run-llama/liteparse · critical

Unable to generate bindings

Error message

Unable to generate bindings

What it means

The pdfium-sys build script panics because bindgen failed to generate Rust FFI bindings from the PDFium C headers (the `bindgen::Builder::generate()` call returned an Err). This happens when libclang cannot parse `wrapper.h` or the PDFium headers found under the include directory. It is a build-time panic, so the crate fails to compile with this message as the panic output.

Solutions

1. Install libclang (e.g. `apt install libclang-dev` / `brew install llvm` and set LIBCLANG_PATH) and rebuild.
2. Verify the include directory contains the PDFium public headers (fpdfview.h etc.) and is correctly passed to the build script; fix the path/env var that supplies it.
3. Build with the `bindgen` feature disabled so the pre-generated `bindings.rs` shipped in the crate is used instead of running bindgen.
4. Pin/check the PDFium version whose headers are being parsed; regenerate or update bindgen if the headers use unsupported constructs.

Example fix

// before: failing build with missing libclang
# apt install clang libclang-dev
# export LIBCLANG_PATH=/usr/lib/llvm-14/lib

// or, in Cargo.toml, skip bindgen entirely and use the pre-generated bindings
// before
cargo build -p pdfium-sys --features bindgen
// after
cargo build -p pdfium-sys

# shell — before building
cargo build -p pdfium-sys --features bindgen 2>&1 | grep -q 'Unable to generate bindings' && \
  echo 'check libclang + PDFium headers'
# or programmatically ensure prerequisites:
which clang; echo $LIBCLANG_PATH; ls $PDFIUM_INCLUDE/fpdfview.h

When it happens

Trigger: Building pdfium-sys with the `bindgen` feature enabled and either (a) the PDFium C headers are missing/incomplete in the include dir passed via `-I`, (b) libclang is absent or an incompatible version, or (c) the header contents are malformed/incompatible so the clang parse fails and `generate()` returns Err.

Common situations: Fresh CI/dev machines without libclang installed (e.g. no `libclang-dev` / LLVM installed); a PDFium checkout where the `public/` include dir is wrong or empty; PDFium version changes introducing headers bindgen cannot parse; cross-compiling where the wrong libclang/headers are picked up.

Related errors

• Couldn't write bindings!
• pdfium not loaded — call…
• failed to load pdfium shared library
• no data on stdin (input `-` expects a document piped in…
• no data on stdin (input `-` expects a document piped in…

AI-assisted analysis of run-llama/liteparse@22d2dd8cd7 (2026-09-08). Data as JSON: /api/errors/475d6e5fec24bcb2. Report an issue: GitHub.

Appendix: source

Thrown at crates/pdfium-sys/build.rs:286

        let bindings = bindgen::Builder::default()
            .header("wrapper.h")
            .clang_arg(format!("-I{}", include_dir.display()))
            .allowlist_function("FPDF.*")
            .allowlist_function("FORM_.*")
            .allowlist_function("FPDFText_.*")
            .allowlist_function("FPDFPage.*")
            .allowlist_function("FPDFLink_.*")
            .allowlist_function("FPDFFont_.*")
            .allowlist_type("FPDF.*")
            .allowlist_type("FS_.*")
            .allowlist_var("FPDF.*")
            .allowlist_var("FLAT.*")
            .derive_debug(true)
            .derive_default(true)
            .layout_tests(false)
            .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
            .generate()
            .expect("Unable to generate bindings");

        bindings
            .write_to_file(&out_file)
            .expect("Couldn't write bindings!");
    }

    #[cfg(not(feature = "bindgen"))]
    {
        let _ = include_dir;
        let pregenerated = Path::new(env!("CARGO_MANIFEST_DIR")).join("bindings.rs");
        fs::copy(&pregenerated, &out_file).unwrap_or_else(|e| {
            panic!(
                "Failed to copy pre-generated bindings from {}: {e}",
                pregenerated.display()
            )
        });
    }
}

View on GitHub (pinned to 22d2dd8cd7)