[regression] couldn\'t find any valid shared libraries matching: [\'libclang.so\', \'libclang-*.so\']

[jyn514]

Bindgen Invocation

    let bindings = bindgen::Builder::default()
        .header("wrapper.h")
        .clang_arg(include_path)
        .blacklist_item("YDB_NOTTP")
        // Finish the builder and generate the bindings.
        .generate()
        // Unwrap the Result and panic on failure.
        .expect("Unable to generate bindings");

Actual Results

error: failed to run custom build command for `clang-sys v0.28.1`

Caused by:
  process didn't exit successfully: `/home/joshua/Documents/Programming/yottadb/ydbrust/target/debug/build/clang-sys-0bef6ce726fcb6d1/build-script-build` (exit code: 101)
--- stderr
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "couldn\'t find any valid shared libraries matching: [\'libclang.so\', \'libclang-*.so\'], set the `LIBCLANG_PATH` environment variable to a path where one of these files can be found (invalid: [])"', src/libcore/result.rs:1165:5
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/jiasu.xzqcsaa.nyc.mn-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/jiasu.xzqcsaa.nyc.mn-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:61
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1028
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1412
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:65
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:50
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:188
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:205
  10: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:464
  11: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:373
  12: rust_begin_unwind
             at src/libstd/panicking.rs:302
  13: core::panicking::panic_fmt
             at src/libcore/panicking.rs:139
  14: core::result::unwrap_failed
             at src/libcore/result.rs:1165
  15: core::result::Result<T,E>::unwrap
             at /rustc/73528e339aae0f17a15ffa49a8ac608f50c6cf14/src/libcore/result.rs:933
  16: build_script_build::dynamic::link
             at ./build/dynamic.rs:194
  17: build_script_build::main
             at ./build.rs:78
  18: std::rt::lang_start::{{closure}}
             at /rustc/73528e339aae0f17a15ffa49a8ac608f50c6cf14/src/libstd/rt.rs:61
  19: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:48
  20: std::panicking::try::do_call
             at src/libstd/panicking.rs:287
  21: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:78
  22: std::panicking::try
             at src/libstd/panicking.rs:265
  23: std::panic::catch_unwind
             at src/libstd/panic.rs:396
  24: std::rt::lang_start_internal
             at src/libstd/rt.rs:47
  25: std::rt::lang_start
             at /rustc/73528e339aae0f17a15ffa49a8ac608f50c6cf14/src/libstd/rt.rs:61
  26: main
  27: __libc_start_main
  28: _start

Expected Results

bindgen should successfully find clang in one of the following places:

$ echo $(llvm-config --libdir)/libclang*
/usr/lib/llvm-8/lib/libclang-8.so.1 /usr/lib/llvm-8/lib/libclang.so.1

This works fine with bindgen 0.51, it only breaks with 0.52.

See also KyleMayes/clang-sys#98.

[emilio]

I think this is likely a regression from #1649. Do you use bindgen with default-features = false? If so, you probably want to add the dynamic feature to restore behavior.

[jyn514]

I do use default-features = false, adding the runtime feature fixed the problem! I didn't see documentation for this on docs.rs, possibly because the latest build failed: https://docs.rs/crate/bindgen/0.52.0. It would be nice to document this somewhere for the next person :)