git2-rs unable to find libgit2 built with `-DEXPERIMENTAL_SHA256=ON`

[K1ngfish3r]

I tried to building gram using export LIBGIT2_NO_VENDOR=1 and with a build of libgit2 with the following flag -DEXPERIMENTAL_SHA256=ON. I then came across this error

|B│      Running `/mason/build/x86_64/2.2.0.tar.gz/target/release/build/libgit2-sys-1f279ea7f9a9f4f3/build-script-build`
│B│ warning: libgit2-sys@0.18.4+1.9.3: no GIT_EXPERIMENTAL_SHA256 constant in headers
│B│ error: failed to run custom build command for `libgit2-sys v0.18.4+1.9.3`
│B│
│B│ Caused by:
│B│   process didn't exit successfully: `/mason/build/x86_64/2.2.0.tar.gz/target/release/build/libgit2-sys-1f279ea7f9a9f4f3/build-script-build` (exit status: 101)
│B│   --- stdout
│B│   cargo:rustc-check-cfg=cfg(libgit2_vendored,libgit2_experimental_sha256,)
│B│   cargo:rerun-if-env-changed=LIBGIT2_NO_VENDOR
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_NO_PKG_CONFIG
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG
│B│   cargo:rerun-if-env-changed=PKG_CONFIG
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_STATIC
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_DYNAMIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
│B│   cargo:rerun-if-env-changed=SYSROOT
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_STATIC
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_DYNAMIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
│B│   cargo:rustc-link-search=native=/usr/lib
│B│   cargo:rustc-link-lib=git2-experimental
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG
│B│   cargo:rerun-if-env-changed=PKG_CONFIG
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_STATIC
│B│   cargo:rerun-if-env-changed=LIBGIT2_EXPERIMENTAL_DYNAMIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_PATH
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
│B│   cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
│B│   cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
│B│   cargo:warning=no GIT_EXPERIMENTAL_SHA256 constant in headers
│B│
│B│   --- stderr
│B│
│B│   thread 'main' (12205) panicked at /mason/build/x86_64/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/libgit2-sys-0.18.4+1.9.3/build.rs:100:13:
│B│   The environment variable `LIBGIT2_NO_VENDOR` has been set but no compatible system libgit2 could be found.
│B│   The build is now aborting. To disable, unset the variable or use `LIBGIT2_NO_VENDOR=0`.
│B│
│B│   stack backtrace:
│B│      0: __rustc::rust_begin_unwind
│B│      1: core::panicking::panic_fmt
│B│      2: build_script_build::main
│B│      3: core::ops::function::FnOnce::call_once
│B│   note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
│B│ warning: build failed, waiting for other jobs to finish...

I dont believe gram (or git2-rs?) was able to find my build of libgit2 using the experimental option, what do? Also is the issue applicable here or in libgit2?

[weihanglo]

The issue is in gram it forces to vendor and you chose no-vendor. That basically incompatible as the experimental SHA256 requires libgit2-experimental.so and I don't think any distro has shipped that prebuilt share library. The only way out is unsetting the no vendor env.

See

• https://codeberg.org/GramEditor/gram/src/commit/3557098f2ed35ed2242d5a0498331d6efd3f1713/Cargo.toml#L379
• https://github.com/rust-lang/git2-rs/blob/main/Cargo.toml#L44-L47