Add extension field to get ahead of potential unupgradable change

locked-nft/contracts/NFTLocker.cdc

@@ -47,6 +47,7 @@ pub contract NFTLocker {
         pub let lockedUntil: UInt64
         pub let duration: UInt64
         pub let nftType: Type
+        pub let extension: {String: AnyStruct}
 
         init (id: UInt64, owner: Address, duration: UInt64, nftType: Type) {
             if let lockedToken = (NFTLocker.lockedTokens[nftType]!)[id] {
@@ -56,19 +57,21 @@ pub contract NFTLocker {
                 self.lockedUntil = lockedToken.lockedUntil
                 self.duration = lockedToken.duration
                 self.nftType = lockedToken.nftType
+                self.extension = lockedToken.extension
             } else {
                 self.id = id
                 self.owner = owner
                 self.lockedAt = UInt64(getCurrentBlock().timestamp)
                 self.lockedUntil = self.lockedAt + duration
                 self.duration = duration
                 self.nftType = nftType
+                self.extension = {}
             }
         }
     }
 
     pub fun getNFTLockerDetails(id: UInt64, nftType: Type): NFTLocker.LockedData? {
-        return (NFTLocker.lockedTokens[nftType]!)[id]!
+        return (NFTLocker.lockedTokens[nftType]!)[id]
     }
 
     /// Determine if NFT can be unlocked

locked-nft/lib/go/test/lockednft_test.go

@@ -76,6 +76,13 @@ func testLockNFT(
 	)
 
 	assert.Equal(t, lockedAt+duration, lockedUntil)
+	lockedData := getLockedTokenData(
+		t,
+		b,
+		contracts,
+		exampleNftID,
+	)
+	assert.Equal(t, lockedData.LockedUntil, lockedUntil)
 }
 
 func TestReLockNFT(t *testing.T) {

locked-nft/lib/go/test/templates.go

@@ -35,8 +35,8 @@ const (
 	// MetadataViews
 	MetadataViewsContractsBaseURL = "https://raw.githubusercontent.com/onflow/flow-nft/master/contracts/"
 	MetadataViewsInterfaceFile    = "MetadataViews.cdc"
-	MetadataFTReplaceAddress      = `"./utility/FungibleToken.cdc"`
-	MetadataNFTReplaceAddress     = `"./NonFungibleToken.cdc"`
+	MetadataFTReplaceAddress      = `"FungibleToken"`
+	MetadataNFTReplaceAddress     = `"NonFungibleToken"`
 
 	// NFTLocker
 	GetLockedTokenByIDScriptPath = ScriptsRootPath + "/get_locked_token.cdc"

locked-nft/lib/go/test/types.go

@@ -5,18 +5,21 @@ import (
 )
 
 type LockedData struct {
+	ID          uint64
 	Owner       string
 	LockedAt    uint64
 	LockedUntil uint64
 	nftType     string
 }
 
 func parseLockedData(value cadence.Value) LockedData {
-	fields := value.(cadence.Struct).Fields
+	fields := value.(cadence.Optional).Value.(cadence.Struct).Fields
+
 	return LockedData{
-		fields[0].ToGoValue().(string),
-		fields[1].ToGoValue().(uint64),
+		fields[0].ToGoValue().(uint64),
+		fields[1].(cadence.Address).String(),
 		fields[2].ToGoValue().(uint64),
-		fields[3].ToGoValue().(string),
+		fields[3].ToGoValue().(uint64),
+		fields[5].(cadence.TypeValue).StaticType.ID(),
 	}
 }

locked-nft/scripts/get_locked_token.cdc

@@ -1,5 +1,6 @@
 import NFTLocker from "../contracts/NFTLocker.cdc"
+import ExampleNFT from 0xEXAMPLENFTADDRESS
 
-pub fun main(id: UInt64, nftType: Type): NFTLocker.LockedData? {
-    return NFTLocker.getNFTLockerDetails(id: id, nftType: nftType)
+pub fun main(id: UInt64): NFTLocker.LockedData? {
+    return NFTLocker.getNFTLockerDetails(id: id, nftType: Type<@ExampleNFT.NFT>())
 }