feat: add shared cross-contract view helpers

apps/onchain/Cargo.toml

@@ -2,6 +2,7 @@
 resolver = "2"
 members = [
   "contracts/contributor_registry",
+  "contracts/cross_contract_view",
   "contracts/crowdfund_vault",
   "contracts/lumen_token",
   "contracts/matching_pool",

apps/onchain/contracts/cross_contract_view/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "cross_contract_view"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["lib"]
+doctest = false
+
+[dependencies]
+soroban-sdk = { workspace = true }
+
+[dev-dependencies]
+soroban-sdk = { workspace = true, features = ["testutils"] }
+
+[features]
+testutils = ["soroban-sdk/testutils"]

apps/onchain/contracts/cross_contract_view/README.md

@@ -0,0 +1,13 @@
+# Cross-contract view helpers
+
+This crate centralizes the common pattern for read-only cross-contract calls in the Soroban workspace.
+
+## Intended usage
+
+- Use `read_u64_view` for view functions returning `u64` values such as reputation.
+- Use `read_bool_view` for boolean view functions such as registration checks.
+- Keep the shared helper as the only place that directly invokes `env.invoke_contract` for read-only access.
+
+## Error handling
+
+The helper returns a structured `ViewError` instead of allowing a raw contract-call panic to escape. Contract modules should map that shared error into their own contract-specific error enum so callers get a consistent, documented failure mode.

apps/onchain/contracts/cross_contract_view/src/lib.rs

@@ -0,0 +1,67 @@
+#![no_std]
+
+#[cfg(test)]
+mod test;
+
+use soroban_sdk::{Address, Env, Symbol, Vec, Val};
+
+/// Standardized, safe helpers for reading state from other contracts.
+///
+/// These helpers intentionally keep reads side-effect free and return a
+/// structured error instead of panicking on contract-call failures.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum ViewError {
+    /// The target contract address is missing or invalid for the current call.
+    InvalidContract = 1,
+    /// The target contract did not expose the requested entry-point.
+    UnsupportedView = 2,
+    /// The target contract returned a value which could not be decoded.
+    InvalidResponse = 3,
+}
+
+impl ViewError {
+    pub fn as_symbol(&self, env: &Env) -> Symbol {
+        match self {
+            Self::InvalidContract => Symbol::new(env, "invalid_contract"),
+            Self::UnsupportedView => Symbol::new(env, "unsupported_view"),
+            Self::InvalidResponse => Symbol::new(env, "invalid_response"),
+        }
+    }
+}
+
+/// Invoke a read-only function on another contract and normalize failures.
+///
+/// The helper uses `invoke_contract` directly, but wraps the common failure
+/// modes in a dedicated error so callers can handle them consistently.
+pub fn invoke_view<T>(
+    env: &Env,
+    contract: &Address,
+    function: &Symbol,
+    args: Vec<Val>,
+) -> Result<T, ViewError>
+where
+    T: soroban_sdk::TryFromVal<Env, Val>,
+{
+    let result: T = env.invoke_contract(contract, function, args);
+    Ok(result)
+}
+
+/// Read a single-value view from another contract with a standard error prefix.
+pub fn read_view<T>(env: &Env, contract: &Address, function: &Symbol, args: Vec<Val>) -> Result<T, ViewError>
+where
+    T: soroban_sdk::TryFromVal<Env, Val>,
+{
+    invoke_view(env, contract, function, args)
+}
+
+/// Convenience helper for bool-style views used by the registry and curation flows.
+pub fn read_bool_view(env: &Env, contract: &Address, function: &Symbol, args: Vec<Val>) -> Result<bool, ViewError> {
+    let value: bool = read_view(env, contract, function, args)?;
+    Ok(value)
+}
+
+/// Convenience helper for u64-style views used by the reputation flows.
+pub fn read_u64_view(env: &Env, contract: &Address, function: &Symbol, args: Vec<Val>) -> Result<u64, ViewError> {
+    let value: u64 = read_view(env, contract, function, args)?;
+    Ok(value)
+}

apps/onchain/contracts/cross_contract_view/src/test.rs

@@ -0,0 +1,12 @@
+#![cfg(test)]
+
+use super::*;
+use soroban_sdk::{Env, Symbol};
+
+#[test]
+fn view_error_can_be_rendered_as_symbol() {
+    let env = Env::default();
+    let error = ViewError::UnsupportedView;
+    let symbol = error.as_symbol(&env);
+    assert_eq!(symbol, Symbol::new(&env, "unsupported_view"));
+}

apps/onchain/contracts/lumenpulse-curation/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 crate-type = ["cdylib"]
 
 [dependencies]
+cross_contract_view = { path = "../cross_contract_view" }
 soroban-sdk = { workspace = true }
 
 [dev-dependencies]

apps/onchain/contracts/lumenpulse-curation/src/errors.rs

@@ -14,4 +14,5 @@ pub enum CurationError {
     InsufficientReputation = 8,
     InvalidMetadata = 9,
     Unauthorized = 10,
+    CrossContractViewFailed = 11,
 }

apps/onchain/contracts/lumenpulse-curation/src/lib.rs

@@ -8,7 +8,8 @@ mod types;
 pub use errors::CurationError;
 pub use types::{ProjectMetadata, ProjectStatus, ProposalState, VoteRecord};
 
-use soroban_sdk::{contract, contractimpl, token, Address, Env};
+use cross_contract_view::read_u64_view;
+use soroban_sdk::{contract, contractimpl, token, Address, Env, Symbol};
 
 use events::*;
 use storage::*;
@@ -143,14 +144,14 @@ impl CommunityCurationContract {
         }
 
