[Bug] Object reference not set to an instance of an object during versioning solving

[rafek1241]

Describe the bug
Branch version solving does not works

Expected Behavior

Correct composition of current version

Actual Behavior

System.NullReferenceException: Object reference not set to an instance of an object.
   at GitVersion.GitObject..ctor(GitObject innerGitObject) in D:\a\GitVersion\GitVersion\src\GitVersion.LibGit2Sharp\Git\GitObject.cs:line 12
   at GitVersion.Commit..ctor(Commit innerCommit) in D:\a\GitVersion\GitVersion\src\GitVersion.LibGit2Sharp\Git\Commit.cs:line 12
   at GitVersion.GitRepository.<>c__DisplayClass27_0.<FindMergeBase>b__0() in D:\a\GitVersion\GitVersion\src\GitVersion.LibGit2Sharp\Git\GitRepository.cs:line 61
   at Polly.Policy`1.<>c__DisplayClass11_0.<Execute>b__0(Context ctx, CancellationToken ct)
   at Polly.Retry.RetryEngine.Implementation[TResult](Func`3 action, Context context, CancellationToken cancellationToken, ExceptionPredicates shouldRetryExceptionPredicates, ResultPredicates`1 shouldRetryResultPredicates, Action`4 onRetry, Int32 permittedRetryCount, IEnumerable`1 sleepDurationsEnumerable, Func`4 sleepDurationProvider)
   at Polly.Retry.RetryPolicy`1.Implementation(Func`3 action, Context context, CancellationToken cancellationToken)
   at Polly.Policy`1.Execute(Func`3 action, Context context, CancellationToken cancellationToken)
   at Polly.Policy`1.Execute(Func`1 action)
   at GitVersion.Helpers.RetryAction`2.Execute(Func`1 operation) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Helpers\RetryAction.cs:line 35
   at GitVersion.GitRepository.FindMergeBase(ICommit commit, ICommit otherCommit) in D:\a\GitVersion\GitVersion\src\GitVersion.LibGit2Sharp\Git\GitRepository.cs:line 59
   at GitVersion.RepositoryStore.FindMergeBase(IBranch branch, IBranch otherBranch) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\RepositoryStore.cs:line 49
   at GitVersion.RepositoryStore.<>c__DisplayClass30_0.<GetMergeCommitsForBranch>b__2(IBranch otherBranch) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\RepositoryStore.cs:line 454
   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
   at System.Linq.Enumerable.WhereEnumerableIterator`1.ToArray()
   at System.Linq.OrderedEnumerable`1.ToList()
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at GitVersion.RepositoryStore.GetMergeCommitsForBranch(IBranch branch, Config configuration, IEnumerable`1 excludedBranches) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\RepositoryStore.cs:line 438
   at GitVersion.RepositoryStore.FindCommitBranchWasBranchedFrom(IBranch branch, Config configuration, IBranch[] excludedBranches) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\RepositoryStore.cs:line 320
   at GitVersion.Configuration.BranchConfigurationCalculator.InheritBranchConfiguration(IBranch targetBranch, BranchConfig branchConfiguration, ICommit currentCommit, Config configuration, IList`1 excludedInheritBranches)
   at GitVersion.Configuration.BranchConfigurationCalculator.GetBranchConfiguration(IBranch targetBranch, ICommit currentCommit, Config configuration, IList`1 excludedInheritBranches) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Configuration\BranchConfigurationCalculator.cs:line 44
   at GitVersion.GitVersionContextFactory.Create(GitVersionOptions gitVersionOptions) in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\GitVersionContextFactory.cs:line 39
   at GitVersion.GitVersionCoreModule.<>c__DisplayClass0_0.<RegisterTypes>b__1() in D:\a\GitVersion\GitVersion\src\GitVersion.Core\GitVersionCoreModule.cs:line 37
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.get_Value()
   at GitVersion.VersionCalculation.NextVersionCalculator.get_context() in D:\a\GitVersion\GitVersion\src\GitVersion.Core\VersionCalculation\NextVersionCalculator.cs:line 15
   at GitVersion.VersionCalculation.NextVersionCalculator.FindVersion() in D:\a\GitVersion\GitVersion\src\GitVersion.Core\VersionCalculation\NextVersionCalculator.cs:line 30
   at GitVersion.GitVersionCalculateTool.CalculateVersionVariables() in D:\a\GitVersion\GitVersion\src\GitVersion.Core\Core\GitVersionCalculateTool.cs:line 51
   at GitVersion.GitVersionExecutor.RunGitVersionTool(GitVersionOptions gitVersionOptions) in D:\a\GitVersion\GitVersion\src\GitVersion.App\GitVersionExecutor.cs:line 66
  INFO [01/18/22 15:50:05:06] Attempting to show the current git graph (please include in issue):
  INFO [01/18/22 15:50:05:06] Showing max of 100 commits
  INFO [01/18/22 15:50:05:13] * 0e9c7d4 49 minutes ago  (HEAD -> feature/XXX, tag: 1.0.0, origin/feature/XXX)

