Debug derived when not allowed

[dimbleby]

Eg change tests/headers/union_with_big_member.h like this:

-  int b[33];
+  char b[33];

Then the output is like this:

#[repr(C)]
#[derive(Debug, Copy)]
pub struct WithBigArray {
    pub a: __BindgenUnionField<::std::os::raw::c_int>,
    pub b: __BindgenUnionField<[::std::os::raw::c_char; 33usize]>,
    pub bindgen_union_field: [u32; 9usize],
}

But the array b of __BindgenUnionFieldis too large for#[derive(Debug)]` to be allowed.

I hit this with a header file that pulls in pthreads: in particular

union pthread_attr_t
{
  char __size[__SIZEOF_PTHREAD_ATTR_T];
  long int __align;
};

[dimbleby]

Actually on closer inspection I see that b isn't an array at all. But still, the compiler complains like this:

error[E0277]: the trait bound `[i8; 56]: std::fmt::Debug` is not satisfied
   --> src/ffi.rs:712:5
    |
712 |     pub __size: __BindgenUnionField<[::std::os::raw::c_char; 56usize]>,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::fmt::Debug` is not implemented for `[i8; 56]`
    |
    = note: `[i8; 56]` cannot be formatted using `:?`; if it is defined in your crate, add `#[derive(Debug)]` or manually implement it
    = note: required because of the requirements on the impl of `std::fmt::Debug` for `ffi::__BindgenUnionField<[i8; 56]>`
    = note: required because of the requirements on the impl of `std::fmt::Debug` for `&ffi::__BindgenUnionField<[i8; 56]>`
    = note: required for the cast to the object type `std::fmt::Debug`

(that output taken from compiling the pthreads example)

[dimbleby]

By the way, I'd actually prefer not to generate Rust code to match pthreads headers at all - is there a way of excluding such things from the output?

[emilio]

@dimbleby yup! You can pass --whitelist flags with a regex, and we'll only generate stuff that matches that regex, or are used by it recursively.

Thanks for the report! This should be fixed in #248.

[emilio]

One of the pending stuff is writing better documentation in how to filter stuff, I use to point to Stylo's (Servo's style system in Gecko) script, but that's become really complex lately, so I'd rather write generic documentation :)

[dimbleby]

gotcha thanks - and thanks for the impressively quick turnaround on the bug reports!

[emilio]

No problem! And thank you for reporting them! :)