fix: provide host function stubs for ABI generation

cargo-near-build/src/near/abi/generate/dylib.rs

@@ -2,7 +2,13 @@ use std::collections::HashSet;
 use std::fs;
 
 use camino::Utf8Path;
+use eyre::WrapErr;
 
+#[cfg(unix)]
+use std::process::Command;
+
+#[cfg(unix)]
+use crate::cargo_native::ArtifactType;
 use crate::cargo_native::Dylib;
 use crate::pretty_print;
 use crate::types::near::build::output::CompilationArtifact;
@@ -36,6 +42,13 @@ pub fn extract_abi_entries(
         pretty_print::indent_payload(&format!("{:#?}", &near_abi_symbols))
     );
 
+    // User-authored #[no_mangle] functions can reference NEAR host imports.
+    // Those symbols are unresolved on host and would make dlopen fail before
+    // we can call __near_abi_* export functions. Load a small shim library
+    // with no-op definitions so ABI extraction can proceed.
+    #[cfg(unix)]
+    let _host_function_stubs = load_near_host_function_stubs()?;
+
     let mut entries = vec![];
     unsafe {
         let lib = libloading::Library::new(dylib_path.as_str())?;
@@ -67,3 +80,156 @@ pub fn extract_abi_entries(
     }
     Ok(entries)
 }
+
+#[cfg(unix)]
+struct LoadedHostFunctionStubs {
+    _temp_dir: tempfile::TempDir,
+    _library: libloading::os::unix::Library,
+}
+
+#[cfg(unix)]
+fn load_near_host_function_stubs() -> eyre::Result<LoadedHostFunctionStubs> {
+    use libloading::os::unix::{Library, RTLD_GLOBAL, RTLD_LAZY};
+
+    let temp_dir = tempfile::Builder::new()
+        .prefix("cargo-near-abi-host-stubs")
+        .tempdir()?;
+    let source_path = temp_dir.path().join("near_host_stubs.rs");
+    let library_path = temp_dir.path().join(format!(
+        "libnear_host_stubs.{}",
+        <Dylib as ArtifactType>::extension()
+    ));
+
+    fs::write(&source_path, near_host_stubs_source())?;
+
+    let rustc = std::env::var("RUSTC").unwrap_or_else(|_| "rustc".to_string());
+    let output = Command::new(&rustc)
+        .arg("--crate-name")
+        .arg("near_host_stubs")
+        .arg("--crate-type")
+        .arg("cdylib")
+        .arg("--edition=2021")
+        .arg(&source_path)
+        .arg("-o")
+        .arg(&library_path)
+        .output()
+        .wrap_err_with(|| format!("failed to execute `{rustc}` while compiling ABI host stubs"))?;
+
+    if !output.status.success() {
+        eyre::bail!(
+            "failed to compile ABI host stubs with `{}`:\n{}",
+            rustc,
+            String::from_utf8_lossy(&output.stderr)
+        );
+    }
+
+    let library = unsafe { Library::open(Some(library_path.as_os_str()), RTLD_LAZY | RTLD_GLOBAL) }
+        .wrap_err_with(|| {
+            format!(
+                "failed to load ABI host stubs from `{}`",
+                library_path.display()
+            )
+        })?;
+
+    Ok(LoadedHostFunctionStubs {
+        _temp_dir: temp_dir,
+        _library: library,
+    })
+}
+
+#[cfg(unix)]
+fn near_host_stubs_source() -> String {
+    let mut source = String::from("#![allow(non_snake_case)]\n\n");
+    for function in NEAR_HOST_FUNCTIONS {
+        source.push_str("#[unsafe(no_mangle)]\n");
+        source.push_str(&format!(
+            "pub unsafe extern \"C\" fn {function}() -> u64 {{ 0 }}\n\n"
+        ));
+    }
+    source
+}
+
+#[cfg(unix)]
+const NEAR_HOST_FUNCTIONS: &[&str] = &[
+    "read_register",
+    "register_len",
+    "write_register",
+    "current_account_id",
+    "current_contract_code",
+    "refund_to_account_id",
+    "signer_account_id",
+    "signer_account_pk",
+    "predecessor_account_id",
+    "input",
+    "block_index",
+    "block_timestamp",
+    "epoch_height",
+    "storage_usage",
+    "account_balance",
+    "account_locked_balance",
+    "attached_deposit",
+    "prepaid_gas",
+    "used_gas",
+    "random_seed",
+    "sha256",
+    "keccak256",
+    "keccak512",
+    "ripemd160",
+    "ecrecover",
+    "ed25519_verify",
+    "value_return",
+    "panic",
+    "panic_utf8",
+    "log_utf8",
+    "log_utf16",
+    "abort",
+    "promise_create",
+    "promise_then",
+    "promise_and",
+    "promise_batch_create",
+    "promise_batch_then",
+    "promise_set_refund_to",
+    "promise_batch_action_state_init",
+    "promise_batch_action_state_init_by_account_id",
+    "set_state_init_data_entry",
+    "promise_batch_action_create_account",
+    "promise_batch_action_deploy_contract",
+    "promise_batch_action_function_call",
+    "promise_batch_action_function_call_weight",
+    "promise_batch_action_transfer",
+    "promise_batch_action_stake",
+    "promise_batch_action_add_key_with_full_access",
+    "promise_batch_action_add_key_with_function_call",
+    "promise_batch_action_delete_key",
+    "promise_batch_action_delete_account",
+    "promise_batch_action_deploy_global_contract",
+    "promise_batch_action_deploy_global_contract_by_account_id",
+    "promise_batch_action_use_global_contract",
+    "promise_batch_action_use_global_contract_by_account_id",
+    "promise_yield_create",
+    "promise_yield_resume",
+    "promise_results_count",
+    "promise_result",
+    "promise_return",
+    "storage_write",
+    "storage_read",
+    "storage_remove",
+    "storage_has_key",
+    "storage_iter_prefix",
+    "storage_iter_range",
+    "storage_iter_next",
+    "validator_stake",
+    "validator_total_stake",
+    "alt_bn128_g1_multiexp",
+    "alt_bn128_g1_sum",
+    "alt_bn128_pairing_check",
+    "bls12381_p1_sum",
+    "bls12381_p2_sum",
+    "bls12381_g1_multiexp",
+    "bls12381_g2_multiexp",
+    "bls12381_map_fp_to_g1",
+    "bls12381_map_fp2_to_g2",
+    "bls12381_pairing_check",
+    "bls12381_p1_decompress",
+    "bls12381_p2_decompress",
+];

