Update EVM util scripts & transactions

cadence/scripts/evm/call.cdc

@@ -36,5 +36,9 @@ access(all) fun main(
         value: EVM.Balance(attoflow: 0)
     )
 
-    return EVM.decodeABI(types: getTypeArray(typeIdentifiers), data: evmResult.data)
+    if typeIdentifiers.length == 0 {
+        return []
+    } else {
+        return EVM.decodeABI(types: getTypeArray(typeIdentifiers), data: evmResult.data)
+    }
 }

cadence/scripts/evm/get_evm_address_string.cdc

@@ -3,13 +3,9 @@ import "EVM"
 /// Returns the hex encoded address of the COA in the given Flow address
 ///
 access(all) fun main(flowAddress: Address): String? {
-    if let address: EVM.EVMAddress = getAuthAccount<auth(BorrowValue) &Account>(flowAddress)
-        .storage.borrow<&EVM.CadenceOwnedAccount>(from: /storage/evm)?.address() {
-        let bytes: [UInt8] = []
-        for byte in address.bytes {
-            bytes.append(byte)
-        }
-        return String.encodeHex(bytes)
-    }
-    return nil
+    return getAuthAccount<auth(BorrowValue) &Account>(flowAddress)
+        .storage.borrow<&EVM.CadenceOwnedAccount>(from: /storage/evm)
+        ?.address()
+        ?.toString()
+        ?? nil
 }

cadence/scripts/evm/get_evm_address_string_from_bytes.cdc

@@ -5,7 +5,5 @@ import "EVM"
 access(all) fun main(bytes: [UInt8]): String? {
     let constBytes = bytes.toConstantSized<[UInt8; 20]>()
         ?? panic("Problem converting provided EVMAddress compatible byte array - check byte array contains 20 bytes")
-    return EVM.EVMAddress(
-        bytes: constBytes
-    )
+    return EVM.EVMAddress(bytes: constBytes).toString()
 }

cadence/transactions/evm/create_account.cdc

@@ -1,31 +1,62 @@
-import "EVM"
+import "Burner"
 import "FungibleToken"
 import "FlowToken"
+import "EVM"
 
 /// Creates a COA and saves it in the signer's Flow account & passing the given value of Flow into FlowEVM
 ///
 transaction(amount: UFix64) {
-    let sentVault: @FlowToken.Vault
-    let auth: auth(IssueStorageCapabilityController, IssueStorageCapabilityController, PublishCapability, SaveValue, UnpublishCapability) &Account
+    let fundingVault: @FlowToken.Vault?
+    let coa: &EVM.CadenceOwnedAccount
+
+    prepare(signer: auth(BorrowValue, SaveValue, IssueStorageCapabilityController, PublishCapability) &Account) {
+        /* --- Configure COA --- */
+        //
+        // Ensure there is not yet a CadenceOwnedAccount in the standard path
+        let coaPath = /storage/evm
+        if signer.storage.type(at: coaPath) != nil {
+            panic(
+                "Object already exists in signer's account at path=".concat(coaPath.toString())
+                .concat(". Make sure the signing account does not already have a CadenceOwnedAccount.")
+            )
+        }
+        // COA not found in standard path, create and publish a public **unentitled** capability
+        signer.storage.save(<-EVM.createCadenceOwnedAccount(), to: coaPath)
+        let coaCapability = signer.capabilities.storage.issue<&EVM.CadenceOwnedAccount>(coaPath)
+        signer.capabilities.publish(coaCapability, at: /public/evm)
 
-    prepare(signer: auth(BorrowValue, IssueStorageCapabilityController, PublishCapability, SaveValue, UnpublishCapability) &Account) {
-        let vaultRef = signer.storage.borrow<auth(FungibleToken.Withdraw) &FlowToken.Vault>(
-                from: /storage/flowTokenVault
-            ) ?? panic("Could not borrow reference to the owner's Vault!")
+        // Borrow the CadenceOwnedAccount reference
+        self.coa = signer.storage.borrow<&EVM.CadenceOwnedAccount>(
+                from: coaPath
+            ) ?? panic(
+                "Could not find CadenceOwnedAccount (COA) in signer's account at path=".concat(coaPath.toString())
+                .concat(". Make sure the signing account has initialized a COA at the expected path.")
+            )
 
-        self.sentVault <- vaultRef.withdraw(amount: amount) as! @FlowToken.Vault
-        self.auth = signer
+        /* --- Assign fundingVault --- */
+        //
+        if amount > 0.0 {
+            // Reference the signer's FLOW vault & withdraw the funding amount
+            let vault = signer.storage.borrow<auth(FungibleToken.Withdraw) &FlowToken.Vault>(from: /storage/flowTokenVault)
+                ?? panic("Could not borrow a reference to the signer's FLOW vault from path=/storage/flowTokenVault")
+            self.fundingVault <- vault.withdraw(amount: amount) as! @FlowToken.Vault
+        } else {
+            // No funding requested, so no need to withdraw from the vault
+            self.fundingVault <- nil
+        }
     }
 
