Bug Report: Invalid Type in Bindgen IR with foreign_class! Macro

[Florian9M]

Bug Report: Invalid Type in Bindgen IR with foreign_class! Macro

Description

Hello, I'm encountering an issue with the bindgen tool when using the foreign_class! macro. The error message is as follows:

The issue seems to be related to the add_char method, which modifies the information field of the Paris struct by adding a character. When this method is included in the foreign_class! macro, bindgen generates a warning about an invalid type. This suggests that bindgen may have difficulty handling the char type or the mutable reference (&mut self) used in this method.

Code with Error

Here is the code that generates the error:

//Automatically generated by rifgen
use crate::jni_c_header::*;

struct Paris {
    information: String,
}

impl Paris {
    fn new(top: String) -> Paris {
        Paris { information: top }
    }

    fn get_info(&self) -> &str {
        &self.information
    }

    fn add_char(&mut self, c: char) {
        self.information.push(c);
    }
}

foreign_class!(
class Paris {
    self_type Paris;
    constructor Paris::new(top : String)->Paris;
    fn Paris::get_info(& self)->&str; alias getInfo;
    fn Paris::add_char(& mut self , c : char); alias addChar;
}
);

Error

[WARN bindgen::ir::ty] invalid type Type(, kind: Invalid, cconv: 100, decl: Cursor( kind: NoDeclFound, loc: builtin definitions, usr: None), canon: Cursor( kind: NoDeclFound, loc: builtin definitions, usr: None))

Code without Error

The following code does not produce the error:

//Automatically generated by rifgen
use crate::jni_c_header::*;

struct Paris {
    information: String,
}

impl Paris {
    fn new(top: String) -> Paris {
        Paris { information: top }
    }

    fn get_info(&self) -> &str {
        &self.information
    }
}

foreign_class!(
class Paris {
    self_type Paris;
    constructor Paris::new(top : String)->Paris;
    fn Paris::get_info(& self)->&str; alias getInfo;
}
);

Expected Behavior

The bindgen tool should generate valid bindings without any warnings or errors.

Actual Behavior

The bindgen tool generates a warning about an invalid type.

I would appreciate any assistance in resolving this issue. If more information is needed, please let me know.

[Dushistov]

Yes, at the moment flapigen do not support Rust's char to Java's char conversation.
You can work around using &str with one char to pass char from java to rust.

Though error message that you provide is strange.
That I got when I try to compile your code:

 --- stderr
  error in flapigen_test_jni: src/java_glue.rs.in
  parsing of flapigen_test_jni: src/java_glue.rs.in failed
  error: Do not know conversion from Java type to such rust type 'char'
      fn Paris::add_char(& mut self , c : char); alias addChar;
                                          ^^^^

have no idea what bindgen message is about,
may be you should report bindgen part (I suppose you use it to convert jni.h to Rust) to proper issue tracker.

[Florian9M]

Sorry for the late reply. This is the character that was causing the problem. The error code I sent you is part of a similar endless error loop. Whenever something isn't flapigen compatible, bindgen gives me this kind of endless log, and I end up with a buggy vscode or rustrover.

Could this be linked to my configuration or is it already a known problem?