Introduced source-branches config option

This allows GitVersion to know what branches it should take into account for calculating merge base. This locks it down a little more, but is an easier to explain behavior than commit counting randomly resetting because GitVersion cannot effectively figure out which branch the current branch was branched off.

Author: JakeGinnivan

docs/configuration.md

@@ -243,6 +243,41 @@ values, but here they are if you need to:
 ### regex
 This is the regex which is used to match the current branch to the correct branch configuration.
 
+### source-branches
+Because git is a directed graph GitVersion sometimes cannot tell which branch the current branch was branched from.
+
+Take this graph
+
+```
+  *   feature/foo
+* |   release/1.0.0
+|/
+*
+*
+* (master)
+```
+
+By looking at this graph, you cannot tell which of these scenarios happened
+
+1. feature/foo branches off release/1.0.0
+   - Branch release/1.0.0 from master
+   - Branch feature/foo from release/1.0.0
+   - Add a commit to both release/1.0.0 and feature/foo
+   - release/1.0.0 is the base for feature/foo
+
+2. release/1.0.0 branches off feature/foo
+   - Branch feature/foo from master
+   - Branch release/1.0.0 from feature/foo 
+   - Add a commit to both release/1.0.0 and feature/foo
+   - feature/foo is the base for release/1.0.0
+
+To resolve this issue we give GitVersion a hint to how we normally do our branching, feature branches have a value of:
+
+`sourceBranches: ['master', 'develop', 'feature', 'hotfix', 'support']`
+
+This means that we will never bother to evaluate pull requests as merge base options, being explicit like this helps GitVersion be much faster too.
+
+
 ### branches
 The header for all the individual branch configuration.
 

src/GitVersionCore.Tests/ConfigProviderTests.CanWriteOutEffectiveConfiguration.approved.txt

@@ -12,13 +12,27 @@ build-metadata-padding: 4
 commits-since-version-source-padding: 4
 commit-message-incrementing: Enabled
 branches:
+  develop:
+    mode: ContinuousDeployment
+    tag: alpha
+    increment: Minor
+    prevent-increment-of-merged-branch-version: false
+    track-merge-target: true
+    regex: dev(elop)?(ment)?$
+    source-branches: []
+    tracks-release-branches: true
+    is-release-branch: false
+    is-mainline: false
   master:
     mode: ContinuousDelivery
     tag: ''
     increment: Patch
     prevent-increment-of-merged-branch-version: true
     track-merge-target: false
     regex: master
+    source-branches:
+    - develop
+    - release
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: true
@@ -29,6 +43,9 @@ branches:
     prevent-increment-of-merged-branch-version: true
     track-merge-target: false
     regex: releases?[/-]
+    source-branches:
+    - develop
+    - master
     tracks-release-branches: false
     is-release-branch: true
     is-mainline: false
@@ -39,6 +56,13 @@ branches:
     prevent-increment-of-merged-branch-version: false
     track-merge-target: false
     regex: features?[/-]
+    source-branches:
+    - develop
+    - master
+    - release
+    - feature
+    - support
+    - hotfix
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: false
@@ -50,6 +74,13 @@ branches:
     tag-number-pattern: '[/-](?<number>\d+)'
     track-merge-target: false
     regex: (pull|pull\-requests|pr)[/-]
+    source-branches:
+    - develop
+    - master
+    - release
+    - feature
+    - support
+    - hotfix
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: false
@@ -60,6 +91,9 @@ branches:
     prevent-increment-of-merged-branch-version: false
     track-merge-target: false
     regex: hotfix(es)?[/-]
+    source-branches:
+    - develop
+    - master
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: false
@@ -70,18 +104,10 @@ branches:
     prevent-increment-of-merged-branch-version: true
     track-merge-target: false
     regex: support[/-]
+    source-branches:
+    - master
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: true
-  develop:
-    mode: ContinuousDeployment
-    tag: alpha
-    increment: Minor
-    prevent-increment-of-merged-branch-version: false
-    track-merge-target: true
-    regex: dev(elop)?(ment)?$
-    tracks-release-branches: true
-    is-release-branch: false
-    is-mainline: false
 ignore:
   sha: []

src/GitVersionCore.Tests/ConfigProviderTests.cs

@@ -111,7 +111,8 @@ public void CanProvideConfigForNewBranch()
 branches:
     bug:
         regex: 'bug[/-]'
-        tag: bugfix";
+        tag: bugfix
+        source-branches: []";
         SetupConfigFileContent(text);
         var config = ConfigurationProvider.Provide(repoPath, fileSystem);
 

