[Bug] GitVersion is crashing when trying to update AssemblyInfo.cs files.

Describe the bug Command used in Windows 10 command prompt or PowerShell as well as Azure DevOps build pipeline: gitversion /updateassemblyinfo GitVersion is crashing when trying to update AssemblyInfo.cs files.

Expected Behavior

I expected the version in the GitVersion.yml file to be applied to the AssemblyInfo.cs files since it is higher than the latest tag.

Actual Behavior

INFO [02/24/21 12:02:31:25] Working directory: C:\git\Upmc.ServiceBus.Common.V3
INFO [02/24/21 12:02:31:29] Project root is: C:\git\Upmc.ServiceBus.Common.V3\
INFO [02/24/21 12:02:31:29] DotGit directory is: C:\git\Upmc.ServiceBus.Common.V3\.git
INFO [02/24/21 12:02:31:34] Begin: Loading version variables from disk cache
  INFO [02/24/21 12:02:31:34] Begin: Deserializing version variables from cache file C:\git\Upmc.ServiceBus.Common.V3\.git\gitversion_cache\C39A271AF962B211C0A0EB6135B5B939FBB199F0.yml
    WARN [02/24/21 12:02:31:40] Unable to read cache file C:\git\Upmc.ServiceBus.Common.V3\.git\gitversion_cache\C39A271AF962B211C0A0EB6135B5B939FBB199F0.yml, deleting it.
    INFO [02/24/21 12:02:31:41] System.InvalidOperationException: Sequence contains no matching element
   at GitVersion.OutputVariables.VersionVariables.FromFile(String filePath, IFileSystem fileSystem, ILog log)
   at GitVersion.VersionCalculation.Cache.GitVersionCache.LoadVersionVariablesFromDiskCache(GitVersionCacheKey key)
  INFO [02/24/21 12:02:31:41] End: Deserializing version variables from cache file C:\git\Upmc.ServiceBus.Common.V3\.git\gitversion_cache\C39A271AF962B211C0A0EB6135B5B939FBB199F0.yml (Took: 72.49ms)
  INFO [02/24/21 12:02:31:41] End: Loading version variables from disk cache (Took: 73.39ms)
  INFO [02/24/21 12:02:31:45] Using latest commit on specified branch
  INFO [02/24/21 12:02:31:46] Begin: Attempting to inherit branch configuration from parent branch
    INFO [02/24/21 12:02:31:47] Begin: Finding branch source of 'feature/UpdateEventConvention'
      INFO [02/24/21 12:02:31:48] Begin: Finding merge base between 'feature/UpdateEventConvention' and 'develop'.
        INFO [02/24/21 12:02:31:49] Found merge base of e50099d Merged PR 40222: refactored multi-client code
        INFO [02/24/21 12:02:31:49] Merge base of feature/UpdateEventConvention' and 'develop is e50099d Merged PR 40222: refactored multi-client code
      INFO [02/24/21 12:02:31:49] End: Finding merge base between 'feature/UpdateEventConvention' and 'develop'. (Took: 12.31ms)
      INFO [02/24/21 12:02:31:49] Begin: Finding merge base between 'feature/UpdateEventConvention' and 'master'.
      INFO [02/24/21 12:02:31:50] End: Finding merge base between 'feature/UpdateEventConvention' and 'master'. (Took: 4.28ms)
    INFO [02/24/21 12:02:31:50] End: Finding branch source of 'feature/UpdateEventConvention' (Took: 27.41ms)
  INFO [02/24/21 12:02:31:50] End: Attempting to inherit branch configuration from parent branch (Took: 41.27ms)
  ERROR [02/24/21 12:02:31:50] An unexpected error occurred:
System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.)
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at GitVersion.GitObject..ctor(GitObject innerGitObject)
   at GitVersion.Commit..ctor(Commit innerCommit)
   at GitVersion.GitRepository.<>c__DisplayClass27_0.<FindMergeBase>b__0()
   at GitVersion.Helpers.OperationWithExponentialBackoff`2.ExecuteAsync()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at System.Threading.Tasks.Task`1.get_Result()
   at GitVersion.GitRepository.FindMergeBase(ICommit commit, ICommit otherCommit)
   at GitVersion.RepositoryStore.FindMergeBase(IBranch branch, IBranch otherBranch)
   at GitVersion.RepositoryStore.<>c__DisplayClass29_0.<GetMergeCommitsForBranch>b__2(IBranch otherBranch)
   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)
   at GitVersion.RepositoryStore.FindCommitBranchWasBranchedFrom(IBranch branch, Config configuration, IBranch[] excludedBranches)
   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)
   at GitVersion.GitVersionContextFactory.Create(GitVersionOptions gitVersionOptions)
   at GitVersion.GitVersionCoreModule.<>c__DisplayClass0_0.<RegisterTypes>b__3()
   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()
   at GitVersion.VersionCalculation.NextVersionCalculator.FindVersion()
   at GitVersion.GitVersionCalculateTool.CalculateVersionVariables()
   at GitVersion.GitVersionExecutor.RunGitVersionTool(GitVersionOptions gitVersionOptions)
  INFO [02/24/21 12:02:31:50] Attempting to show the current git graph (please include in issue):
  INFO [02/24/21 12:02:31:50] Showing max of 100 commits
  INFO [02/24/21 12:02:31:64] * d6747b0 4 hours ago  (HEAD -> feature/UpdateEventConvention, origin/feature/UpdateEventConvention)
*   e50099d 3 months ago  (origin/develop, origin/HEAD, develop)
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*   5409029 1 year ago
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* 63c548d 1 year, 1 month ago
| * bb73ddf 12 months ago  (origin/master, master)
| * 132ae1b 1 year, 1 month ago  (tag: 2.3.1)
| *   f41353f 1 year, 2 months ago  (tag: 2.3.0)
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[GitVersion.yml.txt](https://github.com/GitTools/GitVersion/files/6038051/GitVersion.yml.txt)

