Pick better merge base

BREAKING CHANGES.md

@@ -8,6 +8,7 @@ v4.0.0
     - The default keys are: master, develop, feature, release, pull-request, hotfix, support
     - Just run GitVersion.exe in your project directory and it will tell you what to change your config keys to
     - For example, `dev(elop)?(ment)?$` is now just `develop`, we suggest not overring regex's unless you really want to use a different convention.
+ - source-branches added as a configuration option for branches, it helps GitVersion pick the correct source branch
 
 v3.0.0
  - NextVersion.txt has been deprecated, only GitVersionConfig.yaml is supported

docs/configuration.md

@@ -243,6 +243,70 @@ 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 commits only refer to parent commits (not branches) GitVersion sometimes cannot tell which branch the current branch was branched from.
+
+Take this commit graph
+
+```
+* release/1.0.0   * feature/foo
+| ________________/
+|/
+*
+*
+* (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
+
+Or put more simply, you cannot tell which branch was created first, `release/1.0.0` or `feature/foo`.
+
+To resolve this issue, we give GitVersion a hint about our branching workflows by telling it what types of branches a branch can be created from. For example, feature branches are, by default, configured to have the following source branches:
+
+`source-branches: ['master', 'develop', 'feature', 'hotfix', 'support']`
+
+This means that we will never bother to evaluate pull request branches as merge base options and being explicit in this way also improves the performance of GitVersion.
+
+### is-source-branch-for
+The reverse of `source-branches`. This property was introduced to keep it easy to extend GitVersion's config.
+
+It exists to make it easier to extend GitVersion's configuration. If only `source-branches` exists and you add a new branch type, for instance `unstable/`, you then need to re-define the `source-branches` configuration value for existing branches (like feature/) to now include the new unstable branch.
+
+A complete example:
+
+```
+branches:
+  unstable:
+    regex: ...
+    is-source-branch-for: ['master', 'develop', 'feature', 'hotfix', 'support']
+```
+
+Without this configuration value you would have to do:
+
+
+```
+branches:
+  unstable:
+    regex: ...
+  feature:
+    source-branches: ['unstable', 'develop', 'feature', 'hotfix', 'support']
+  release:
+    source-branches: ['unstable', 'develop']
+  etc...
+```
+
 ### 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 +43,11 @@ branches:
     prevent-increment-of-merged-branch-version: true
     track-merge-target: false
     regex: releases?[/-]
+    source-branches:
+    - develop
+    - master
+    - support
+    - release
     tracks-release-branches: false
     is-release-branch: true
     is-mainline: false
@@ -39,6 +58,13 @@ 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 +76,13 @@ 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 +93,10 @@ branches:
     prevent-increment-of-merged-branch-version: false
     track-merge-target: false
     regex: hotfix(es)?[/-]
+    source-branches:
+    - develop
+    - master
+    - support
     tracks-release-branches: false
     is-release-branch: false
     is-mainline: false
@@ -70,18 +107,10 @@ 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

@@ -100,11 +100,12 @@ public void RegexIsRequired()
         tag: bugfix";
         SetupConfigFileContent(text);
         var ex = Should.Throw<GitVersionConfigurationException>(() => ConfigurationProvider.Provide(repoPath, fileSystem));
-        ex.Message.ShouldBe("Branch configuration 'bug' is missing required configuration 'regex'");
+        ex.Message.ShouldBe("Branch configuration 'bug' is missing required configuration 'regex'\n\n" +
+            "See http://gitversion.readthedocs.io/en/latest/configuration/ for more info");
     }
 
     [Test]
-    public void CanProvideConfigForNewBranch()
+    public void SourceBranchIsRequired()
     {
         const string text = @"
 next-version: 2.0.0
@@ -113,6 +114,22 @@ public void CanProvideConfigForNewBranch()
         regex: 'bug[/-]'
         tag: bugfix";
         SetupConfigFileContent(text);
+        var ex = Should.Throw<GitVersionConfigurationException>(() => ConfigurationProvider.Provide(repoPath, fileSystem));
+        ex.Message.ShouldBe("Branch configuration 'bug' is missing required configuration 'source-branches'\n\n" +
+            "See http://gitversion.readthedocs.io/en/latest/configuration/ for more info");
+    }
+
+    [Test]
+    public void CanProvideConfigForNewBranch()
+    {
+        const string text = @"
+next-version: 2.0.0
+branches:
+    bug:
+        regex: 'bug[/-]'
+        tag: bugfix
+        source-branches: []";
+        SetupConfigFileContent(text);
         var config = ConfigurationProvider.Provide(repoPath, fileSystem);
 
         config.Branches["bug"].Regex.ShouldBe("bug[/-]");

src/GitVersionCore.Tests/GitRepoMetadataProviderTests.cs

@@ -52,10 +52,10 @@ public void FindsCorrectMergeBaseForForwardMerge()
 
                 var develop = fixture.Repository.FindBranch("develop");
                 var release = fixture.Repository.FindBranch("release-2.0.0");
-                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(release, develop);
 
-                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(develop, release);
 
                 fixture.Repository.DumpGraph(Console.WriteLine);
@@ -109,10 +109,10 @@ public void FindsCorrectMergeBaseForForwardMergeMovesOn()
 
                 var develop = fixture.Repository.FindBranch("develop");
                 var release = fixture.Repository.FindBranch("release-2.0.0");
-                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(release, develop);
 
-                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(develop, release);
 
                 fixture.Repository.DumpGraph(Console.WriteLine);
@@ -184,10 +184,10 @@ public void FindsCorrectMergeBaseForMultipleForwardMerges()
 
                 var develop = fixture.Repository.FindBranch("develop");
                 var release = fixture.Repository.FindBranch("release-2.0.0");
-                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var releaseBranchMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(release, develop);
 
