Better NuGet support with the legacy tag

Author: Jake Ginnivan

GitVersionCore/SemanticVersionPreReleaseTag.cs

@@ -133,14 +133,31 @@ public string ToString(string format, IFormatProvider formatProvider = null)
                 case "t":
                     return Number.HasValue ? string.Format("{0}.{1}", Name, Number) : Name;
                 case "l":
-                    return Number.HasValue ? string.Format("{0}{1}", Name, Number) : Name;
+                    return Number.HasValue ? FormatLegacy(GetLegacyName(), Number.ToString()) : FormatLegacy(GetLegacyName());
                 case "lp":
-                    return Number.HasValue ? string.Format("{0}{1}", Name, Number.Value.ToString("D4")) : Name;
+                    return Number.HasValue ? FormatLegacy(GetLegacyName(), Number.Value.ToString("D4")) : FormatLegacy(GetLegacyName());
                 default:
                     throw new ArgumentException("Unknown format", "format");
             }
         }
 
+        string FormatLegacy(string tag, string number = null)
+        {
+            var tagLength = tag.Length;
+            var numberLength = number == null ? 0 : number.Length;
+
+            if (tagLength + numberLength > 20)
+                return string.Format("{0}{1}", tag.Substring(0, 20 - numberLength), number);
+
+            return string.Format("{0}{1}", tag, number);
+        }
+
+        string GetLegacyName()
+        {
+            var firstPart = Name.Split('_')[0];
+            return firstPart.Replace("-", string.Empty).Replace(".", string.Empty);
+        }
+
         public bool HasTag()
         {
             return !string.IsNullOrEmpty(Name);

Tests/SemanticVersionTests.cs

@@ -1,5 +1,6 @@
 using GitVersion;
 using NUnit.Framework;
+using Shouldly;
 
 [TestFixture]
 public class SemanticVersionTests
@@ -51,5 +52,14 @@ public void ValidateInvalidVersionParsing(string versionString)
         Assert.IsFalse(SemanticVersion.TryParse(versionString, out version), "TryParse Result");
     }
 
+    [Test]
+    public void LegacySemVerTest()
+    {
+        new SemanticVersionPreReleaseTag("TKT-2134_JiraDescription", null).ToString("l").ShouldBe("TKT2134");
+        new SemanticVersionPreReleaseTag("AReallyReallyReallyLongBranchName", null).ToString("l").ShouldBe("AReallyReallyReallyL");
+        new SemanticVersionPreReleaseTag("TKT-2134_JiraDescription", 1).ToString("lp").ShouldBe("TKT21340001");
+        new SemanticVersionPreReleaseTag("AReallyReallyReallyLongBranchName", 1).ToString("lp").ShouldBe("AReallyReallyRea0001");
+    }
+
 
 }