function not loaded: clang_createIndex for clang-9 and llvm-7

[jyn]

$ cargo check
   Compiling yottadb v0.3.0 (/home/joshua/YDBRust)
error: failed to run custom build command for `yottadb v0.3.0 (/home/joshua/YDBRust)`
process didn't exit successfully: `/home/joshua/YDBRust/target/debug/build/yottadb-a199df30696d0c98/build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-env-changed=YOTTADB_NO_PKG_CONFIG
...
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
cargo:rust-link-search=/usr/library/V999_R129/dbg
cargo:rerun-if-changed=wrapper.h

--- stderr
thread 'main' panicked at 'function not loaded: clang_createIndex', /home/joshua/.cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/lib.rs:1659:1
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
$ head -n1 /etc/os-release
PRETTY_NAME="Debian GNU/Linux 10 (buster)"

Steps to replicate (on a debian machine):

$ echo 'deb http://deb.debian.org/debian/ testing main' | sudo tee /etc/apt/sources.list
$ sudo apt update && sudo apt install llvm-9 clang-9 llvm-7
$ cargo check

I ran into this for https://gitlab.com/YottaDB/Lang/YDBRust/-/commit/f18a07d1228a44074033c60bd6d9c192614e80a9, but I bet it would happen for any project using bindgen.

Backtrace

thread 'main' panicked at 'function not loaded: clang_createIndex', /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/lib.rs:1659:1
  stack backtrace:
     0: backtrace::backtrace::libunwind::trace
               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
     1: backtrace::backtrace::trace_unsynchronized
               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
     2: std::sys_common::backtrace::_print_fmt
               at src/libstd/sys_common/backtrace.rs:78
     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:1117
     5: std::io::Write::write_fmt
               at src/libstd/io/mod.rs:1508
     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:198
     9: std::panicking::default_hook
               at src/libstd/panicking.rs:217
    10: std::panicking::rust_panic_with_hook
               at src/libstd/panicking.rs:526
    11: std::panicking::begin_panic
               at /rustc/6c8927b0cf80ceee19386026cf9d7fd4fd9d486f/src/libstd/panicking.rs:456
    12: clang_sys::clang_createIndex::{{closure}}
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/link.rs:159
    13: clang_sys::with_library::{{closure}}
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/link.rs:146
    14: std::thread::local::LocalKey<T>::try_with
               at /rustc/6c8927b0cf80ceee19386026cf9d7fd4fd9d486f/src/libstd/thread/local.rs:263
    15: std::thread::local::LocalKey<T>::with
               at /rustc/6c8927b0cf80ceee19386026cf9d7fd4fd9d486f/src/libstd/thread/local.rs:239
    16: clang_sys::with_library
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/link.rs:144
    17: clang_sys::clang_createIndex
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/clang-sys-0.29.3/src/link.rs:156
    18: bindgen::clang::Index::new
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.3/src/clang.rs:1523
    19: bindgen::ir::context::BindgenContext::new
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.3/src/ir/context.rs:550
    20: bindgen::Bindings::generate
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.3/src/lib.rs:2106
    21: bindgen::Builder::generate
               at /home/joshua/.local/lib/cargo/registry/src/github.com-1ecc6299db9ec823/bindgen-0.53.3/src/lib.rs:1419
    22: build_script_build::main
               at ./build.rs:34
    23: std::rt::lang_start::{{closure}}
               at /rustc/6c8927b0cf80ceee19386026cf9d7fd4fd9d486f/src/libstd/rt.rs:67
    24: std::rt::lang_start_internal::{{closure}}
               at src/libstd/rt.rs:52
    25: std::panicking::try::do_call
               at src/libstd/panicking.rs:348
    26: std::panicking::try
               at src/libstd/panicking.rs:325
    27: std::panic::catch_unwind
               at src/libstd/panic.rs:394
    28: std::rt::lang_start_internal
               at src/libstd/rt.rs:51
    29: std::rt::lang_start
               at /rustc/6c8927b0cf80ceee19386026cf9d7fd4fd9d486f/src/libstd/rt.rs:67
    30: main
    31: __libc_start_main
               at ../csu/libc-start.c:308
    32: _start
  note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[Kyle Mayes]

I tried looking into this, here's my after action report:

• Your steps to replicate did not work in either Debian 8, 9, or 10 Docker containers since those versions of llvm and clang were not available. I tried working around this by installing apt install llvm-10 clang-10 llvm-8 instead since those versions were available in the hope that this similar combination of versions would trigger a similar bug
• I was then able to successfully run the clang-sys tests (which loads and uses clang_createIndex)
• I then attempted to run cargo check for this specific commit in the YDBRust project. This failed because the yottadb binaries were not installed
• I attempted to remedy this by installing the yottadb binaries as specified on the Getting Started page, but I got some error about Debian x86-64 not being supported. I used the suggested installer option to force installation anyway
• After installing and configuring pkg-config, I ran cargo check for the specific commit in YDBRust and got about 10 compile errors about mutability mismatches (using rustc 1.45.1)

At this point my natural laziness kicked in and I gave up.

[jyn]

If you got as far as mutability mismatches that means that bindgen was working, since I call bindgen in the build script.

those versions of llvm and clang were not available

Did you see the first step? They're only available from the testing repos.

Anyway I feel really bad for wasting your time, it turns out the issue is I didn't have libclang-9-dev installed.