Steps to Reproduce

I used command line execution in my project directory:

dotnet.exe C:\Users\Admin\.nuget\packages\gitversion.tool\5.8.1\tools\net6.0\any\gitversion.dll /nocache

I tried as well with:

dotnet.exe C:\Users\Admin\.nuget\packages\gitversion.tool\5.8.1\tools\netcoreapp3.1\any\gitversion.dll /nocache
dotnet.exe C:\Users\Admin\.nuget\packages\gitversion.tool\5.8.1\tools\net5.0\any\gitversion.dll /nocache
dotnet.exe C:\Users\Admin\.nuget\packages\gitversion.tool\5.6.7\tools\net5.0\any\gitversion.dll /nocache

Your Environment

project that runs .net core 3.1

• Version Used:
• Operating System and version (Windows 10, Ubuntu 18.04): windows 10
• Link to your project: -
• Link to your CI build (if appropriate): -

Branch structure in my repository:

Rider:

[rafek1241]

Okay, rebase to master fixed the issue but it could be great to have such custom exception here to be more described.

[asbjornu]

If you are able to provide a public repository that reproduces this problem, it should be easy to fix. We don't want NullReferenceException to be thrown anywhere, as I completely agree they are obscure and unhelpful.

[rafek1241]

@asbjornu
It was my work repository. I will try to prepare some reproduction repository soon.

[rafek1241]

@asbjornu
Repository that reproduces the issue: https://github.com/rafek1241/gitversion-issue-2967-reproduction

[davidkeaveny]

I'm getting this issue with a private repo, so can help validate a fix if needed.

[asbjornu]

@davidkeaveny, can you please clone or fork GitVersion locally and run it against your repository to get a line numbered stack trace? If you're adventurous, it would be awesome if you found the source of the NRE and fixed it too.

[asbjornu]

I think I've managed to find the source of the issue you're experiencing, @rafek1241. As I'm not using Mainline myself, I'm not sure why this code is exactly as it is, but this line in RepositoryStore.GetMainlineBranches() is excluding all branches that don't have a MergeBase:

GitVersion/src/GitVersion.Core/Core/RepositoryStore.cs

Line 297 in 4d12ab0

.Where(a => a.MergeBase != null)

And for the reproduction repository you've provided, no branches have a MergeBase, causing the returned list to become empty. What's worrying is that while commenting that line out still fails on your repository, it fails no tests. So our test coverage on Mainline is obviously not great. 😬

What I think could work here is for Mainline to defer to BaseVersionCalculator if it's unable to find a suitable Mainline branch.

[asbjornu]

I think I've solved this in #3018. I still need to add a test and it should be good to go. I'm not yet confident that I'm able to reproduce the problem in a test, though.