refactor(bindings/zig): add errors handler and module test

[kassane]

cc: @tisonkun @Xuanwo

• Add Zig Error Handler
• Split tests - BDD test with opendal module (sample use)

[tisonkun]

Thanks for your contribution @kassane! Generally looks good. Coments inline.

[tisonkun]

IIRC we map all unknown error to Unexpected at least for Java bindings. Maybe here is a full conversion - cc @Xuanwo @Ji-Xinyou this can be first handled in C bindings.

[xyjixyjixyji]

In C binding, the unknown error leads to panic, you can see it here since the opendal::Error represents all the errors that could happen. Any ideas? @Xuanwo

[kassane]

It's possible:

Method 1 (unwrap style)

- else => c.OPENDAL_ERROR,
+ else => unreachable,

Method 2

- else => c.OPENDAL_ERROR,
+ else => @panic(str),

Method 3

- else => c.OPENDAL_ERROR,
+ else => @compileError(str),

[xyjixyjixyji]

It's possible:

Method 1 (unwrap style)

- else => c.OPENDAL_ERROR,
+ else => unreachable,

Method 2

- else => c.OPENDAL_ERROR,
+ else => @panic(str),

Method 3

- else => c.OPENDAL_ERROR,
+ else => @compilerError(str),

I personally prefer compilerError one. I was trying to do that in Rust, but rustc does not support that 🤣

[tisonkun]

LGTM.

#2381 (comment) can be a further discussion on error handling policy. I tend to keep the behavior the same with the Rust lib, while @Xuanwo suggest to fallback to Unexpected here #2276 (comment).

[tisonkun]

Merging...

As an under development binding I'd prefer unblock our contributors. Thank you @kassane!