chore: generate ffi headers/docs without building the crates

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["dash", "dash-network", "dash-network-ffi", "hashes", "internals", "fuzz", "rpc-client", "rpc-json", "rpc-integration-test", "key-wallet", "key-wallet-ffi", "key-wallet-manager", "dash-spv", "dash-spv-ffi", "test-utils"]
+members = ["dash", "dash-network", "dash-network-ffi", "hashes", "internals", "fuzz", "rpc-client", "rpc-json", "rpc-integration-test", "key-wallet", "key-wallet-ffi", "key-wallet-manager", "dash-spv", "dash-spv-ffi", "test-utils", "ffi-header-gen"]
 resolver = "2"
 
 [workspace.package]

contrib/verify_ffi.py

@@ -9,18 +9,17 @@
 FFI_CRATES = ["key-wallet-ffi", "dash-spv-ffi"]
 
 
-def build_ffi_crates(repo_root: Path) -> bool:
-    """Build all FFI crates to regenerate headers."""
-    print("  Building FFI crates...")
+def regenerate_headers(repo_root: Path) -> bool:
+    """Regenerate FFI headers using the ffi-header-gen workspace binary."""
+    print("  Generating FFI headers...")
     result = subprocess.run(
-        ["cargo", "build", "--quiet", "--target-dir", "target/verify-ffi"]
-        + [f"-p={crate}" for crate in FFI_CRATES],
+        ["cargo", "run", "--quiet", "-p", "ffi-header-gen", "--", str(repo_root)],
         cwd=repo_root,
         capture_output=True,
         text=True
     )
     if result.returncode != 0:
-        print("Build failed:", file=sys.stderr)
+        print("Header generation failed:", file=sys.stderr)
         if result.stderr:
             print(result.stderr, file=sys.stderr)
         return False
@@ -48,8 +47,8 @@ def main():
 
     print("Regenerating FFI headers and documentation")
 
-    # Build all FFI crates first
-    if not build_ffi_crates(repo_root):
+    # Generate headers
+    if not regenerate_headers(repo_root):
         sys.exit(1)
 