src/GitVersionCore.Tests/GitVersionContextTests.cs

@@ -98,8 +98,8 @@ public void UsesFirstBranchConfigWhenMultipleMatch()
                 VersioningMode = VersioningMode.ContinuousDelivery,
                 Branches =
                 {
-                    { "release/latest", new BranchConfig { Increment = IncrementStrategy.None, Regex = "release/latest" } },
-                    { "release", new BranchConfig { Increment = IncrementStrategy.Patch, Regex = "releases?[/-]" } }
+                    { "release/latest", new BranchConfig { Increment = IncrementStrategy.None, Regex = "release/latest", SourceBranches = new string[0] } },
+                    { "release", new BranchConfig { Increment = IncrementStrategy.Patch, Regex = "releases?[/-]", SourceBranches = new string[0] } }
                 }
             }.ApplyDefaults();
 

src/GitVersionCore.Tests/IntegrationTests/DevelopScenarios.cs

@@ -64,7 +64,8 @@ public void CanChangeDevelopTagViaConfig()
                 {
                     "develop", new BranchConfig
                     {
-                        Tag = "alpha"
+                        Tag = "alpha",
+                        SourceBranches = new string[0]
                     }
                 }
             }

src/GitVersionCore.Tests/IntegrationTests/FeatureBranchScenarios.cs

@@ -42,7 +42,9 @@ public void BranchCreatedAfterFastForwardMergeShouldInheritCorrectly()
         {
             Branches =
             {
-                { "unstable", new BranchConfig { Increment = IncrementStrategy.Minor, Regex = "unstable"} }
+                { "unstable", new BranchConfig {
+                    Increment = IncrementStrategy.Minor, Regex = "unstable", SourceBranches = new string[0]
+                } }
             }
         };
 

src/GitVersionCore.Tests/IntegrationTests/OtherScenarios.cs

@@ -56,7 +56,8 @@ public void AllowHavingMainInsteadOfMaster()
                 Tag = "useBranchName",
                 Increment = IncrementStrategy.Patch,
                 PreventIncrementOfMergedBranchVersion = true,
-                TrackMergeTarget = false
+                TrackMergeTarget = false,
+                SourceBranches = new string[0]
             });
 
             using (var fixture = new EmptyRepositoryFixture())

src/GitVersionCore.Tests/IntegrationTests/VersionBumpingScenarios.cs

@@ -13,7 +13,13 @@ public void AppliedPrereleaseTagCausesBump()
         {
             Branches =
             {
-                { "master", new BranchConfig { Tag = "pre" } }
+                {
+                    "master", new BranchConfig
+                    {
+                        Tag = "pre",
+                        SourceBranches = new string[0]
+                    }
+                }
             }
         };
         using (var fixture = new EmptyRepositoryFixture())

src/GitVersionCore.Tests/VersionCalculation/NextVersionCalculatorTests.cs

@@ -67,7 +67,8 @@ public void PreReleaseTagCanUseBranchName()
                         "custom", new BranchConfig
                         {
                             Regex = "custom/",
-                            Tag = "useBranchName"
+                            Tag = "useBranchName",
+                            SourceBranches = new string[0]
                         }
                     }
                 }
@@ -97,7 +98,8 @@ public void PreReleaseTagCanUseBranchNameVariable()
                         "custom", new BranchConfig
                         {
                             Regex = "custom/",
-                            Tag = "alpha.{BranchName}"
+                            Tag = "alpha.{BranchName}",
+                            SourceBranches = new string[0]
                         }
                     }
                 }

src/GitVersionCore/BranchConfigurationCalculator.cs

@@ -22,7 +22,7 @@ public static BranchConfig GetBranchConfiguration(GitVersionContext context, Bra
                     targetBranch.FriendlyName));
 
                 matchingBranches = new BranchConfig { Name = string.Empty };
-                ConfigurationProvider.ApplyBranchDefaults(context.FullConfiguration, matchingBranches, "");
+                ConfigurationProvider.ApplyBranchDefaults(context.FullConfiguration, matchingBranches, "", new string[0]);
             }
 
             return matchingBranches.Increment == IncrementStrategy.Inherit ?

src/GitVersionCore/Configuration/BranchConfig.cs

@@ -54,6 +54,9 @@ public BranchConfig(BranchConfig branchConfiguration)
         [YamlMember(Alias = "regex")]
         public string Regex { get; set; }
 
+        [YamlMember(Alias = "source-branches")]
+        public string[] SourceBranches { get; set; }
+
         [YamlMember(Alias = "tracks-release-branches")]
         public bool? TracksReleaseBranches { get; set; }
 

src/GitVersionCore/Configuration/ConfigurationProvider.cs

@@ -101,50 +101,57 @@ public static void ApplyDefaultsTo(Config config)
 
             var configBranches = config.Branches.ToList();
 
