gnd: Normalize ABI artifacts during build to support Hardhat/Truffle formats

Extract normalize_abi_json() to a shared abi module and use it in
copy_abi_to_dir (build.rs) so that Hardhat artifacts ({"abi":[...]})
and Truffle artifacts ({"compilerOutput":{"abi":[...]}}) are stripped
down to the bare ABI array before being written to the build output.
Previously, a raw fs::copy would pass through the metadata wrapper,
causing "expected a valid JSON ABI sequence" failures.

Author: lutter

gnd/src/abi.rs

@@ -0,0 +1,100 @@
+//! ABI normalization utilities.
+//!
+//! Handles extraction of bare ABI arrays from various artifact formats
+//! (raw arrays, Hardhat/Foundry, Truffle).
+
+use anyhow::{anyhow, Context, Result};
+
+/// Normalize ABI JSON to extract the actual ABI array from various artifact formats.
+///
+/// Supports:
+/// - Raw ABI array: `[{...}]`
+/// - Foundry/Hardhat format: `{"abi": [...], ...}`
+/// - Truffle format: `{"compilerOutput": {"abi": [...], ...}, ...}`
+pub fn normalize_abi_json(abi_str: &str) -> Result<serde_json::Value> {
+    let value: serde_json::Value =
+        serde_json::from_str(abi_str).context("Failed to parse ABI JSON")?;
+
+    // Case 1: Already an array - return as-is
+    if value.is_array() {
+        return Ok(value);
+    }
+
+    // Case 2: Object with "abi" field (Foundry/Hardhat format)
+    if let Some(abi) = value.get("abi") {
+        if abi.is_array() {
+            return Ok(abi.clone());
+        }
+    }
+
+    // Case 3: Object with "compilerOutput.abi" field (Truffle format)
+    if let Some(compiler_output) = value.get("compilerOutput") {
+        if let Some(abi) = compiler_output.get("abi") {
+            if abi.is_array() {
+                return Ok(abi.clone());
+            }
+        }
+    }
+
+    Err(anyhow!(
+        "Invalid ABI format: expected an array or an object with 'abi' field"
+    ))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_normalize_abi_json_raw_array() {
+        let raw_abi = r#"[{"type": "event", "name": "Transfer"}]"#;
+        let result = normalize_abi_json(raw_abi).unwrap();
+        assert!(result.is_array());
+        assert_eq!(result.as_array().unwrap().len(), 1);
+    }
+
+    #[test]
+    fn test_normalize_abi_json_hardhat_format() {
+        let hardhat_abi = r#"{
+            "_format": "hh-sol-artifact-1",
+            "contractName": "MyContract",
+            "abi": [{"type": "event", "name": "Transfer"}],
+            "bytecode": "0x..."
+        }"#;
+        let result = normalize_abi_json(hardhat_abi).unwrap();
+        assert!(result.is_array());
+        assert_eq!(result.as_array().unwrap().len(), 1);
+        assert_eq!(
+            result.as_array().unwrap()[0].get("name").unwrap(),
+            "Transfer"
+        );
+    }
+
+    #[test]
+    fn test_normalize_abi_json_truffle_format() {
+        let truffle_abi = r#"{
+            "contractName": "MyContract",
+            "compilerOutput": {
+                "abi": [{"type": "event", "name": "Transfer"}]
+            }
+        }"#;
+        let result = normalize_abi_json(truffle_abi).unwrap();
+        assert!(result.is_array());
+        assert_eq!(result.as_array().unwrap().len(), 1);
+        assert_eq!(
+            result.as_array().unwrap()[0].get("name").unwrap(),
+            "Transfer"
+        );
+    }
+
+    #[test]
+    fn test_normalize_abi_json_invalid_format() {
+        let invalid_abi = r#"{"contractName": "MyContract"}"#;
+        let result = normalize_abi_json(invalid_abi);
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .to_string()
+            .contains("Invalid ABI format"));
+    }
+}

gnd/src/commands/build.rs

@@ -12,6 +12,7 @@ use anyhow::{anyhow, Context, Result};
 use clap::Parser;
 use sha1::{Digest, Sha1};
 
+use crate::abi::normalize_abi_json;
 use crate::compiler::{compile_mapping, find_graph_ts, AscCompileOptions};
 use crate::config::{apply_network_config, get_network_config, load_networks_config};
 use crate::manifest::{load_manifest, resolve_path, DataSource, Manifest, Template};
@@ -649,10 +650,10 @@ fn copy_schema(schema_path: &Path, output_dir: &Path) -> Result<()> {
     Ok(())
 }
 
-/// Copy an ABI file to the specified output directory.
-///
-/// This unified function handles both data source and template ABIs.
-/// The caller specifies the output directory.
+/// Copy an ABI file to the specified output directory, normalizing it to a bare
+/// ABI array. This handles Hardhat/Foundry artifacts (`{"abi": [...]}`) and
+/// Truffle artifacts (`{"compilerOutput": {"abi": [...]}}`) in addition to raw
+/// ABI arrays.
 fn copy_abi_to_dir(abi_name: &str, abi_path: &Path, output_subdir: &Path) -> Result<()> {
     fs::create_dir_all(output_subdir)?;
 
