[Bugfix] Wrong version number observed in a feature branch after a tagged develop is merged into it

src/GitVersionCore.Tests/IntegrationTests/DevelopScenarios.cs

@@ -201,7 +201,7 @@ public void WhenMultipleDevelopBranchesExistAndCurrentBranchHasIncrementInheritP
             fixture.Repository.MakeACommit();
             fixture.Repository.MergeNoFF("develop");
 
-            fixture.AssertFullSemver("1.0.1-x.1+3");
+            fixture.AssertFullSemver("1.1.0-x.1+3");
         }
     }
 }

src/GitVersionCore.Tests/IntegrationTests/FeatureBranchScenarios.cs

@@ -552,4 +552,49 @@ public void PickUpVersionFromMasterMarkedWithIsTracksReleaseBranches()
             fixture.AssertFullSemver(config, "0.10.1-MyFeatureD.1+1");
         }
     }
+
+    [Test]
+    public void ShouldHaveAGreaterSemVerAfterDevelopIsMergedIntoFeature()
+    {
+        var config = new Config()
+        {
+            VersioningMode = VersioningMode.ContinuousDeployment,
+            AssemblyVersioningScheme = AssemblyVersioningScheme.Major,
+            AssemblyFileVersioningFormat = "{MajorMinorPatch}.{env:WeightedPreReleaseNumber ?? 0}",
+            LegacySemVerPadding = 4,
+            BuildMetaDataPadding = 4,
+            CommitsSinceVersionSourcePadding = 4,
+            CommitMessageIncrementing = CommitMessageIncrementMode.Disabled,
+            Branches = new Dictionary<string, BranchConfig>
+            {
+                {
+                    "develop", new BranchConfig()
+                    {
+                        PreventIncrementOfMergedBranchVersion = true
+                    }
+                },
+                {
+                    "feature", new BranchConfig()
+                    {
+                        Tag = "feat-{BranchName}"
+                    }
+                }
+            }
+        };
+        using (var fixture = new EmptyRepositoryFixture())
+        {
+            fixture.MakeACommit();
+            fixture.BranchTo("develop");
+            fixture.MakeACommit();
+            fixture.ApplyTag("16.23.0");
+            fixture.MakeACommit();
+            fixture.BranchTo("feature/featX");
+            fixture.MakeACommit();
+            fixture.Checkout("develop");
+            fixture.MakeACommit();
+            fixture.Checkout("feature/featX");
+            fixture.MergeNoFF("develop");
+            fixture.AssertFullSemver(config, "16.24.0-feat-featX.4");
+        }
+    }
 }

src/GitVersionCore/BranchConfigurationCalculator.cs

@@ -142,11 +142,21 @@ static BranchConfig InheritBranchConfiguration(GitVersionContext context, Branch
                 // To prevent infinite loops, make sure that a new branch was chosen.
                 if (targetBranch.IsSameBranch(chosenBranch))
                 {
-                    Logger.WriteWarning("Fallback branch wants to inherit Increment branch configuration from itself. Using patch increment instead.");
-                    return new BranchConfig(branchConfiguration)
+                    BranchConfig developOrMasterConfig =
+                        ChooseMasterOrDevelopIncrementStrategyIfTheChosenBranchIsOneOfThem(
+                            chosenBranch, branchConfiguration, config);
+                    if (developOrMasterConfig != null)
                     {
-                        Increment = IncrementStrategy.Patch
-                    };
+                        return developOrMasterConfig;
+                    }
+                    else
+                    {
+                        Logger.WriteWarning("Fallback branch wants to inherit Increment branch configuration from itself. Using patch increment instead.");
+                        return new BranchConfig(branchConfiguration)
+                        {
+                            Increment = IncrementStrategy.Patch
+                        };
+                    }
                 }
 
                 var inheritingBranchConfig = GetBranchConfiguration(context, chosenBranch, excludedInheritBranches);
@@ -201,5 +211,39 @@ static Branch[] CalculateWhenMultipleParents(IRepository repository, Commit curr
 
             return excludedBranches;
         }
+
+        private static BranchConfig
+            ChooseMasterOrDevelopIncrementStrategyIfTheChosenBranchIsOneOfThem(Branch ChosenBranch,
+                BranchConfig BranchConfiguration, Config config)
+        {
+            BranchConfig masterOrDevelopConfig = null;
+            var developBranchRegex = config.Branches[ConfigurationProvider.DevelopBranchKey].Regex;
+            var masterBranchRegex = config.Branches[ConfigurationProvider.MasterBranchKey].Regex;
+            if (Regex.IsMatch(ChosenBranch.FriendlyName, developBranchRegex, RegexOptions.IgnoreCase))
+            {
+                // Normally we would not expect this to happen but for safety we add a check
+                if (config.Branches[ConfigurationProvider.DevelopBranchKey].Increment !=
+                    IncrementStrategy.Inherit)
+                {
+                    masterOrDevelopConfig = new BranchConfig(BranchConfiguration)
+                    {
+                        Increment = config.Branches[ConfigurationProvider.DevelopBranchKey].Increment
+                    };
+                }
+            }
+            else if (Regex.IsMatch(ChosenBranch.FriendlyName, masterBranchRegex, RegexOptions.IgnoreCase))
+            {
+                // Normally we would not expect this to happen but for safety we add a check
+                if (config.Branches[ConfigurationProvider.MasterBranchKey].Increment !=
+                    IncrementStrategy.Inherit)
+                {
+                    masterOrDevelopConfig = new BranchConfig(BranchConfiguration)
+                    {
+                        Increment = config.Branches[ConfigurationProvider.DevelopBranchKey].Increment
+                    };
+                }
+            }
+            return masterOrDevelopConfig;
+        }
     }
-}
+}