Ensure calculated pre-release tag matches branch configuration

src/GitVersionCore.Tests/IntegrationTests/FeatureBranchScenarios.cs

@@ -175,6 +175,31 @@ public void ShouldBePossibleToMergeDevelopForALongRunningBranchWhereDevelopAndMa
         }
     }
 
+    [Test]
+    public void CanUseBranchNameOffAReleaseBranch()
+    {
+        var config = new Config
+        {
+            Branches =
+            {
+                { "release", new BranchConfig { Tag = "build" } },
+                { "feature", new BranchConfig { Tag = "useBranchName" } }
+            }
+        };
+
+        using (var fixture = new EmptyRepositoryFixture())
+        {
+            fixture.MakeACommit();
+            fixture.BranchTo("release/0.3.0");
+            fixture.MakeATaggedCommit("v0.3.0-build.1");
+            fixture.MakeACommit();
+            fixture.BranchTo("feature/PROJ-1");
+            fixture.MakeACommit();
+
+            fixture.AssertFullSemver(config, "0.3.0-PROJ-1.1+2");
+        }
+    }
+
     [TestCase("alpha", "JIRA-123", "alpha")]
     [TestCase("useBranchName", "JIRA-123", "JIRA-123")]
     [TestCase("alpha.{BranchName}", "JIRA-123", "alpha.JIRA-123")]
@@ -191,12 +216,12 @@ public void ShouldUseConfiguredTag(string tag, string featureName, string preRel
         using (var fixture = new EmptyRepositoryFixture())
         {
             fixture.Repository.MakeATaggedCommit("1.0.0");
-            var featureBranchName = string.Format("feature/{0}", featureName);
+            var featureBranchName = $"feature/{featureName}";
             fixture.Repository.CreateBranch(featureBranchName);
             Commands.Checkout(fixture.Repository, featureBranchName);
             fixture.Repository.MakeCommits(5);
 
-            var expectedFullSemVer = string.Format("1.0.1-{0}.1+5", preReleaseTagName);
+            var expectedFullSemVer = $"1.0.1-{preReleaseTagName}.1+5";
             fixture.AssertFullSemver(config, expectedFullSemVer);
         }
     }

src/GitVersionCore.Tests/IntegrationTests/OtherBranchScenarios.cs

@@ -54,7 +54,7 @@ public void ShouldNotGetVersionFromFeatureBranchIfNotMerged()
             fixture.Repository.MakeACommit();
 
             var version = fixture.GetVersion();
-            version.SemVer.ShouldBe("1.0.0-unstable.1");
+            version.SemVer.ShouldBe("1.0.0-alpha.1");
         }
     }
 }

src/GitVersionCore.Tests/IntegrationTests/ReleaseBranchScenarios.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using GitTools;
-using GitTools.Testing;
+using GitTools.Testing;
 using GitVersion;
 using GitVersionCore.Tests;
 using LibGit2Sharp;

src/GitVersionCore/VersionCalculation/NextVersionCalculator.cs

@@ -52,7 +52,10 @@ public SemanticVersion FindVersion(GitVersionContext context)
                 semver.BuildMetaData = metaDataCalculator.Create(baseVersion.BaseVersionSource, context);
             }
 
-            if (!semver.PreReleaseTag.HasTag() && !string.IsNullOrEmpty(context.Configuration.Tag))
+            var hasPreReleaseTag = semver.PreReleaseTag.HasTag();
+            var branchConfigHasPreReleaseTagConfigured = !string.IsNullOrEmpty(context.Configuration.Tag);
+            var preReleaseTagDoesNotMatchConfiguration = hasPreReleaseTag && branchConfigHasPreReleaseTagConfigured && semver.PreReleaseTag.Name != context.Configuration.Tag;
+            if (!semver.PreReleaseTag.HasTag() && branchConfigHasPreReleaseTagConfigured || preReleaseTagDoesNotMatchConfiguration)
             {
                 UpdatePreReleaseTag(context, semver, baseVersion.BranchNameOverride);
             }

src/GitVersionExe/SpecifiedArgumentRunner.cs

@@ -49,7 +49,7 @@ public static void Run(Arguments arguments, IFileSystem fileSystem)
                         string part;
                         if (!variables.TryGetValue(arguments.ShowVariable, out part))
                         {
-                            throw new WarningException(string.Format("'{0}' variable does not exist", arguments.ShowVariable));
+                            throw new WarningException($"'{arguments.ShowVariable}' variable does not exist");
                         }
                         Console.WriteLine(part);
                         break;