Fix/bound pause reason

apexchainx_calculator/src/lib.rs

@@ -55,6 +55,9 @@ const PAUSED_KEY: Symbol = symbol_short!("PAUSED");
 /// Pause metadata (reason, timestamp, caller). (#66)
 const PAUSE_INFO_KEY: Symbol = symbol_short!("PAUSEINF");
 
+/// Maximum length (in bytes) for the pause reason string. (#68)
+const MAX_REASON_LEN: usize = 256;
+
 /// Cumulative SLA statistics (SLAStats struct). (#29)
 const STATS_KEY: Symbol = symbol_short!("STATS");
 
@@ -247,6 +250,8 @@ pub enum SLAError {
     InvalidPenaltyAmount = 14,
     /// Computed reward amount is invalid (e.g., zero or negative). (SC-W5-046)
     InvalidRewardAmount = 15,
+    /// Input parameter violates documented constraints (e.g., reason too long). (#68)
+    InvalidInput = 16,
 }
 
 // -----------------------------------------------------------------------
@@ -782,6 +787,10 @@ impl SLACalculatorContract {
         Self::check_version(&env)?;
         Self::require_admin(&env, &caller)?;
 
+        if reason.len() > MAX_REASON_LEN as u32 {
+            return Err(SLAError::InvalidInput);
+        }
+
         let paused_at = env.ledger().timestamp();
         env.storage().instance().set(&PAUSED_KEY, &true);
         env.storage().instance().set(

apexchainx_calculator/src/tests.rs

@@ -1918,6 +1918,15 @@ fn test_pause_stores_reason_and_timestamp() {
     let _ = info.paused_at;
 }
 
+#[test]
+#[should_panic(expected = "#16")]
+fn test_pause_rejects_long_reason() {
+    let (env, client, actors) = setup();
+    // 257-byte reason exceeds MAX_REASON_LEN (256)
+    let long_reason = soroban_sdk::String::from_str(&env, &"A".repeat(257));
+    client.pause(&actors.admin, &long_reason);
+}
+
 #[test]
 fn test_unpause_clears_pause_info() {
     let (env, client, actors) = setup();