-    execute {
-        let coa <- EVM.createCadenceOwnedAccount()
-        coa.deposit(from: <-self.sentVault)
+    pre {
+        self.fundingVault == nil || self.fundingVault?.balance ?? 0.0 == amount:
+            "Mismatched funding vault acquired given requested amount=".concat(amount.toString())
+    }
 
-        let storagePath = StoragePath(identifier: "evm")!
-        let publicPath = PublicPath(identifier: "evm")!
-        self.auth.storage.save<@EVM.CadenceOwnedAccount>(<-coa, to: storagePath)
-        let addressableCap = self.auth.capabilities.storage.issue<&EVM.CadenceOwnedAccount>(storagePath)
-        self.auth.capabilities.unpublish(publicPath)
-        self.auth.capabilities.publish(addressableCap, at: publicPath)
+    execute {
+        // Fund if necessary
+        if self.fundingVault != nil || self.fundingVault?.balance ?? 0.0 > 0.0 {
+            self.coa.deposit(from: <-self.fundingVault!)
+        } else {
+            Burner.burn(<-self.fundingVault)
+        }
     }
 }

cadence/transactions/evm/destroy_coa.cdc

@@ -1,9 +1,21 @@
+import "Burner"
 import "EVM"
 
-/// !!! CAUTION: Destroys the COA in the signer's account !!! 
+/// !!! CAUTION: Destroys the COA in the signer's account !!!
 ///
 transaction {
-    prepare(signer: auth(LoadValue) &Account) {
-        destroy signer.storage.load<@EVM.CadenceOwnedAccount>(from: /storage/evm)!
+    prepare(signer: auth(LoadValue, StorageCapabilities, UnpublishCapability) &Account) {
+        // Unpublish the COA capability
+        signer.capabilities.unpublish(/public/evm)
+
+        // Delete all COA capabilities
+        signer.capabilities.storage.forEachController(forPath: /storage/evm, fun (controller: &StorageCapabilityController): Bool {
+            controller.delete()
+            return true
+        })
+
+        // Destroy the COA
+        let coa <- signer.storage.load<@EVM.CadenceOwnedAccount>(from: /storage/evm)!
+        Burner.burn(<-coa)
     }
 }

cadence/transactions/evm/withdraw.cdc

@@ -28,6 +28,6 @@ transaction(amount: UFix64) {
     }
 
     post {
-        self.vault.balance == self.preBalance + amount: "Problem transfering Flow between environments!"
+        self.vault.balance == self.preBalance + amount: "Problem transferring Flow between environments!"
     }
 }

flow.json

@@ -260,7 +260,7 @@
 		},
 		"EVM": {
 			"source": "mainnet://e467b9dd11fa00df.EVM",
-			"hash": "1b1f3fe59d964b8afde33d3150ab89f257373aa253ae412c8b02fb176dd03698",
+			"hash": "5c69921fa06088b477e2758e122636b39d3d3eb5316807c206c5680d9ac74c7e",
 			"aliases": {
 				"emulator": "f8d6e0586b0a20c7",
 				"mainnet": "e467b9dd11fa00df",
@@ -287,7 +287,7 @@
 		},
 		"FungibleToken": {
 			"source": "mainnet://f233dcee88fe0abe.FungibleToken",
-			"hash": "1410889b47fef8b02f6867eef3d67a75288a56a651b67a7e815ce273ad301cff",
+			"hash": "050328d01c6cde307fbe14960632666848d9b7ea4fef03ca8c0bbfb0f2884068",
 			"aliases": {
 				"emulator": "ee82856bf20e2aa6",
 				"mainnet": "f233dcee88fe0abe",
@@ -296,7 +296,7 @@
 		},
 		"FungibleTokenMetadataViews": {
 			"source": "mainnet://f233dcee88fe0abe.FungibleTokenMetadataViews",
-			"hash": "294ada6a3df68757fcac4d794f62307c2ea4fe49c93f67e3771d3c6d8377dd47",
+			"hash": "dff704a6e3da83997ed48bcd244aaa3eac0733156759a37c76a58ab08863016a",
 			"aliases": {
 				"emulator": "ee82856bf20e2aa6",
 				"mainnet": "f233dcee88fe0abe",
@@ -305,7 +305,7 @@
 		},
 		"MetadataViews": {
 			"source": "mainnet://1d7e57aa55817448.MetadataViews",
-			"hash": "be26ea7959d7cbc06ac69fe00926b812c4da67984ea2d1bde1029141ae091378",
+			"hash": "10a239cc26e825077de6c8b424409ae173e78e8391df62750b6ba19ffd048f51",
 			"aliases": {
 				"emulator": "f8d6e0586b0a20c7",
 				"mainnet": "1d7e57aa55817448",
@@ -314,7 +314,7 @@
 		},
 		"NonFungibleToken": {
 			"source": "mainnet://1d7e57aa55817448.NonFungibleToken",
-			"hash": "49a58b950afdaf0728fdb7d4eb47cf4f2ec3077d655f274b7fdeb504c742f528",
+			"hash": "b63f10e00d1a814492822652dac7c0574428a200e4c26cb3c832c4829e2778f0",
 			"aliases": {
 				"emulator": "f8d6e0586b0a20c7",
 				"mainnet": "1d7e57aa55817448",