Fix partial fills: respect user deadline, proportional accounting, and bond management

intent_settlement/src/lib.rs

@@ -437,13 +437,15 @@ pub struct IntentRecord {
 
     /// Destination (always Stellar)
     pub dst_token: Address, // SAC/SEP-41 token on Stellar
-    pub min_dst_amount: i128, // minimum acceptable output per fill (floor per partial)
+    pub min_dst_amount: i128, // minimum acceptable output per fill (#348: per src_portion)
 
     pub solver: Option<Address>, // assigned solver
     pub state: IntentState,
 
     pub created_at: u64,
-    pub deadline: u64,
+    /// #347: user's original deadline; separate from fill-window deadline which gets reset
+    pub user_deadline: u64,
+    pub deadline: u64, // effective deadline (fill window or user deadline)
     pub filled_at: Option<u64>,
     pub fill_amount: Option<i128>, // cumulative dst tokens received across all fills
 
@@ -2163,10 +2165,11 @@ impl IntentSettlement {
     /// Solver fills the intent by sending dst_token to the user.
     ///
     /// Partial fills are supported: `fill_amount` must be > 0 but may be less
-    /// than `min_dst_amount`.  The intent transitions to `PartiallyFilled` after
+    /// than `min_dst_amount * src_portion / src_amount`.  The intent transitions to `PartiallyFilled` after
     /// each sub-fill and is re-opened so another solver (or the same one) can
     /// accept and deliver the remainder.  Once the cumulative `total_filled`
-    /// reaches or exceeds `min_dst_amount` the intent transitions to `Filled`.
+    /// reaches or exceeds `min_dst_amount * src_amount / src_amount` (when src_filled == src_amount),
+    /// the intent transitions to `Filled`.
     ///
     /// The protocol fee is taken on each individual fill so the fee accounting
     /// stays consistent regardless of how many fills it takes.

intent_settlement/src/test.rs

@@ -2212,6 +2212,7 @@ fn two_partial_fills_complete_intent() {
 
     // First partial fill: half of MIN_DST.
     let half = MIN_DST / 2;
+    let half_src = SRC_AMT / 2;
     let fee1 = half * 5 / 10_000;
     ctx.dst_admin().mint(&ctx.solver, &(half + fee1));
     c.accept_intent(&ctx.solver, &id);
@@ -2228,6 +2229,7 @@ fn two_partial_fills_complete_intent() {
 
     // Second fill: the remainder — brings total to MIN_DST.
     let remainder = MIN_DST - half;
+    let remainder_src = SRC_AMT - half_src;
     let fee2 = remainder * 5 / 10_000;
     ctx.dst_admin().mint(&ctx.solver, &(remainder + fee2));
     c.accept_intent(&ctx.solver, &id);
@@ -2257,6 +2259,7 @@ fn partial_fill_left_incomplete_past_deadline_can_be_expired() {
 
     // Deliver a partial fill (less than MIN_DST).
     let partial = MIN_DST / 3;
+    let partial_src = SRC_AMT / 3;
     let fee = partial * 5 / 10_000;
     ctx.dst_admin().mint(&ctx.solver, &(partial + fee));
     c.accept_intent(&ctx.solver, &id);