[WA-37]: Append method id to duplicate function names (#9)

Sources/BivrostKit/Generating/ContractTemplateModel.swift

@@ -34,22 +34,39 @@ struct ContractTemplateModel {
     init(contract: Contract) {
         name = contract.name.asTypeName
 
-        functions = contract.elements.flatMap { element -> ContractTemplateModel.Function? in
-            guard case .function(let object) = element else { return nil }
-
-            let functionName = object.name.asTypeName
-            let functionMethodId = object.methodId
-
-            let inputString = tupleString(for: object.inputs)
-            let outputString = tupleString(for: object.outputs)
-
-            let encodeArgumentsString = encodeArguments(for: object.inputs)
-            let decodeReturnTypesArray = decodeTypes(for: object.outputs)
-            let decodeReturnReturnValueString = decodeReturnReturnValue(for: decodeReturnTypesArray)
-            let decodeArgumentsTypesArray = decodeTypes(for: object.inputs)
-            let decodeArgumentsReturnValueString = decodeArgumentsReturnValue(for: decodeArgumentsTypesArray)
-
-            return ContractTemplateModel.Function(name: functionName, methodId: functionMethodId, input: inputString, output: outputString, encodeArguments: encodeArgumentsString, decodeReturnReturnValue: decodeReturnReturnValueString, decodeReturnTypes: decodeReturnTypesArray, decodeArgumentsReturnValue: decodeArgumentsReturnValueString, decodeArgumentsTypes: decodeArgumentsTypesArray)
+        // In code generation function names are used for struct names.
+        // This means they have to be unique, so filter for duplicate entries
+        // and append the method id on all of them (group by name, mark non-uniques
+        // and treat them accordingly)
+        functions = contract.elements
+            .flatMap {
+                guard case .function(let object) = $0 else { return nil }
+                return object
+            }
+            .group(by: { $0.name })
+            .flatMap { entry -> [(Contract.Element.Function, Bool)] in
+                // flatMap grouped array (dictionary) into an array of
+                // (object, useMethodId) tuples
+                return entry.value.map { ($0, entry.value.count > 1) }
+            }
+            .flatMap { pair -> ContractTemplateModel.Function? in
+                let object = pair.0
+                let shouldAppendMethodId = pair.1
+
+                let functionMethodId = object.methodId
+                let functionName = object.name.asTypeName
+                let preparedFunctionName = shouldAppendMethodId ? "\(functionName)_\(object.methodId)" : functionName
+
+                let inputString = tupleString(for: object.inputs)
+                let outputString = tupleString(for: object.outputs)
+
+                let encodeArgumentsString = encodeArguments(for: object.inputs)
+                let decodeReturnTypesArray = decodeTypes(for: object.outputs)
+                let decodeReturnReturnValueString = decodeReturnReturnValue(for: decodeReturnTypesArray)
+                let decodeArgumentsTypesArray = decodeTypes(for: object.inputs)
+                let decodeArgumentsReturnValueString = decodeArgumentsReturnValue(for: decodeArgumentsTypesArray)
+
+                return ContractTemplateModel.Function(name: preparedFunctionName, methodId: functionMethodId, input: inputString, output: outputString, encodeArguments: encodeArgumentsString, decodeReturnReturnValue: decodeReturnReturnValueString, decodeReturnTypes: decodeReturnTypesArray, decodeArgumentsReturnValue: decodeArgumentsReturnValueString, decodeArgumentsTypes: decodeArgumentsTypesArray)
         }
     }
 }

Sources/BivrostKit/Generating/SequenceExtension.swift

@@ -0,0 +1,21 @@
+//
+//  SequenceExtension.swift
+//  BivrostKit
+//
+//  Created by Luis Reisewitz on 23.10.17.
+//
+
+// From https://stackoverflow.com/a/31220067/972993
+
+public extension Sequence {
+    func group<U: Hashable>(by key: (Iterator.Element) -> U) -> [U:[Iterator.Element]] {
+        var categories: [U: [Iterator.Element]] = [:]
+        for element in self {
+            let key = key(element)
+            if case nil = categories[key]?.append(element) {
+                categories[key] = [element]
+            }
+        }
+        return categories
+    }
+}

Tests/BivrostKitTests/Assets.swift

@@ -7,6 +7,49 @@
 //
 
 struct Assets {
+    static let duplicateMethodJson = """
+    {
+        "contract_name": "DuplicateMethod",
+        "abi": [
+          {
+            "constant": true,
+            "inputs": [],
+            "name": "totalSupply",
+            "outputs": [
+              {
+                "name": "",
+                "type": "uint256"
+              }
+            ],
+            "payable": false,
+            "type": "function"
+          },
+          {
+            "constant": true,
+            "inputs": [
+              {
+                "name": "spender",
+                "type": "address"
+              },
+              {
+                "name": "value",
+                "type": "uint256"
+              }
+            ],
+            "name": "totalSupply",
+            "outputs": [
+              {
+                "name": "",
+                "type": "uint256"
+              }
+            ],
+            "payable": false,
+            "type": "function"
+          }
+        ]
+    }
+
+    """
     static let multiSigWalletJson = """
         {
           "contract_name": "MultiSigWalletWithDailyLimit",

Tests/BivrostKitTests/ContractTemplateModelSpec.swift

@@ -0,0 +1,42 @@
+//
+//  ContractTemplateModelSpec.swift
+//  BivrostKitTests
+//
+//  Created by Luis Reisewitz on 23.10.17.
+//  Copyright © 2017 Gnosis. All rights reserved.
+//
+
+
+import Foundation
+import Quick
+import Nimble
+@testable import BivrostKit
+
+class ContractTemplateModelSpec: QuickSpec {
+    override func spec() {
+        describe("ContractTemplateModel") {
+            it("should append method ids to generated function names in case of duplicates") {
+                let json = jsonDict(from: Assets.duplicateMethodJson)
+                let contract = try! ContractParser.parseContract(from: json)
+                let model = ContractTemplateModel(contract: contract)
+                model.functions.forEach {
+                    expect($0.name).to(contain($0.methodId))
+                }
+            }
+
+            it("should not append method ids to generated function names in case of no duplicates") {
+                let json = jsonDict(from: Assets.standardTokenJson)
+                let contract = try! ContractParser.parseContract(from: json)
+                let model = ContractTemplateModel(contract: contract)
+                model.functions.forEach {
+                    expect($0.name).toNot(contain($0.methodId))
+                }
+            }
+        }
+    }
+
+}
+
+fileprivate func jsonDict(from jsonString: String) -> [String: Any] {
+    return try! JSONSerialization.jsonObject(with: jsonString.data(using: .utf8)!, options: []) as! [String: Any]
+}