clap_derive, I do not know of the existence of the "name" field, just what my variables are. I have a variable named hello_world, I assume when working with conflicts_with, I would pass in that variable name.