@@ -664,13 +665,17 @@ fn copy_abi_to_dir(abi_name: &str, abi_path: &Path, output_subdir: &Path) -> Res
         &format!("Copy ABI {} to {}", abi_name, output_path.display()),
     );
 
-    fs::copy(abi_path, &output_path).with_context(|| {
-        format!(
-            "Failed to copy ABI from {} to {}",
-            abi_path.display(),
-            output_path.display()
-        )
-    })?;
+    let abi_str = fs::read_to_string(abi_path)
+        .with_context(|| format!("Failed to read ABI file: {}", abi_path.display()))?;
+
+    let normalized = normalize_abi_json(&abi_str)
+        .with_context(|| format!("Failed to normalize ABI: {}", abi_path.display()))?;
+
+    let output_str =
+        serde_json::to_string_pretty(&normalized).context("Failed to serialize normalized ABI")?;
+
+    fs::write(&output_path, output_str)
+        .with_context(|| format!("Failed to write ABI to {}", output_path.display()))?;
 
     Ok(())
 }

gnd/src/commands/codegen.rs

@@ -15,6 +15,7 @@ use ethabi::Contract;
 use graphql_parser::schema as gql;
 use semver::Version;
 
+use crate::abi::normalize_abi_json;
 use crate::codegen::{
     AbiCodeGenerator, Class, ModuleImports, SchemaCodeGenerator, Template as CodegenTemplate,
     TemplateCodeGenerator, TemplateKind, GENERATED_FILE_NOTE,
@@ -220,42 +221,6 @@ fn generate_schema_types(
     Ok(true)
 }
 
-/// Normalize ABI JSON to extract the actual ABI array from various artifact formats.
-///
-/// Supports:
-/// - Raw ABI array: `[{...}]`
-/// - Foundry/Hardhat format: `{"abi": [...], ...}`
-/// - Truffle format: `{"compilerOutput": {"abi": [...], ...}, ...}`
-fn normalize_abi_json(abi_str: &str) -> Result<serde_json::Value> {
-    let value: serde_json::Value =
-        serde_json::from_str(abi_str).context("Failed to parse ABI JSON")?;
-
-    // Case 1: Already an array - return as-is
-    if value.is_array() {
-        return Ok(value);
-    }
-
-    // Case 2: Object with "abi" field (Foundry/Hardhat format)
-    if let Some(abi) = value.get("abi") {
-        if abi.is_array() {
-            return Ok(abi.clone());
-        }
-    }
-
-    // Case 3: Object with "compilerOutput.abi" field (Truffle format)
-    if let Some(compiler_output) = value.get("compilerOutput") {
-        if let Some(abi) = compiler_output.get("abi") {
-            if abi.is_array() {
-                return Ok(abi.clone());
-            }
-        }
-    }
-
-    Err(anyhow!(
-        "Invalid ABI format: expected an array or an object with 'abi' field"
-    ))
-}
-
 /// Preprocess ABI JSON to add default names for unnamed parameters.
 /// The ethabi crate requires all parameters to have names, but Solidity ABIs
 /// can have unnamed parameters. This function adds `param0`, `param1`, etc.
@@ -853,57 +818,4 @@ dataSources:
             "Contract should have static bind method"
         );
     }
-
-    #[test]
-    fn test_normalize_abi_json_raw_array() {
-        let raw_abi = r#"[{"type": "event", "name": "Transfer"}]"#;
-        let result = normalize_abi_json(raw_abi).unwrap();
-        assert!(result.is_array());
-        assert_eq!(result.as_array().unwrap().len(), 1);
-    }
-
-    #[test]
-    fn test_normalize_abi_json_hardhat_format() {
-        let hardhat_abi = r#"{
-            "_format": "hh-sol-artifact-1",
-            "contractName": "MyContract",
-            "abi": [{"type": "event", "name": "Transfer"}],
-            "bytecode": "0x..."
-        }"#;
-        let result = normalize_abi_json(hardhat_abi).unwrap();
-        assert!(result.is_array());
-        assert_eq!(result.as_array().unwrap().len(), 1);
-        assert_eq!(
-            result.as_array().unwrap()[0].get("name").unwrap(),
-            "Transfer"
-        );
-    }
-
-    #[test]
-    fn test_normalize_abi_json_truffle_format() {
-        let truffle_abi = r#"{
-            "contractName": "MyContract",
-            "compilerOutput": {
-                "abi": [{"type": "event", "name": "Transfer"}]
-            }
-        }"#;
-        let result = normalize_abi_json(truffle_abi).unwrap();
-        assert!(result.is_array());
-        assert_eq!(result.as_array().unwrap().len(), 1);
-        assert_eq!(
-            result.as_array().unwrap()[0].get("name").unwrap(),
-            "Transfer"
-        );
-    }
-
-    #[test]
-    fn test_normalize_abi_json_invalid_format() {
-        let invalid_abi = r#"{"contractName": "MyContract"}"#;
-        let result = normalize_abi_json(invalid_abi);
-        assert!(result.is_err());
-        assert!(result
-            .unwrap_err()
-            .to_string()
-            .contains("Invalid ABI format"));
-    }
 }

gnd/src/lib.rs

@@ -1,3 +1,4 @@
+pub mod abi;
 pub mod codegen;
 pub mod commands;
 pub mod compiler;