cargo-near-build/src/near/abi/generate/mod.rs

@@ -69,20 +69,28 @@ pub fn procedure(
 
     pretty_print::step("Generating ABI");
 
-    let compile_env = {
-        let compile_env = vec![
+    let (compile_env, hide_warnings_for_compile) = {
+        let mut compile_env = vec![
             ("CARGO_PROFILE_DEV_OPT_LEVEL", "0"),
             ("CARGO_PROFILE_DEV_DEBUG", "0"),
             ("CARGO_PROFILE_DEV_LTO", "off"),
             (env_keys::BUILD_RS_ABI_STEP_HINT, "true"),
         ];
-        [&compile_env, env].concat()
+        compile_env.extend_from_slice(env);
+
+        let mut hide_warnings_for_compile = hide_warnings;
+        if let Some(rustflags) = abi_generation_rustflags(hide_warnings) {
+            compile_env.push((env_keys::RUSTFLAGS, rustflags));
+            hide_warnings_for_compile = false;
+        }
+
+        (compile_env, hide_warnings_for_compile)
     };
     let dylib_artifact = cargo_native::compile::run::<Dylib>(
         &crate_metadata.manifest_path,
         cargo_args.as_slice(),
         compile_env,
-        hide_warnings,
+        hide_warnings_for_compile,
         color,
     )?;
 
