mixing header and header_contents always panics

[YruamaLairba]

Hi, i'm unable to use header(...) and header_contents(...) for the same bindings generation, libclang always panics.

Input C/C++ Header

Header content doesn't matter, it even happen when headers are empty.

Bindgen Invocation

fn main() {
    bindgen::builder()
        .header("bar.h")
        .header_contents("foo.h", "")
        .generate()
        .expect("Unable to generate bindings");
}

Actual Results

thread 'main' panicked at 'libclang error; possible causes include:
- Invalid flag syntax
- Unrecognized flags
- Invalid flag arguments
- File I/O errors
- Host vs. target architecture mismatch
If you encounter an error missing from this list, please file an issue or a PR!', /home/amaury/.cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.2/src/ir/context.rs:567:13
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:77
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1052
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1426
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:204
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:224
  10: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:472
  11: rust_begin_unwind
             at src/libstd/panicking.rs:380
  12: core::panicking::panic_fmt
             at src/libcore/panicking.rs:85
  13: core::option::expect_failed
             at src/libcore/option.rs:1191
  14: core::option::Option<T>::expect
             at /rustc/b8cedc00407a4c56a3bda1ed605c6fc166655447/src/libcore/option.rs:347
  15: bindgen::ir::context::BindgenContext::new
             at /home/amaury/.cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.2/src/ir/context.rs:567
  16: bindgen::Bindings::generate
             at /home/amaury/.cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.2/src/lib.rs:2106
  17: bindgen::Builder::generate
             at /home/amaury/.cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.2/src/lib.rs:1419
  18: header_contents::main
             at src/main.rs:2
  19: std::rt::lang_start::{{closure}}
             at /rustc/b8cedc00407a4c56a3bda1ed605c6fc166655447/src/libstd/rt.rs:67
  20: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:52
  21: std::panicking::try::do_call
             at src/libstd/panicking.rs:305
  22: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:86
  23: std::panicking::try
             at src/libstd/panicking.rs:281
  24: std::panic::catch_unwind
             at src/libstd/panic.rs:394
  25: std::rt::lang_start_internal
             at src/libstd/rt.rs:51
  26: std::rt::lang_start
             at /rustc/b8cedc00407a4c56a3bda1ed605c6fc166655447/src/libstd/rt.rs:67
  27: main
  28: __libc_start_main
  29: _start
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Expected Results

I just expected a bindings result, not a panic.

[emilio]

Thanks for reporting! I think this is likely a silly error in how we build the argument list in combination of these two options, and should be easy to figure out what is going on.

[curldivergence]

Hey @emilio, I've updated my previous commit and added a couple of tests, it seems there are no regressions this time.

[Dessix]

Is there anything still blocking merge of this PR? I ended up taking a dependency on this and can't cargo-publish with a dependency on an unofficial fork.

[emilio]

Yes, CI was failing, and there was some discussion about some test changes that didn't happen.

Guess we can take the test as is, and I can fix the CI failures.

[Dessix]

@emilio Can we get a patch release with this change integrated?