+            ApplyBranchDefaults(config,
+                GetOrCreateBranchDefaults(config, DevelopBranchKey),
+                DevelopBranchRegex,
+                new string[0],
+                defaultTag: "alpha",
+                defaultIncrementStrategy: IncrementStrategy.Minor,
+                defaultVersioningMode: VersioningMode.ContinuousDeployment,
+                defaultTrackMergeTarget: true,
+                tracksReleaseBranches: true);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, MasterBranchKey),
                 MasterBranchRegex,
+                new string[] { "develop", "release" },
                 defaultTag: string.Empty,
                 defaultPreventIncrement: true,
                 defaultIncrementStrategy: IncrementStrategy.Patch,
                 isMainline: true);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, ReleaseBranchKey),
                 ReleaseBranchRegex,
+                new string[] { "develop", "master" },
                 defaultTag: "beta",
                 defaultPreventIncrement: true,
                 defaultIncrementStrategy: IncrementStrategy.Patch,
                 isReleaseBranch: true);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, FeatureBranchKey),
                 FeatureBranchRegex,
+                new string[] { "develop", "master", "release", "feature", "support", "hotfix" },
                 defaultIncrementStrategy: IncrementStrategy.Inherit);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, PullRequestBranchKey),
                 PullRequestRegex,
+                new string[] { "develop", "master", "release", "feature", "support", "hotfix" },
                 defaultTag: "PullRequest",
                 defaultTagNumberPattern: @"[/-](?<number>\d+)",
                 defaultIncrementStrategy: IncrementStrategy.Inherit);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, HotfixBranchKey),
                 HotfixBranchRegex,
+                new string[] { "develop", "master" },
                 defaultTag: "beta",
                 defaultIncrementStrategy: IncrementStrategy.Patch);
             ApplyBranchDefaults(config,
                 GetOrCreateBranchDefaults(config, SupportBranchKey),
                 SupportBranchRegex,
+                new string[] { "master" },
                 defaultTag: string.Empty,
                 defaultPreventIncrement: true,
                 defaultIncrementStrategy: IncrementStrategy.Patch,
                 isMainline: true);
-            ApplyBranchDefaults(config,
-                GetOrCreateBranchDefaults(config, DevelopBranchKey),
-                DevelopBranchRegex,
-                defaultTag: "alpha",
-                defaultIncrementStrategy: IncrementStrategy.Minor,
-                defaultVersioningMode: VersioningMode.ContinuousDeployment,
-                defaultTrackMergeTarget: true,
-                tracksReleaseBranches: true);
 
             // Any user defined branches should have other values defaulted after known branches filled in.
             // This allows users to override any of the value.
@@ -153,10 +160,16 @@ public static void ApplyDefaultsTo(Config config)
                 var regex = branchConfig.Value.Regex;
                 if (regex == null)
                 {
-                    throw new GitVersionConfigurationException(string.Format("Branch configuration '{0}' is missing required configuration 'regex'", branchConfig.Key));
+                    throw new GitVersionConfigurationException($"Branch configuration '{branchConfig.Key}' is missing required configuration 'regex'");
+                }
+
+                var sourceBranches = branchConfig.Value.SourceBranches;
+                if (sourceBranches == null)
+                {
+                    throw new GitVersionConfigurationException($"Branch configuration '{branchConfig.Key}' is missing required configuration 'source-branches'");
                 }
 
-                ApplyBranchDefaults(config, branchConfig.Value, regex);
+                ApplyBranchDefaults(config, branchConfig.Value, regex, sourceBranches);
             }
         }
 
@@ -180,6 +193,7 @@ static BranchConfig GetOrCreateBranchDefaults(Config config, string branchKey)
         public static void ApplyBranchDefaults(Config config,
             BranchConfig branchConfig,
             string branchRegex,
+            string[] sourceBranches,
             string defaultTag = "useBranchName",
             IncrementStrategy? defaultIncrementStrategy = null, // Looked up from main config
             bool defaultPreventIncrement = false,
@@ -191,6 +205,7 @@ public static void ApplyBranchDefaults(Config config,
             bool isMainline = false)
         {
             branchConfig.Regex = string.IsNullOrEmpty(branchConfig.Regex) ? branchRegex : branchConfig.Regex;
+            branchConfig.SourceBranches = sourceBranches;
             branchConfig.Tag = branchConfig.Tag ?? defaultTag;
             branchConfig.TagNumberPattern = branchConfig.TagNumberPattern ?? defaultTagNumberPattern;
             branchConfig.Increment = branchConfig.Increment ?? defaultIncrementStrategy ?? config.Increment ?? DefaultIncrementStrategy;