From dc378a562de6abcd87f4b0fc5bbcb2f5c0bd2d11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Wed, 27 Dec 2017 23:00:11 +0200
Subject: [PATCH] accounts/abi: handle named ouputs prefixed with underscores

---
 accounts/abi/argument.go       |  3 ++-
 accounts/abi/bind/bind.go      |  6 +++++-
 accounts/abi/bind/bind_test.go | 30 ++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/accounts/abi/argument.go b/accounts/abi/argument.go
index ad17fbf2b1..4a5d03186e 100644
--- a/accounts/abi/argument.go
+++ b/accounts/abi/argument.go
@@ -126,7 +126,8 @@ func (arguments Arguments) unpackTuple(v interface{}, output []byte) error {
 			for j := 0; j < typ.NumField(); j++ {
 				field := typ.Field(j)
 				// TODO read tags: `abi:"fieldName"`
-				if field.Name == strings.ToUpper(arg.Name[:1])+arg.Name[1:] {
+				trimmed := strings.TrimLeft(arg.Name, "_")
+				if field.Name == strings.ToUpper(trimmed[:1])+trimmed[1:] {
 					if err := set(value.Field(j), reflectValue, arg); err != nil {
 						return err
 					}
diff --git a/accounts/abi/bind/bind.go b/accounts/abi/bind/bind.go
index 4dce79b779..5d2b61b870 100644
--- a/accounts/abi/bind/bind.go
+++ b/accounts/abi/bind/bind.go
@@ -304,8 +304,12 @@ var methodNormalizer = map[Lang]func(string) string{
 	LangJava: decapitalise,
 }
 
-// capitalise makes the first character of a string upper case.
+// capitalise makes the first character of a string upper case, also removing any
+// prefixing underscores from the variable names.
 func capitalise(input string) string {
+	for len(input) > 0 && input[0] == '_' {
+		input = input[1:]
+	}
 	return strings.ToUpper(input[:1]) + input[1:]
 }
 
diff --git a/accounts/abi/bind/bind_test.go b/accounts/abi/bind/bind_test.go
index 43ed53b922..b1b2b22c17 100644
--- a/accounts/abi/bind/bind_test.go
+++ b/accounts/abi/bind/bind_test.go
@@ -447,6 +447,36 @@ var bindTests = []struct {
 			}
 		`,
 	},
+	{
+		`Underscorer`,
+		`
+			contract Underscorer {
+			function UnderscoredOutput() constant returns (int _int, string _string) {
+			    return (314, "pi");
+				}
+			}
+		`, `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`,
+		`[{"constant": true,"inputs": [],"name": "UnderscoredOutput","outputs": [{"name": "_int","type": "int256"},{"name": "_string","type": "string"}],"payable": false,"stateMutability": "view","type": "function"}]`,
+		`
+			// Generate a new random account and a funded simulator
+			key, _ := crypto.GenerateKey()
+			auth := bind.NewKeyedTransactor(key)
+			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000)}})
+
+			// Deploy a underscorer tester contract and execute a structured call on it
+			_, _, underscorer, err := DeployUnderscorer(auth, sim)
+			if err != nil {
+				t.Fatalf("Failed to deploy underscorer contract: %v", err)
+			}
+			sim.Commit()
+
+			if res, err := underscorer.UnderscoredOutput(nil); err != nil {
+				t.Errorf("Failed to call constant function: %v", err)
+			} else if res.Int.Cmp(big.NewInt(314)) != 0 || res.String != "pi" {
+				t.Errorf("Invalid result, want: {314, \"pi\"}, got: %+v", res)
+			}
+		`,
+	},
 }
 
 // Tests that packages generated by the binder can be successfully compiled and