@@ -125,3 +133,17 @@ fn strip_docs(abi_root: &mut near_abi::AbiRoot) {
         }
     }
 }
+
+#[cfg(target_os = "macos")]
+fn abi_generation_rustflags(hide_warnings: bool) -> Option<&'static str> {
+    if hide_warnings {
+        Some("-Awarnings -C link-arg=-undefined -C link-arg=dynamic_lookup")
+    } else {
+        Some("-C link-arg=-undefined -C link-arg=dynamic_lookup")
+    }
+}
+
+#[cfg(not(target_os = "macos"))]
+fn abi_generation_rustflags(_hide_warnings: bool) -> Option<&'static str> {
+    None
+}

integration-tests/tests/abi/e2e.rs

@@ -1,7 +1,7 @@
 use cargo_near_build::near_abi::{
     AbiFunction, AbiFunctionKind, AbiJsonParameter, AbiParameters, AbiType,
 };
-use cargo_near_integration_tests::generate_abi_fn;
+use cargo_near_integration_tests::{generate_abi_fn, generate_abi_with};
 use function_name::named;
 use schemars::r#gen::SchemaGenerator;
 
@@ -46,3 +46,42 @@ fn test_simple_function() -> cargo_near::CliResult {
 
     Ok(())
 }
+
+#[test]
+#[named]
+fn test_abi_with_unguarded_no_mangle_function() -> cargo_near::CliResult {
+    let abi_root = generate_abi_with! {
+        Code:
+        use near_sdk::near;
+
+        #[near(contract_state)]
+        #[derive(Default)]
+        pub struct Contract {}
+
+        #[near]
+        impl Contract {
+            pub fn get_value(&self) -> u32 {
+                42
+            }
+        }
+
+        #[unsafe(no_mangle)]
+        pub extern "C" fn custom_function() {
+            unsafe {
+                near_sdk::sys::input(0);
+            }
+        }
+    };
+
+    let function_names = abi_root
+        .body
+        .functions
+        .iter()
+        .map(|function| function.name.as_str())
+        .collect::<Vec<_>>();
+
+    assert!(function_names.contains(&"get_value"));
+    assert!(!function_names.contains(&"custom_function"));
+
+    Ok(())
+}

integration-tests/tests/build/opts.rs

@@ -1,5 +1,5 @@
 use crate::util;
-use cargo_near_integration_tests::{build_fn_with, setup_tracing};
+use cargo_near_integration_tests::{build_fn_with, build_with, setup_tracing};
 use function_name::named;
 use std::fs;
 
@@ -123,6 +123,53 @@ async fn test_build_custom_profile() -> testresult::TestResult {
     Ok(())
 }
 
+#[tokio::test]
+#[named]
+async fn test_build_with_unguarded_no_mangle_function() -> testresult::TestResult {
+    setup_tracing();
+    let build_result = build_with! {
+        Code:
+        use near_sdk::near;
+
+        #[near(contract_state)]
+        #[derive(Default)]
+        pub struct Contract {}
+
+        #[near]
+        impl Contract {
+            pub fn get_value(&self) -> u32 {
+                42
+            }
+        }
+
+        #[unsafe(no_mangle)]
+        pub extern "C" fn custom_function() {
+            unsafe {
+                near_sdk::sys::input(0);
+            }
+        }
+    };
+
+    let abi_root = build_result
+        .abi_root
+        .expect("ABI should be generated for the contract");
+    let function_names = abi_root
+        .body
+        .functions
+        .iter()
+        .map(|function| function.name.as_str())
+        .collect::<Vec<_>>();
+    assert!(function_names.contains(&"get_value"));
+    assert!(!function_names.contains(&"custom_function"));
+
+    let worker = near_workspaces::sandbox().await?;
+    let contract = worker.dev_deploy(&build_result.wasm).await?;
+    let outcome = contract.call("get_value").view().await?;
+    assert_eq!(outcome.json::<u32>()?, 42);
+
+    Ok(())
+}
+
 #[tokio::test]
 #[named]
 async fn test_build_abi_features_separate_from_wasm_features() -> testresult::TestResult {