     # Generate docs in parallel

dash-spv-ffi/CLAUDE.md

@@ -22,9 +22,9 @@ cargo build --release --target aarch64-apple-ios-sim
 ```
 
 ### Header Generation
-The C header is auto-generated by the build script. To regenerate manually:
+The C header is auto-generated by the build script via the `ffi-header-gen` workspace crate. To regenerate all FFI headers manually:
 ```bash
-cbindgen --config cbindgen.toml --crate dash-spv-ffi --output include/dash_spv_ffi.h
+cargo run -p ffi-header-gen
 ```
 
 ### Unified SDK Build

dash-spv-ffi/Cargo.toml

@@ -33,15 +33,15 @@ key-wallet-manager = { path = "../key-wallet-manager" }
 rand = "0.8"
 clap = { version = "4.5", features = ["derive"] }
 
+[build-dependencies]
+ffi-header-gen = { path = "../ffi-header-gen" }
+
 [dev-dependencies]
 tempfile = "3.8"
 serial_test = "3.0"
 env_logger = "0.10"
 dashcore-test-utils = { path = "../test-utils" }
 
-[build-dependencies]
-cbindgen = "0.29"
-
 [[bin]]
 name = "dash-spv-ffi"
 path = "src/bin/ffi_cli.rs"

dash-spv-ffi/build.rs

@@ -3,25 +3,12 @@ use std::path::PathBuf;
 
 fn main() {
     let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
-    let output_path = PathBuf::from(&crate_dir).join("include");
+    let crate_path = PathBuf::from(&crate_dir);
 
-    std::fs::create_dir_all(&output_path).unwrap();
-
-    // Ensure the build script reruns when header-relevant files change
     println!("cargo:rerun-if-changed=cbindgen.toml");
     println!("cargo:rerun-if-changed=src");
 
-    let config = cbindgen::Config::from_file("cbindgen.toml")
-        .expect("cbindgen config missing or invalid: cbindgen.toml");
-
-    match cbindgen::Builder::new().with_crate(&crate_dir).with_config(config).generate() {
-        Ok(bindings) => {
-            bindings.write_to_file(output_path.join("dash_spv_ffi.h"));
-            println!("cargo:warning=Generated C header at {:?}", output_path);
-        }
-        Err(e) => {
-            // Fail the build to avoid shipping stale headers
-            panic!("Failed to generate C header via cbindgen: {}", e);
-        }
+    if let Err(e) = ffi_header_gen::generate_header(&crate_path, "dash_spv_ffi.h") {
+        panic!("{}", e);
     }
 }

ffi-header-gen/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "ffi-header-gen"
+version = { workspace = true }
+edition = "2021"
+publish = false
+description = "Generates C headers for FFI crates using cbindgen"
+
+[lib]
+name = "ffi_header_gen"
+path = "src/lib.rs"
+
+[[bin]]
+name = "ffi-header-gen"
+path = "src/main.rs"
+
+[dependencies]
+cbindgen = "0.29"

ffi-header-gen/src/lib.rs

@@ -0,0 +1,28 @@
+use std::path::Path;
+
+use cbindgen::Config;
+
+/// Generates a C header file for the given crate directory.
+///
+/// Loads `cbindgen.toml` from `crate_dir`, runs cbindgen, and writes the
+/// header to `<crate_dir>/include/<header_name>`.
+pub fn generate_header(crate_dir: &Path, header_name: &str) -> Result<(), String> {
+    let config_path = crate_dir.join("cbindgen.toml");
+    let output_dir = crate_dir.join("include");
+    let output_path = output_dir.join(header_name);
+
+    std::fs::create_dir_all(&output_dir)
+        .map_err(|e| format!("failed to create {}: {}", output_dir.display(), e))?;
+
+    let config = Config::from_file(&config_path)
+        .map_err(|e| format!("failed to load {}: {}", config_path.display(), e))?;
+
+    let bindings = cbindgen::Builder::new()
+        .with_crate(crate_dir)
+        .with_config(config)
+        .generate()
+        .map_err(|e| format!("failed to generate header for {}: {}", crate_dir.display(), e))?;
+
+    bindings.write_to_file(&output_path);
+    Ok(())
+}

ffi-header-gen/src/main.rs

@@ -0,0 +1,46 @@
+use std::path::PathBuf;
+use std::process;
+
+use ffi_header_gen::generate_header;
+
+struct FfiCrate {
+    dir: &'static str,
+    header: &'static str,
+}
+
+const FFI_CRATES: &[FfiCrate] = &[
+    FfiCrate {
+        dir: "key-wallet-ffi",
+        header: "key_wallet_ffi.h",
+    },
+    FfiCrate {
+        dir: "dash-spv-ffi",
+        header: "dash_spv_ffi.h",
+    },
+];
+
+fn main() {
+    let repo_root = std::env::args()
+        .nth(1)
+        .map(PathBuf::from)
+        .unwrap_or_else(|| std::env::current_dir().expect("failed to get current directory"));
+
+    let mut failed = false;
+
+    for ffi in FFI_CRATES {
+        let crate_dir = repo_root.join(ffi.dir);
+        match generate_header(&crate_dir, ffi.header) {
+            Ok(()) => {
+                eprintln!("generated {}", crate_dir.join("include").join(ffi.header).display())
+            }
+            Err(e) => {
+                eprintln!("{}", e);
+                failed = true;
+            }
+        }
+    }
+
+    if failed {
+        process::exit(1);
+    }
+}

key-wallet-ffi/Cargo.toml

@@ -30,7 +30,7 @@ libc = "0.2"
 hex = "0.4"
 
 [build-dependencies]
-cbindgen = "0.29"
+ffi-header-gen = { path = "../ffi-header-gen" }
 
 [dev-dependencies]
 tempfile = "3.0"

key-wallet-ffi/build.rs

@@ -1,5 +1,4 @@
 // Build script for key-wallet-ffi
-// Generates C header file using cbindgen
 
 use std::env;
 use std::path::PathBuf;
@@ -18,24 +17,14 @@ fn main() {
         _ => {}
     }
 
-    // Generate C header file using cbindgen
+    // Generate C header file
     let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
-    let output_path = PathBuf::from(&crate_dir).join("include/key_wallet_ffi.h");
+    let crate_path = PathBuf::from(&crate_dir);
 
-    // Create include directory if it doesn't exist
-    std::fs::create_dir_all(output_path.parent().unwrap()).ok();
+    println!("cargo:rerun-if-changed=cbindgen.toml");
+    println!("cargo:rerun-if-changed=src");
 
-    match cbindgen::Builder::new()
-        .with_crate(&crate_dir)
-        .with_config(cbindgen::Config::from_file("cbindgen.toml").unwrap_or_default())
-        .generate()
-    {
-        Ok(bindings) => {
-            bindings.write_to_file(&output_path);
-            println!("cargo:warning=Generated C header at {:?}", output_path);
-        }
-        Err(e) => {
-            println!("cargo:warning=Failed to generate C header: {}", e);
-        }
+    if let Err(e) = ffi_header_gen::generate_header(&crate_path, "key_wallet_ffi.h") {
+        println!("cargo:warning=Failed to generate C header: {}", e);
     }
 }