From aed5f2e44a603a8227b232a71d077f351e2bac0f Mon Sep 17 00:00:00 2001
From: Richard Schneider <makaretu@gmail.com>
Date: Thu, 29 Nov 2018 15:08:40 +1300
Subject: [PATCH] fix(MultiAddress): allow empty MultiAddress, fixes #69

BREAKING CHANGE

MultiAddress(byte) and MultiAddress(string) do not throw on empty input.  They
simply create an empty Protocols.
---
 src/MultiAddress.cs      |  5 ++++-
 test/MultiAddressTest.cs | 18 ++++--------------
 2 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/src/MultiAddress.cs b/src/MultiAddress.cs
index 1e258a3..92666ea 100644
--- a/src/MultiAddress.cs
+++ b/src/MultiAddress.cs
@@ -51,7 +51,7 @@ public MultiAddress()
         public MultiAddress(string s) : this()
         {
             if (string.IsNullOrWhiteSpace(s))
-                throw new ArgumentNullException("s");
+                return;
 
             Read(new StringReader(s));
         }
@@ -104,6 +104,9 @@ public MultiAddress Clone()
         public MultiAddress(byte[] buffer)
             : this()
         {
+            if (buffer == null || buffer.Length == 0)
+                return;
+
             Read(new MemoryStream(buffer, false));
         }
 
diff --git a/test/MultiAddressTest.cs b/test/MultiAddressTest.cs
index dda28cf..f2a090a 100644
--- a/test/MultiAddressTest.cs
+++ b/test/MultiAddressTest.cs
@@ -27,9 +27,9 @@ public void Parsing()
             Assert.AreEqual("ipfs", a.Protocols[2].Name);
             Assert.AreEqual("QmVcSqVEsvm5RR9mBLjwpb2XjFVn5bPdPL69mL8PH45pPC", a.Protocols[2].Value);
 
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress((string)null));
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress(""));
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress("   "));
+            Assert.AreEqual(0, new MultiAddress((string)null).Protocols.Count);
+            Assert.AreEqual(0, new MultiAddress("").Protocols.Count);
+            Assert.AreEqual(0, new MultiAddress("  ").Protocols.Count);
         }
 
         [TestMethod]
@@ -189,18 +189,10 @@ public void Reading_Invalid_Code()
             ExceptionAssert.Throws<InvalidDataException>(() => new MultiAddress(new byte[] { 0x7F }));
         }
 
-        [TestMethod]
-        public void Reading_Empty()
-        {
-            ExceptionAssert.Throws<Exception>(() => new MultiAddress(new byte[0]));
-        }
 
         [TestMethod]
         public void Reading_Invalid_Text()
         {
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress((string)null));
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress(""));
-            ExceptionAssert.Throws<ArgumentNullException>(() => new MultiAddress("  "));
             ExceptionAssert.Throws<FormatException>(() => new MultiAddress("tcp/80"));
         }
 
@@ -312,8 +304,6 @@ public void Ipv6ScopeId_Ignored()
         public void TryCreate_FromString()
         {
             Assert.IsNotNull(MultiAddress.TryCreate("/ip4/1.2.3.4/tcp/80"));
-            Assert.IsNull(MultiAddress.TryCreate((string)null));
-            Assert.IsNull(MultiAddress.TryCreate(" "));
             Assert.IsNull(MultiAddress.TryCreate("/tcp/alpha")); // bad port
             Assert.IsNull(MultiAddress.TryCreate("/foobar")); // bad protocol
         }
@@ -325,7 +315,7 @@ public void TryCreate_FromBytes()
             var good1 = MultiAddress.TryCreate(good.ToArray());
             Assert.AreEqual(good, good1);
 
-            Assert.IsNull(MultiAddress.TryCreate(new byte[0]));
+            Assert.IsNull(MultiAddress.TryCreate(new byte[] { 0x7f }));
         }
 
         [TestMethod]