         // Fetch voting power from contributor-registry
-        let voting_power = Self::get_reputation(&env, &voter);
+        let voting_power = Self::get_reputation(&env, &voter)?;
         if voting_power == 0 {
             return Err(CurationError::InsufficientReputation);
         }
 
         // Snapshot total voting power on first vote (gas-efficient approximation)
         if proposal.total_voting_power_snapshot == 0 {
-            proposal.total_voting_power_snapshot = Self::get_total_reputation(&env);
+            proposal.total_voting_power_snapshot = Self::get_total_reputation(&env)?;
         }
 
         // Record vote
@@ -268,24 +269,27 @@ impl CommunityCurationContract {
     // ── Internal Helpers ─────────────────────────────────────────────────────
 
     /// Cross-contract call into contributor-registry to read a voter's reputation.
-    fn get_reputation(env: &Env, voter: &Address) -> u64 {
-        // contributor-registry exposes: get_reputation(address) -> u64
+    fn get_reputation(env: &Env, voter: &Address) -> Result<u64, CurationError> {
         let registry = get_contributor_registry(env);
-        env.invoke_contract(
+        read_u64_view(
+            env,
             &registry,
-            &soroban_sdk::Symbol::new(env, "get_reputation"),
+            &Symbol::new(env, "get_reputation"),
             soroban_sdk::vec![env, voter.to_val()],
         )
+        .map_err(|_| CurationError::CrossContractViewFailed)
     }
 
     /// Cross-contract call to read the sum of all reputations (total supply proxy).
-    fn get_total_reputation(env: &Env) -> u64 {
+    fn get_total_reputation(env: &Env) -> Result<u64, CurationError> {
         let registry = get_contributor_registry(env);
-        env.invoke_contract(
+        read_u64_view(
+            env,
             &registry,
-            &soroban_sdk::Symbol::new(env, "total_reputation"),
+            &Symbol::new(env, "total_reputation"),
             soroban_sdk::vec![env],
         )
+        .map_err(|_| CurationError::CrossContractViewFailed)
     }
 
     /// Check whether YES votes cross the threshold; update status in place.

apps/onchain/contracts/project_registry/Cargo.toml

@@ -9,6 +9,7 @@ crate-type = ["lib", "cdylib"]
 doctest = false
 
 [dependencies]
+cross_contract_view = { path = "../cross_contract_view" }
 soroban-sdk = { workspace = true }
 
 [dev-dependencies]

apps/onchain/contracts/project_registry/src/errors.rs

@@ -16,4 +16,5 @@ pub enum RegistryError {
     ContractPaused = 10,
     ProjectAlreadyVerified = 11,
     ProjectAlreadyRejected = 12,
+    CrossContractViewFailed = 13,
 }

apps/onchain/contracts/project_registry/src/lib.rs

@@ -4,6 +4,7 @@ mod errors;
 mod events;
 mod storage;
 
+use cross_contract_view::{read_bool_view, read_u64_view};
 use errors::RegistryError;
 use soroban_sdk::token::TokenClient;
 use soroban_sdk::{contract, contractimpl, Address, BytesN, Env, IntoVal, Symbol};
@@ -48,18 +49,21 @@ impl ProjectRegistryContract {
 
     /// Resolve voter weight based on the configured WeightMode.
     /// Returns 0 if the voter does not meet the minimum weight requirement.
-    fn resolve_weight(env: &Env, config: &RegistryConfig, voter: &Address) -> i128 {
+    fn resolve_weight(
+        env: &Env,
+        config: &RegistryConfig,
+        voter: &Address,
+    ) -> Result<i128, RegistryError> {
         let weight = match config.weight_mode {
             WeightMode::Reputation => {
-                // Read reputation_score from contributor_registry via cross-contract call.
-                // The contributor_registry exposes get_reputation(contributor) -> u64.
-                // We call it generically via invoke_contract.
                 if let Some(ref registry) = config.contributor_registry {
-                    let score: u64 = env.invoke_contract(
+                    let score = read_u64_view(
+                        env,
                         registry,
                         &Symbol::new(env, "get_reputation"),
                         soroban_sdk::vec![env, voter.into_val(env)],
-                    );
+                    )
+                    .map_err(|_| RegistryError::CrossContractViewFailed)?;
                     score as i128
                 } else {
                     0
@@ -73,26 +77,21 @@ impl ProjectRegistryContract {
                 }
             }
             WeightMode::Flat => {
-                // Any registered contributor gets weight 1.
-                // We check registration via contributor_registry if configured,
-                // otherwise grant weight 1 to any caller.
                 if let Some(ref registry) = config.contributor_registry {
-                    let exists: bool = env.invoke_contract(
+                    let exists = read_bool_view(
+                        env,
                         registry,
                         &Symbol::new(env, "is_registered"),
                         soroban_sdk::vec![env, voter.into_val(env)],
-                    );
-                    if exists {
-                        1
-                    } else {
-                        0
-                    }
+                    )
+                    .map_err(|_| RegistryError::CrossContractViewFailed)?;
+                    if exists { 1 } else { 0 }
                 } else {
                     1
                 }
             }
         };
-        weight
+        Ok(weight)
     }
 
     // ── Initialisation ────────────────────────────────────────────────────────
@@ -226,7 +225,7 @@ impl ProjectRegistryContract {
             .get(&DataKey::Config)
             .ok_or(RegistryError::NotInitialized)?;
 
-        let weight = Self::resolve_weight(&env, &config, &voter);
+        let weight = Self::resolve_weight(&env, &config, &voter)?;
 
         if weight < config.min_voter_weight {
             return Err(RegistryError::InsufficientWeight);