-                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository)
+                var developMergeBase = new GitRepoMetadataProvider(fixture.Repository, new Config())
                     .FindMergeBase(develop, release);
 
                 fixture.Repository.DumpGraph(Console.WriteLine);

src/GitVersionCore.Tests/GitVersionContextTests.cs

@@ -5,6 +5,7 @@
     using LibGit2Sharp;
     using NUnit.Framework;
     using Shouldly;
+    using System.Collections.Generic;
 
     public class GitVersionContextTests
     {
@@ -98,8 +99,8 @@ 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 List<string>() } },
+                    { "release", new BranchConfig { Increment = IncrementStrategy.Patch, Regex = "releases?[/-]", SourceBranches = new List<string>() } }
                 }
             }.ApplyDefaults();
 

src/GitVersionCore.Tests/IntegrationTests/DevelopScenarios.cs

@@ -3,6 +3,7 @@
 using GitVersionCore.Tests;
 using LibGit2Sharp;
 using NUnit.Framework;
+using System.Collections.Generic;
 
 [TestFixture]
 public class DevelopScenarios
@@ -64,7 +65,8 @@ public void CanChangeDevelopTagViaConfig()
                 {
                     "develop", new BranchConfig
                     {
-                        Tag = "alpha"
+                        Tag = "alpha",
+                        SourceBranches = new List<string>()
                     }
                 }
             }

src/GitVersionCore.Tests/IntegrationTests/FeatureBranchScenarios.cs

@@ -42,7 +42,16 @@ public void BranchCreatedAfterFastForwardMergeShouldInheritCorrectly()
         {
             Branches =
             {
-                { "unstable", new BranchConfig { Increment = IncrementStrategy.Minor, Regex = "unstable"} }
+                {
+                    "unstable",
+                    new BranchConfig
+                    {
+                        Increment = IncrementStrategy.Minor,
+                        Regex = "unstable",
+                        SourceBranches = new List<string>(),
+                        IsSourceBranchFor = new [] { "feature" }
+                    }
+                }
             }
         };
 

src/GitVersionCore.Tests/IntegrationTests/OtherScenarios.cs

@@ -5,6 +5,7 @@
     using GitVersion;
     using LibGit2Sharp;
     using NUnit.Framework;
+    using System.Collections.Generic;
 
     [TestFixture]
     public class OtherScenarios
@@ -56,7 +57,8 @@ public void AllowHavingMainInsteadOfMaster()
                 Tag = "useBranchName",
                 Increment = IncrementStrategy.Patch,
                 PreventIncrementOfMergedBranchVersion = true,
-                TrackMergeTarget = false
+                TrackMergeTarget = false,
+                SourceBranches = new List<string>()
             });
 
             using (var fixture = new EmptyRepositoryFixture())

src/GitVersionCore.Tests/IntegrationTests/ReleaseBranchScenarios.cs

@@ -418,7 +418,7 @@ public void CommitOnDevelop_AfterReleaseBranchMergeToDevelop_ShouldNotResetCount
             fixture.AssertFullSemver(config, "2.0.0-beta.5");
         }
     }
-  
+
     public void ReleaseBranchShouldUseBranchNameVersionDespiteBumpInPreviousCommit()
     {
         using (var fixture = new EmptyRepositoryFixture())
@@ -463,4 +463,53 @@ public void ReleaseBranchedAtCommitWithSemverMessageShouldUseBranchNameVersion()
             fixture.AssertFullSemver("2.0.0-beta.1+1");
         }
     }
+
+    [Test]
+    public void FeatureFromReleaseBranch_ShouldNotResetCount()
+    {
+        var config = new Config
+        {
+            VersioningMode = VersioningMode.ContinuousDeployment
+        };
+
+        using (var fixture = new EmptyRepositoryFixture())
+        {
+            fixture.Repository.MakeACommit("initial");
+            fixture.Repository.CreateBranch("develop");
+            Commands.Checkout(fixture.Repository, "develop");
+            fixture.Repository.CreateBranch("release-2.0.0");
+            Commands.Checkout(fixture.Repository, "release-2.0.0");
+            fixture.AssertFullSemver(config, "2.0.0-beta.0");
+
+            // Make some commits on release
+            fixture.Repository.MakeCommits(10);
+            fixture.AssertFullSemver(config, "2.0.0-beta.10");
+
+            // Create feature from release
+            fixture.BranchTo("feature/xxx");
+            fixture.Repository.MakeACommit("feature 1");
+            fixture.Repository.MakeACommit("feature 2");
+
+            // Check version on release
+            Commands.Checkout(fixture.Repository, "release-2.0.0");
+            fixture.AssertFullSemver(config, "2.0.0-beta.10");
+            fixture.Repository.MakeACommit("release 11");
+            fixture.AssertFullSemver(config, "2.0.0-beta.11");
+
+            // Make new commit on feature
+            Commands.Checkout(fixture.Repository, "feature/xxx");
+            fixture.Repository.MakeACommit("feature 3");
+
+            // Checkout to release (no new commits) 
+            Commands.Checkout(fixture.Repository, "release-2.0.0");
+            fixture.AssertFullSemver(config, "2.0.0-beta.11");
+
+            // Merge feature to release
+            fixture.Repository.MergeNoFF("feature/xxx", Generate.SignatureNow());
+            fixture.AssertFullSemver(config, "2.0.0-beta.15");
+
+            fixture.Repository.MakeACommit("release 13 - after feature merge");
+            fixture.AssertFullSemver(config, "2.0.0-beta.16");
+        }
+    }
 }