Add error message on system contract (#1494)

* Add error message on system contract

* fmt

* Small fix

* PR comments

* After-merge fix

* fmt + dependency fix

* Rollback version

* Fix unused imports

* Fix lint error

cmd/soroban-cli/src/commands/contract/fetch.rs

@@ -6,12 +6,15 @@ use std::str::FromStr;
 use std::{fmt::Debug, fs, io};
 
 use clap::{arg, command, Parser};
+use stellar_xdr::curr::{ContractDataEntry, ContractExecutable, ScVal};
 
+use crate::commands::contract::fetch::Error::{ContractIsStellarAsset, UnexpectedContractToken};
 use crate::commands::{global, NetworkRunnable};
 use crate::config::{
     self, locator,
     network::{self, Network},
 };
+use crate::utils::rpc::get_remote_wasm_from_hash;
 use crate::{
     rpc::{self, Client},
     Pwd,
@@ -64,6 +67,13 @@ pub enum Error {
     Network(#[from] network::Error),
     #[error("cannot create contract directory for {0:?}")]
     CannotCreateContractDir(PathBuf),
+    #[error("unexpected contract data {0:?}")]
+    UnexpectedContractToken(ContractDataEntry),
+    #[error(
+        "cannot fetch wasm for contract because the contract is \
+    a network built-in asset contract that does not have a downloadable code binary"
+    )]
+    ContractIsStellarAsset(),
 }
 
 impl From<Infallible> for Error {
@@ -126,6 +136,15 @@ impl NetworkRunnable for Cmd {
         client
             .verify_network_passphrase(Some(&network.network_passphrase))
             .await?;
-        Ok(client.get_remote_wasm(&contract_id).await?)
+        let data_entry = client.get_contract_data(&contract_id).await?;
+        if let ScVal::ContractInstance(contract) = &data_entry.val {
+            return match &contract.executable {
+                ContractExecutable::Wasm(hash) => {
+                    Ok(get_remote_wasm_from_hash(&client, hash).await?)
+                }
+                ContractExecutable::StellarAsset => Err(ContractIsStellarAsset()),
+            };
+        }
+        return Err(UnexpectedContractToken(data_entry));
     }
 }

cmd/soroban-cli/src/get_spec.rs

@@ -10,6 +10,7 @@ pub use soroban_spec_tools::contract as contract_spec;
 use crate::commands::global;
 use crate::config::{self, data, locator, network};
 use crate::rpc;
+use crate::utils::rpc::get_remote_wasm_from_hash;
 
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
@@ -65,7 +66,7 @@ pub async fn get_remote_contract_spec(
             if let Ok(entries) = data::read_spec(&hash_str) {
                 entries
             } else {
-                let raw_wasm = client.get_remote_wasm_from_hash(hash).await?;
+                let raw_wasm = get_remote_wasm_from_hash(&client, &hash).await?;
                 let res = contract_spec::Spec::new(&raw_wasm)?;
                 let res = res.spec;
                 if global_args.map_or(true, |a| !a.no_cache) {

cmd/soroban-cli/src/utils.rs

@@ -129,6 +129,29 @@ pub fn contract_id_hash_from_asset(
     Ok(Hash(Sha256::digest(preimage_xdr).into()))
 }
 
+pub mod rpc {
+    use soroban_env_host::xdr;
+    use soroban_rpc::{Client, Error};
+    use stellar_xdr::curr::{Hash, LedgerEntryData, LedgerKey, Limits, ReadXdr};
+
+    pub async fn get_remote_wasm_from_hash(client: &Client, hash: &Hash) -> Result<Vec<u8>, Error> {
+        let code_key = LedgerKey::ContractCode(xdr::LedgerKeyContractCode { hash: hash.clone() });
+        let contract_data = client.get_ledger_entries(&[code_key]).await?;
+        let entries = contract_data.entries.unwrap_or_default();
+        if entries.is_empty() {
+            return Err(Error::NotFound(
+                "Contract Code".to_string(),
+                hex::encode(hash),
+            ));
+        }
+        let contract_data_entry = &entries[0];
+        match LedgerEntryData::from_xdr_base64(&contract_data_entry.xdr, Limits::none())? {
+            LedgerEntryData::ContractCode(xdr::ContractCodeEntry { code, .. }) => Ok(code.into()),
+            scval => Err(Error::UnexpectedContractCodeDataType(scval)),
+        }
+    }
+}
+
 pub mod parsing {
 
     use regex::Regex;