fix semantic versions always ignoring `-0` tag (#421)

6 files changed, 47 insertions, 4 deletions

diff --git a/docs/release-notes.md b/docs/release-notes.md
index 87ef671e..4b6a7ba5 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -2,6 +2,7 @@
 ## 2.4
 * For players:
   * SMAPI now fixes curly quotes in `config.json` if possible.
+  * Fixed semantic versions always ignoring `-0` tag.
   * Fixed rare issues caused by assembly references being incorrectly loaded twice.
 
 * For the [log parser][]:
diff --git a/src/SMAPI.Common/SemanticVersionImpl.cs b/src/SMAPI.Common/SemanticVersionImpl.cs
index 53cf5a21..1c713b47 100644
--- a/src/SMAPI.Common/SemanticVersionImpl.cs
+++ b/src/SMAPI.Common/SemanticVersionImpl.cs
@@ -190,9 +190,7 @@ namespace StardewModdingAPI.Common
         private string GetNormalisedTag(string tag)
         {
             tag = tag?.Trim();
-            if (string.IsNullOrWhiteSpace(tag) || tag == "0") // '0' from incorrect examples in old SMAPI documentation
-                return null;
-            return tag;
+            return !string.IsNullOrWhiteSpace(tag) ? tag : null;
         }
     }
 }
diff --git a/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs b/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
index d3e0988e..f1a72012 100644
--- a/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
+++ b/src/SMAPI.Tests/Utilities/SemanticVersionTests.cs
@@ -33,6 +33,7 @@ namespace StardewModdingAPI.Tests.Utilities
         [TestCase(3000, 4000, 5000, null, ExpectedResult = "3000.4000.5000")]
         [TestCase(1, 2, 3, "", ExpectedResult = "1.2.3")]
         [TestCase(1, 2, 3, "    ", ExpectedResult = "1.2.3")]
+        [TestCase(1, 2, 3, "0", ExpectedResult = "1.2.3-0")]
         [TestCase(1, 2, 3, "some-tag.4", ExpectedResult = "1.2.3-some-tag.4")]
         [TestCase(1, 2, 3, "some-tag.4   ", ExpectedResult = "1.2.3-some-tag.4")]
         public string Constructor_FromParts(int major, int minor, int patch, string tag)
@@ -270,6 +271,22 @@ namespace StardewModdingAPI.Tests.Utilities
             Assert.IsTrue(version.IsOlderThan(new SemanticVersion("1.2.30")), "The game version should be considered older than the later semantic versions.");
         }
 
+        /****
+        ** LegacyManifestVersion
+        ****/
+        [Test(Description = "Assert that the LegacyManifestVersion subclass correctly parses legacy manifest versions.")]
+        [TestCase(1, 0, 0, null, ExpectedResult = "1.0")]
+        [TestCase(3000, 4000, 5000, null, ExpectedResult = "3000.4000.5000")]
+        [TestCase(1, 2, 3, "", ExpectedResult = "1.2.3")]
+        [TestCase(1, 2, 3, "    ", ExpectedResult = "1.2.3")]
+        [TestCase(1, 2, 3, "0", ExpectedResult = "1.2.3")]  // special case: drop '0' tag for legacy manifest versions
+        [TestCase(1, 2, 3, "some-tag.4", ExpectedResult = "1.2.3-some-tag.4")]
+        [TestCase(1, 2, 3, "some-tag.4   ", ExpectedResult = "1.2.3-some-tag.4")]
+        public string LegacyManifestVersion(int major, int minor, int patch, string tag)
+        {
+            return new LegacyManifestVersion(major, minor, patch, tag).ToString();
+        }
+
 
         /*********
         ** Private methods
diff --git a/src/SMAPI/Framework/LegacyManifestVersion.cs b/src/SMAPI/Framework/LegacyManifestVersion.cs
new file mode 100644
index 00000000..454b9137
--- /dev/null
+++ b/src/SMAPI/Framework/LegacyManifestVersion.cs
@@ -0,0 +1,26 @@
+using Newtonsoft.Json;
+
+namespace StardewModdingAPI.Framework
+{
+    /// <summary>An implementation of <see cref="ISemanticVersion"/> that hamdles the legacy <see cref="IManifest"/> version format.</summary>
+    internal class LegacyManifestVersion : SemanticVersion
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="majorVersion">The major version incremented for major API changes.</param>
+        /// <param name="minorVersion">The minor version incremented for backwards-compatible changes.</param>
+        /// <param name="patchVersion">The patch version for backwards-compatible bug fixes.</param>
+        /// <param name="build">An optional build tag.</param>
+        [JsonConstructor]
+        public LegacyManifestVersion(int majorVersion, int minorVersion, int patchVersion, string build = null)
+            : base(
+                majorVersion,
+                minorVersion,
+                patchVersion,
+                build != "0" ? build : null // '0' from incorrect examples in old SMAPI documentation
+            )
+        { }
+    }
+}
diff --git a/src/SMAPI/Framework/Serialisation/SFieldConverter.cs b/src/SMAPI/Framework/Serialisation/SFieldConverter.cs
index 917c950d..6e068599 100644
--- a/src/SMAPI/Framework/Serialisation/SFieldConverter.cs
+++ b/src/SMAPI/Framework/Serialisation/SFieldConverter.cs
@@ -51,7 +51,7 @@ namespace StardewModdingAPI.Framework.Serialisation
                             int minor = obj.Value<int>(nameof(ISemanticVersion.MinorVersion));
                             int patch = obj.Value<int>(nameof(ISemanticVersion.PatchVersion));
                             string build = obj.Value<string>(nameof(ISemanticVersion.Build));
-                            return new SemanticVersion(major, minor, patch, build);
+                            return new LegacyManifestVersion(major, minor, patch, build);
                         }
 
                     case JTokenType.String:
diff --git a/src/SMAPI/StardewModdingAPI.csproj b/src/SMAPI/StardewModdingAPI.csproj
index f76ac439..c9c302f5 100644
--- a/src/SMAPI/StardewModdingAPI.csproj
+++ b/src/SMAPI/StardewModdingAPI.csproj
@@ -86,6 +86,7 @@
       <Link>Properties\GlobalAssemblyInfo.cs</Link>
     </Compile>
     <Compile Include="Framework\Content\ContentCache.cs" />
+    <Compile Include="Framework\LegacyManifestVersion.cs" />
     <Compile Include="Framework\Models\ModCompatibility.cs" />
     <Compile Include="Framework\ModLoading\Finders\EventFinder.cs" />
     <Compile Include="Framework\ModLoading\Finders\FieldFinder.cs" />