read-msg recoverable under some key

CHANGELOG.md

@@ -1,3 +1,10 @@
+4.7.0
+---
+* `read-*` functions are now recoverable if the key doesn't exist. That is, a call such as `(read-string 'key)` is recoverable
+if `'key` does not exist in the data payload by surrounding it with `try`. As an example, `(try "string if key isn't present" (read-string "key"))`. This applies to
+`read-integer`, `read-string`, `read-decimal`, `read-keyset` and `read-msg` (as long as `read-msg` has a key supplied as an argument).
+
+
 4.6.0
 ---
 * Add `DisablePact46` execution flag (#1138)

src/Pact/Native/Internal.hs

@@ -75,7 +75,7 @@ colsToList argFail _ = argFail
 parseMsgKey :: (FromJSON t) => FunApp -> String -> Text -> Eval e t
 parseMsgKey f s t = parseMsgKey' f s (Just t)
 
-parseMsgKey' :: (FromJSON t) => FunApp -> String -> (Maybe Text) -> Eval e t
+parseMsgKey' :: (FromJSON t) => FunApp -> String -> Maybe Text -> Eval e t
 parseMsgKey' i msg key = do
   b <- view eeMsgBody
   let go v = case fromJSON v of
@@ -85,7 +85,10 @@ parseMsgKey' i msg key = do
   case key of
     Nothing -> go b
     Just k -> case preview (A.key k) b of
-      Nothing -> evalError' i $ "No such key in message: " <> pretty k
+      Nothing ->
+        ifExecutionFlagSet FlagDisablePact47
+          (evalError' i $ "No such key in message: " <> pretty k)
+          (failTx' i $ "No such key in message: " <> pretty k)
       Just v -> go v
 
 

tests/pact/try.repl

@@ -131,3 +131,28 @@
 ;; require-cap works in enforce-one post-fork
 (expect "require-cap works sin enforce-one" true (enforce-cap))
 (commit-tx)
+
+; read-* functions made recoverable
+
+(begin-tx)
+(env-data {})
+(env-exec-config ["DisablePact47"])
+(expect-failure "read-integer fails on non-existent key" (try 1 (read-integer "somekey")))
+(expect-failure "read-string fails on non-existent key" (try 1 (read-string "somekey")))
+(expect-failure "read-keyset fails on non-existent key" (try 1 (read-keyset "somekey")))
+(expect-failure "read-decimal fails on non-existent key" (try 1 (read-decimal "somekey")))
+(expect-failure "read-msg fails on non-existent key" (try 1 (read-msg "somekey")))
+(commit-tx)
+
+; Post-fork, they are recoverable
+(begin-tx)
+
+(env-data {})
+(env-exec-config [])
+(expect "read-integer fails on non-existent key but is recoverable" 1 (try 1 (read-integer "somekey")))
+(expect "read-string fails on non-existent key but is recoverable" 1 (try 1 (read-string "somekey")))
+(expect "read-keyset fails on non-existent key but is recoverable" 1 (try 1 (read-keyset "somekey")))
+(expect "read-decimal fails on non-existent key but is recoverable" 1 (try 1 (read-decimal "somekey")))
+(expect "read-msg fails on non-existent key but is recoverable" 1 (try 1 (read-msg "somekey")))
+(commit-tx)
+