rename 'missingCoins' field to 'shortfall' in the MA selection change…

… error
cardano-foundation · Jan 27, 2021 · b34a575 · b34a575
1 parent 2650cff
commit b34a575
Show file tree

Hide file tree

Showing 3 changed files with 10 additions and 10 deletions.
diff --git a/lib/core/src/Cardano/Wallet/Api/Server.hs b/lib/core/src/Cardano/Wallet/Api/Server.hs
@@ -2785,7 +2785,7 @@ instance LiftHandler ErrSelectAssets where
                         [ "I am unable to finalize the transaction as there are "
                         , "not enough Ada I can use to pay for either fees, or "
                         , "minimum Ada value in change outputs. I need about "
-                        , pretty (missingCoins e), " Ada to proceed; try "
+                        , pretty (shortfall e), " Ada to proceed; try "
                         , "increasing your wallet balance as such, or try "
                         , "sending a different, smaller payment."
                         ]

diff --git a/lib/core/src/Cardano/Wallet/Primitive/CoinSelection/MA/RoundRobin.hs b/lib/core/src/Cardano/Wallet/Primitive/CoinSelection/MA/RoundRobin.hs
@@ -231,9 +231,9 @@ buildSelectionResult
     -> Builder
 buildSelectionResult changeF s@SelectionResult{inputsSelected,extraCoinSource} =
     mconcat
-        [ nameF "inputs selected"  (inputsF inputsSelected)
+        [ nameF "inputs selected" (inputsF inputsSelected)
         , nameF "extra coin input" (build extraCoinSource)
-        , nameF "outputs covered"  (build $ outputsCovered s)
+        , nameF "outputs covered" (build $ outputsCovered s)
         , nameF "change generated" (changeF $ changeGenerated s)
         , nameF "size utxo remaining" (build $ UTxOIndex.size $ utxoRemaining s)
         ]
@@ -318,7 +318,7 @@ data UnableToConstructChangeError = UnableToConstructChangeError
         :: !Coin
         -- ^ The minimal required cost needed for the transaction to be
         -- considered valid. This does not include min Ada values.
-    , missingCoins
+    , shortfall
         :: !Coin
         -- ^ The additional coin quantity that would be required to cover the
         -- selection cost and minimum coin quantity of each change output.
@@ -588,10 +588,10 @@ runSelection limit mExtraCoinSource available minimumBalance =
         , leftover = available
         }
 
-    -- NOTE: We run the 'coinSelector' last, because we know that there are
-    -- necessarily coins in all inputs. Therefore, after having ran the other
-    -- selectors, we may already have covered for coins and need not to select
-    -- extra inputs.
+    -- NOTE: We run the 'coinSelector' last, because we know that every input
+    -- necessarily has a non-zero ada amount. By running the other selectors
+    -- first, we increase the probability that the coin selector will be able
+    -- to terminate without needing to select an additional coin.
     selectors :: [SelectionState -> m (Maybe SelectionState)]
     selectors =
         reverse (coinSelector : fmap assetSelector minimumAssetQuantities)
@@ -839,7 +839,7 @@ makeChange minCoinValueFor requiredCost mExtraCoinSource inputBundles outputBund
     changeError excessCoin change =
         UnableToConstructChangeError
             { requiredCost
-            , missingCoins =
+            , shortfall =
                 -- This conversion is safe because we know that the distance is
                 -- small-ish. If it wasn't, we would have have enough coins to
                 -- construct the change.

diff --git a/lib/core/test/unit/Cardano/Wallet/Primitive/CoinSelection/MA/RoundRobinSpec.hs b/lib/core/test/unit/Cardano/Wallet/Primitive/CoinSelection/MA/RoundRobinSpec.hs
@@ -612,7 +612,7 @@ prop_performSelection minCoinValueFor costFor (Blind criteria) coverage =
 
     onUnableToConstructChange e = do
         monitor $ counterexample $ show e
-        assert (missingCoins e > Coin 0)
+        assert (shortfall e > Coin 0)
         let criteria' = criteria { selectionLimit = NoLimit }
         run (performSelection noMinCoin (const noCost) criteria') >>= \case
             Left e' -> do