improve semantic version validation

docs/release-notes.md

@@ -46,6 +46,7 @@
   * Fixed some common non-mod build output being included in release zip.
   * Fixed mods able to intercept other mods' assets via the internal asset keys.
   * Fixed mods able to indirectly change other mods' data through shared content caches.
+  * Fixed `SemanticVersion` allowing invalid versions in some cases.
   * **Breaking changes** (see [migration guide](https://stardewvalleywiki.com/Modding:Migrate_to_Stardew_Valley_1.3)):
      * Dropped some deprecated APIs.
      * `LocationEvents` have been rewritten.

src/SMAPI.Tests/Utilities/SemanticVersionTests.cs

@@ -49,6 +49,19 @@ namespace StardewModdingAPI.Tests.Utilities
             return version.ToString();
         }
 
+        [Test(Description = "Assert that the constructor throws the expected exception for invalid versions when constructed from the individual numbers.")]
+        [TestCase(0, 0, 0, null)]
+        [TestCase(-1, 0, 0, null)]
+        [TestCase(0, -1, 0, null)]
+        [TestCase(0, 0, -1, null)]
+        [TestCase(1, 0, 0, "-tag")]
+        [TestCase(1, 0, 0, "tag spaces")]
+        [TestCase(1, 0, 0, "tag~")]
+        public void Constructor_FromParts_WithInvalidValues(int major, int minor, int patch, string tag)
+        {
+            this.AssertAndLogException<FormatException>(() => new SemanticVersion(major, minor, patch, tag));
+        }
+
         [Test(Description = "Assert that the constructor sets the expected values for all valid versions when constructed from an assembly version.")]
         [TestCase(1, 0, 0, ExpectedResult = "1.0")]
         [TestCase(1, 2, 3, ExpectedResult = "1.2.3")]
@@ -79,6 +92,7 @@ namespace StardewModdingAPI.Tests.Utilities
         [TestCase("1.2.3.apple")]
         [TestCase("1..2..3")]
         [TestCase("1.2.3-")]
+        [TestCase("1.2.3--some-tag")]
         [TestCase("1.2.3-some-tag...")]
         [TestCase("1.2.3-some-tag...4")]
         [TestCase("apple")]

src/StardewModdingAPI.Toolkit/SemanticVersion.cs

@@ -10,8 +10,11 @@ namespace StardewModdingAPI.Toolkit
         /*********
         ** Properties
         *********/
+        /// <summary>A regex pattern matching a valid prerelease tag.</summary>
+        internal const string TagPattern = @"(?>[a-z0-9]+[\-\.]?)+";
+
         /// <summary>A regex pattern matching a version within a larger string.</summary>
-        internal const string UnboundedVersionPattern = @"(?>(?<major>0|[1-9]\d*))\.(?>(?<minor>0|[1-9]\d*))(?>(?:\.(?<patch>0|[1-9]\d*))?)(?:-(?<prerelease>(?>[a-z0-9]+[\-\.]?)+))?";
+        internal const string UnboundedVersionPattern = @"(?>(?<major>0|[1-9]\d*))\.(?>(?<minor>0|[1-9]\d*))(?>(?:\.(?<patch>0|[1-9]\d*))?)(?:-(?<prerelease>" + SemanticVersion.TagPattern + "))?";
 
         /// <summary>A regular expression matching a semantic version string.</summary>
         /// <remarks>
@@ -54,6 +57,8 @@ namespace StardewModdingAPI.Toolkit
             this.Minor = minor;
             this.Patch = patch;
             this.Tag = this.GetNormalisedTag(tag);
+
+            this.AssertValid();
         }
 
         /// <summary>Construct an instance.</summary>
@@ -67,6 +72,8 @@ namespace StardewModdingAPI.Toolkit
             this.Major = version.Major;
             this.Minor = version.Minor;
             this.Patch = version.Build;
+
+            this.AssertValid();
         }
 
         /// <summary>Construct an instance.</summary>
@@ -87,6 +94,8 @@ namespace StardewModdingAPI.Toolkit
             this.Minor = match.Groups["minor"].Success ? int.Parse(match.Groups["minor"].Value) : 0;
             this.Patch = match.Groups["patch"].Success ? int.Parse(match.Groups["patch"].Value) : 0;
             this.Tag = match.Groups["prerelease"].Success ? this.GetNormalisedTag(match.Groups["prerelease"].Value) : null;
+
+            this.AssertValid();
         }
 
         /// <summary>Get an integer indicating whether this version precedes (less than 0), supercedes (more than 0), or is equivalent to (0) the specified version.</summary>
@@ -235,5 +244,21 @@ namespace StardewModdingAPI.Toolkit
             // fallback (this should never happen)
             return string.Compare(this.ToString(), new SemanticVersion(otherMajor, otherMinor, otherPatch, otherTag).ToString(), StringComparison.InvariantCultureIgnoreCase);
         }
+
+        /// <summary>Assert that the current version is valid.</summary>
+        private void AssertValid()
+        {
+            if (this.Major < 0 || this.Minor < 0 || this.Patch < 0)
+                throw new FormatException($"{this} isn't a valid semantic version. The major, minor, and patch numbers can't be negative.");
+            if (this.Major == 0 && this.Minor == 0 && this.Patch == 0)
+                throw new FormatException($"{this} isn't a valid semantic version. At least one of the major, minor, and patch numbers must be more than zero.");
+            if (this.Tag != null)
+            {
+                if (this.Tag.Trim() == "")
+                    throw new FormatException($"{this} isn't a valid semantic version. The tag cannot be a blank string (but may be omitted).");
+                if (!Regex.IsMatch(this.Tag, $"^{SemanticVersion.TagPattern}$"))
+                    throw new FormatException($"{this} isn't a valid semantic version. The tag is invalid.");
+            }
+        }
     }
 }