Possible Fix

Steps to Reproduce

I am not able to share the source code from our internal Git source repository because of intellectual property.

Context

We use GitVersion as part of our Azure DevOps build pipelines to assign the assembly version information at build time.

Your Environment

Azure DevOps (hosted) Classic Build Pipeline

• Version Used: 5.6.6+Branch.main.Sha.80adc3f3b8919b655adca7b796b273fb10478c3f
• Operating System and version (Windows 10 and Azure DevOps):
• Link to your project: (Private)
• Link to your CI build (if appropriate): (Private)

[SanjayGuntur]

I came across this issue as well, but on a different set of steps. I was experimenting with ways to limit git history to a particular folder by running git branch-filter command. Running GitVersion on the filtered repository worked with 5.5.0, but failed with 5.6.6, at the same place @robbrattonUPMC reported.

It is possible for a branch to have a different history than that of its parent branch, orphan branches for example.

Here is a simple powershell script that reproduces the problem.

# Create a folder that we can reproduce the issue in
$folder = "c:\temp\GitVersion-2605"
New-Item -ItemType Directory -Path $folder | Out-Null

# Init git on this folder
Set-Location $folder | Out-Null
git init

# Add a file and commit
"File on master branch" | Out-File -FilePath file-on-master.txt
git add file-on-master.txt
git commit -m "Commit on master"

# Ensure new and old version of GitVersion work
\Tools\GitVersion.CommandLine.5.5.0\Tools\GitVersion.exe /showvariable SemVer
\Tools\GitVersion.CommandLine.5.6.6\Tools\GitVersion.exe /showvariable SemVer

# Create an orphan branch
git checkout --orphan orphan

# Add a file and commit to the orphan branch
"File on orphan branch" | Out-File -FilePath file-on-orphan.txt
git add file-on-orphan.txt
git commit -a -m "Commit on orphan"

# Ensure new and old version of GitVersion work
\Tools\GitVersion.CommandLine.5.5.0\Tools\GitVersion.exe /showvariable SemVer
\Tools\GitVersion.CommandLine.5.6.6\Tools\GitVersion.exe /showvariable SemVer

I’m happy to fix and write tests for this issue, if this is identified as a bug, or as an improvement.

[JordanOberrathUPMC]

I was running into the same issue and discovered that it happened if any of the branches in the repository had no commits. In my case it was the Master branch, which was not initialized with a ReadMe.md. I noticed it because it failed on a pull request right where it was trying to find the merge base between the feature and master branch. So, my question is, how can I get the GitVersion.exe /updateassemblyinfo to only consider the branches relevant to the merge when determining the merge base, and to ignore all other branches?