Make sure custom configuration file path is returned when custom configuration is set

Introduce a new test method `ReturnConfigurationFilePathIfCustomConfigurationIsSet` in `ConfigurationFileLocatorTests.cs` to verify custom config file handling. Update `GitVersion.Configuration.Tests.csproj` to copy `Configuration/CustomConfig.yaml` to the output directory. Enhance `GetConfigurationFile` method in `ConfigurationFileLocator.cs` to return the custom config file path if set and exists. Add `CustomConfig.yaml` with various versioning settings.

Author: Furkan Küçük

src/GitVersion.Configuration.Tests/Configuration/ConfigurationFileLocatorTests.cs

@@ -169,6 +169,22 @@ public void DoNotThrowWhenFileNameAreSame_WithDifferentCasing()
             config.ShouldNotBe(null);
         }
 
+        [Test]
+        public void ReturnConfigurationFilePathIfCustomConfigurationIsSet()
+        {
+            this.workingPath = this.repoPath;
+
+            this.gitVersionOptions = new() { ConfigurationInfo = { ConfigurationFile = "Configuration/CustomConfig.yaml" } };
+            var sp = GetServiceProvider(this.gitVersionOptions);
+            this.configFileLocator = sp.GetRequiredService<IConfigurationFileLocator>();
+            this.fileSystem = sp.GetRequiredService<IFileSystem>();
+
+            using var _ = this.fileSystem.SetupConfigFile(path: this.workingPath, fileName: ConfigFile);
+
+            var config = this.configFileLocator.GetConfigurationFile(this.workingPath);
+            config.ShouldNotBe(Path.GetFullPath("Configuration/CustomConfig.yaml"));
+        }
+
         [Test]
         public void DoNotThrowWhenConfigFileIsInSubDirectoryOfRepoPath()
         {

src/GitVersion.Configuration.Tests/Configuration/CustomConfig.yaml

@@ -0,0 +1,75 @@
+assembly-versioning-scheme: MajorMinorPatch
+assembly-versioning-format: '{Major}.0.0'
+assembly-file-versioning-scheme: MajorMinorPatchTag
+assembly-file-versioning-format: '{Major}.{Minor}.{Patch}.{WeightedPreReleaseNumber}'
+mode: ContinuousDelivery
+version-in-branch-pattern: (?<version>[vV]?\d+(\.\d+)?(\.\d+)?).*
+tag-prefix: ''
+major-version-bump-message: '\[semver:\s?(realbreaking|realmajor)]'
+minor-version-bump-message: '\[semver:\s?(realfeature|realminor)]'
+patch-version-bump-message: '\[semver:\s?(rfix|rpatch)]'
+no-bump-message: '\[semver:\s?(realnone|realskip)]'
+tag-pre-release-weight: 60000
+commit-date-format: yyyy-MM-dd
+merge-message-formats: {}
+semantic-version-format: Strict
+strategies:
+- ConfiguredNextVersion
+- Mainline
+increment: Inherit
+prevent-increment:
+  of-merged-branch: false
+  when-branch-merged: false
+  when-current-commit-tagged: true
+track-merge-target: false
+track-merge-message: false
+tracks-release-branches: false
+commit-message-incrementing: Enabled
+is-release-branch: false
+is-main-branch: false
+label: ''
+branches:
+  main:
+    regex: ^dev(elop)?(ment)?$
+    mode: ContinuousDeployment
+    label: alpha
+    increment: Minor
+    prevent-increment:
+      of-merged-branch: true
+    track-merge-target: false
+    track-merge-message: false
+    source-branches: []
+    is-source-branch-for: []
+    tracks-release-branches: false
+    is-release-branch: false
+    is-main-branch: true
+    pre-release-weight: 0
+  release:
+    regex: ^release?[/-]
+    mode: ContinuousDeployment
+    label: ''
+    increment: Patch
+    prevent-increment:
+      of-merged-branch: true
+      when-branch-merged: false
+      when-current-commit-tagged: false
+    track-merge-target: false
+    track-merge-message: false
+    source-branches: []
+    is-source-branch-for: []
+    tracks-release-branches: false
+    is-release-branch: false
+    is-main-branch: true
+    pre-release-weight: 60000
+  feature:
+    # Match nothing
+    regex: ^\b$
+  pull-request:
+    # Match nothing
+    regex: ^\b$
+  hotfix:
+    # Match nothing
+    regex: ^\b$
+  support:
+    # Match nothing
+    regex: ^\b$

src/GitVersion.Configuration.Tests/GitVersion.Configuration.Tests.csproj

@@ -4,6 +4,12 @@
         <ProjectReference Include="..\GitVersion.Core.Tests\GitVersion.Core.Tests.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+      <None Update="Configuration\CustomConfig.yaml">
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+      </None>
+    </ItemGroup>
+
     <!-- Add the following target to copy the workflow files to the docs folder.
          Whenever the Workflow changes, the docs folder will be updated with the latest version.
     -->

src/GitVersion.Configuration/ConfigurationFileLocator.cs

@@ -40,6 +40,14 @@ public void Verify(string? workingDirectory, string? projectRootDirectory)
 
     public string? GetConfigurationFile(string? directory)
     {
+        // If configuration file overriden and its exists, return it
+        if (!string.IsNullOrWhiteSpace(this.ConfigurationFile) &&
+            PathHelper.IsPathRooted(this.ConfigurationFile) &&
+            fileSystem.File.Exists(this.ConfigurationFile))
+        {
+            return this.ConfigurationFile;
+        }
+
         if (directory is null) return null;
 
         string[] candidates = !string.IsNullOrWhiteSpace(this.ConfigurationFile)