From ee7a8f60abb29fac07c2570cb71ca5b6aab41897 Mon Sep 17 00:00:00 2001
From: mpilquist <mpilquist@gmail.com>
Date: Mon, 27 Sep 2021 08:39:24 -0400
Subject: [PATCH] Fix #317

---
 shared/src/main/scala/com/comcast/ip4s/Host.scala         | 8 +++++---
 .../src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala | 5 +++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/shared/src/main/scala/com/comcast/ip4s/Host.scala b/shared/src/main/scala/com/comcast/ip4s/Host.scala
index 8570ae6f..9761d656 100644
--- a/shared/src/main/scala/com/comcast/ip4s/Host.scala
+++ b/shared/src/main/scala/com/comcast/ip4s/Host.scala
@@ -576,10 +576,12 @@ object Ipv6Address extends Ipv6AddressCompanionPlatform {
     var beforeCondenser = true
     var suffix: List[Int] = Nil
     val trimmed = value.trim()
+    var result: Option[Ipv6Address] = null
     val fields =
-      if (trimmed.nonEmpty) trimmed.split(":") else Array.empty[String]
+      if (trimmed.contains(':')) trimmed.split(':')
+      else Array.empty[String]
+    // if (trimmed.nonEmpty) trimmed.split(':') else Array.empty[String]
     var idx = 0
-    var result: Option[Ipv6Address] = null
     while (idx < fields.size && (result eq null)) {
       val field = fields(idx)
       if (field.isEmpty) {
@@ -607,7 +609,7 @@ object Ipv6Address extends Ipv6AddressCompanionPlatform {
     }
     if (result ne null) {
       result
-    } else if (fields.isEmpty && (trimmed.isEmpty || trimmed == ":")) {
+    } else if (fields.isEmpty && (trimmed.isEmpty || trimmed != "::")) {
       None
     } else {
       val bytes = new Array[Byte](16)
diff --git a/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala b/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala
index 41026b37..4cab33c3 100644
--- a/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala
+++ b/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala
@@ -34,6 +34,7 @@ class Ipv6AddressTest extends BaseTestSuite {
     assertEquals(Ipv6Address.fromString(":"), None)
     assertEquals(Ipv6Address.fromString(" : "), None)
   }
+
   test("parsing from string - does parse ::") {
     assertEquals(Ipv6Address.fromString("::").isDefined, true)
     assertEquals(Ipv6Address.fromString(" :: ").isDefined, true)
@@ -46,6 +47,10 @@ class Ipv6AddressTest extends BaseTestSuite {
     }
   }
 
+  test("parsing from string - does not misinterpret hosts") {
+    assertEquals(Ipv6Address.fromString("db"), None)
+  }
+
   test("support converting to uncondensed string form") {
     forAll(Gen.listOfN(16, Arbitrary.arbitrary[Byte])) { bytesList =>
       if (bytesList.size == 16) {