Nerdbank.GitVersioning: GitException: An object of type commit could not be located at offset 60529

Nerdbank GitVersioning has been working for a couple of years with Gitlab (On-site hosted). We recently upgraded our .net projects from aspnet core 3.2 to .net 6. and Gitlab has not changed, but we are now seeing issues compiling.

We now see an exclamation icon in Visual Studio 2022 under the dependencies section for NerdBank.GitVersioning (3.5.109) We also get the following error when trying to compile:

Error MSB4018: The "Nerdbank.GitVersioning.Tasks.GetBuildVersion" task failed unexpectedly.
Nerdbank.GitVersioning.GitException: An object of type commit could not be located at offset 60529.
   at Nerdbank.GitVersioning.ManagedGit.GitPackReader.GetObject(GitPack pack, Stream stream, Int64 offset, String objectType, GitPackObjectType packObjectType)
   at Nerdbank.GitVersioning.ManagedGit.GitPack.GetObject(Int64 offset, String objectType)
   at Nerdbank.GitVersioning.ManagedGit.GitPack.TryGetObject(GitObjectId objectId, String objectType, Stream& value)
   at Nerdbank.GitVersioning.ManagedGit.GitRepository.TryGetObjectBySha(GitObjectId sha, String objectType, Stream& value)
   at Nerdbank.GitVersioning.ManagedGit.GitRepository.GetObjectBySha(GitObjectId sha, String objectType)
   at Nerdbank.GitVersioning.ManagedGit.GitRepository.GetCommit(GitObjectId sha, Boolean readAuthor)
   at Nerdbank.GitVersioning.Managed.GitExtensions.<GetCommitHeight>g__TryCalculateHeight|4_0(GitCommit commit, <>c__DisplayClass4_0& )
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetCommitHeight(GitRepository repository, GitCommit startingCommit, GitWalkTracker tracker, Func`2 continueStepping)
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetHeight(ManagedGitContext context, Func`2 continueStepping)
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetVersionHeight(ManagedGitContext context, Version baseVersion)
   at Nerdbank.GitVersioning.Managed.ManagedGitContext.CalculateVersionHeight(VersionOptions committedVersion, VersionOptions workingVersion)
   at Nerdbank.GitVersioning.VersionOracle..ctor(GitContext context, ICloudBuild cloudBuild, Nullable`1 overrideVersionHeightOffset)
   at Nerdbank.GitVersioning.Tasks.GetBuildVersion.ExecuteInner()
   at MSBuildExtensionTask.ContextAwareTask.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() (18, 6)

About this issue

Original URL
State: closed
Created 2 years ago
Comments: 19 (4 by maintainers)

Most upvoted comments

Your test .zip doesn’t repro the problem for me. But if it’s a Stream.Read problem as you say, that’s based more on buffer sizes and race conditions than anything specific in a repo. So I’ll look at the Stream.Read issue anyway. Can someone with a repro please try 3.6.42-alpha-g47b0d281e4 of the nuget package? You can find this version in our CI feed as described in our readme.

I’ve used the zip file that I previously shared. It was able to reproduce the problem with version 3.5.109, but 3.6.42-alpha-g47b0d281e4 seems to be working fine.

PS: I’m using dotnet 7.0.100-preview.6.22352.1 for my tests.

marcin-krystianc on Sep 20, 2022

Hi @AArnott,

I’ve managed to reproduce the problem by building a git repo with a synthetic commit history. It appears to me that managed engine has some problems with reading data from pack streams, but I didn’t get to the bottom of the problem yet. I can see in the debugger, that occasionally the read operation returns fewer bytes than requestd (read != toRead) in https://github.com/dotnet/Nerdbank.GitVersioning/blob/efc3b4c6f005530d0576d79f16ae93b3bb62d512/src/NerdBank.GitVersioning/ManagedGit/GitPackMemoryCacheStream.cs#L87

repo: TestNBGV.zip
error message:

The "Nerdbank.GitVersioning.Tasks.GetBuildVersion" task failed unexpectedly. [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
System.InvalidOperationException: Unable to get version from commit: 8136a6e4a3243b30b5e13878fa4916e2d624234f [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
 ---> System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.ManagedGit.GitTreeStreamingReader.FindNode(Stream stream, ReadOnlySpan`1 name) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.ManagedGit.GitRepository.GetTreeEntry(GitObjectId treeId, ReadOnlySpan`1 nodeName) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.ManagedVersionFile.GetVersion(GitCommit commit, String repoRelativeProjectDirectory, Dictionary`2 blobVersionCache, String& actualDirectory) [D:\workspace\CodeBin\global-packa
ges\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.GitWalkTracker.GetVersion(GitCommit commit) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   --- End of inner exception stack trace --- [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.GitWalkTracker.GetVersion(GitCommit commit) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.CommitMatchesVersion(GitCommit commit, SemanticVersion expectedVersion, Position comparisonPrecision, GitWalkTracker tracker) [D:\workspace\CodeBin\global-packag
es\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.<>c__DisplayClass1_0.<GetVersionHeight>b__0(GitCommit c) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.<GetCommitHeight>g__TryCalculateHeight|4_0(GitCommit commit, <>c__DisplayClass4_0&) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\Pr
ivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetCommitHeight(GitRepository repository, GitCommit startingCommit, GitWalkTracker tracker, Func`2 continueStepping) [D:\workspace\CodeBin\global-packages\nerdba
nk.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetHeight(ManagedGitContext context, Func`2 continueStepping) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.Managed.GitExtensions.GetVersionHeight(ManagedGitContext context, Version baseVersion) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.pro
j]
   at Nerdbank.GitVersioning.Managed.ManagedGitContext.CalculateVersionHeight(VersionOptions committedVersion, VersionOptions workingVersion) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\b
uild\PrivateP2PCaching.proj]
   at Nerdbank.GitVersioning.VersionOracle..ctor(GitContext context, ICloudBuild cloudBuild, Nullable`1 overrideVersionHeightOffset) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\Priv
ateP2PCaching.proj]
   at Nerdbank.GitVersioning.Tasks.GetBuildVersion.ExecuteInner() [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.pr
oj]
   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr) [D:\workspace\CodeBin\global-packages\nerdbank.gitversioning\3.5.109\build\PrivateP2PCaching.proj]
    0 Warning(s)
    1 Error(s)

marcin-krystianc on Sep 19, 2022

Thanks for the update. Maybe your repo was corrupted. But it’s still possible that in working with your repo that an object is created that we can’t parse (but git.exe can). If this re-surfaces for you again, please let us know.

AArnott on Sep 6, 2022

The version of VS you’re using is probably irrelevant, and what you do within the repo is certainly irrelevant. It’s all about the git.exe you used to clone and maintain the repo, and perhaps the git operations you perform within that repo. I couldn’t say why one clone you have works and another doesn’t other than to say that the git db has multiple ways to store objects (e.g. loose files vs. pack files) and only one of these ways is causing the trouble.

AArnott on Aug 26, 2022

Then I imagine it’s just a newer git version that changed the format, or perhaps a format that was always there but is unusual so our managed git implementation didn’t need to support it until now. Hopefully @qmfrederik (who wrote our managed git implementation) can investigate.

AArnott on Aug 24, 2022