[ISSUE]: High memory usage

[pvanbuijtene]

Prerequisites

• I have written a descriptive issue title
• I have searched issues to ensure it has not already been reported

GitVersion package

GitVersion.Tool

GitVersion version

6.4

Operating system

Windows, Linux

What are you seeing?

Running the dotnet-gitversion tool with default configuration results in high memory usage of around 10GB, this is on a repository with 25k commits.

This amount is a bit too much for our build agents resulting in builds to fail... and is also a bit unexpectedly high.

PR with investigation is on it's way...

What is expected?

A more reasonable memory footprint of a few 100MBs would be reasonable I think in this case.

Steps to Reproduce

Looking into anonymizing the private repository.

RepositoryFixture Test

No response

Output log or link to your CI build (if appropriate).

[arturcic]

Is it a project you can share with us?

[pvanbuijtene]

It's an internal project, so can not directly share it.
I'm looking into git fast-export --anonymize to see if I can share it some how.

[arturcic]

that would be really useful.

[pvanbuijtene]

I'm afraid it's gong to be difficult, it's not possible to preserve the tags.
Some quick tests with git filter-repo also didn't result in something which can be shared to reproduce the problem.

Here's a redacted log for now: main.log.txt

The main things I noticed:

• The .ToArray() here causes large chucks of memory to be allocated.
• TaggedSemanticVersions.OfReleaseBranches seems to trigger the high memory usage, the other strategies operate at reasonable memory usage of ~400MB.

[AlexandreHetu]

We just setup an old large repo with GitVersion and are seeing a similar issue. GitVersion peeks at 8.2GB of memory usage when running with the default config.

I'll see if I can anonymize our repo here too.

[arturcic]

• The .ToArray() here causes large chucks of memory to be allocated.

Ideally we should use something like Span so that we do not allocate, and I suspect not only in that location.

[arturcic]

Hey @AlexandreHetu @pvanbuijtene I pushed a branch and a console app here https://github.com/GitTools/GitVersion/tree/anonymize/src/Anonymize which could be used to copy a repo to an anonymized repo. The console app is basically recreating the repository with new commits without blobs, keeping the message, branch name and tags. There are 3 methods which you can extend with your own transformation/anonymization logic. Hope this helps to create the anonymized version of your repo that you can shared with us.

Your source repo needs to have all the tags and branches locally fetched. You can use this script

# Clone repo
git clone --mirror https://github.com/{org}/{repo}.git repo/.git

# Change into repo directory
cd repo

# Update git config
git config --unset core.bare

# Checkout main or maste branch
git checkout main

[asbjornu]

Ideally we should use something like Span so that we do not allocate, and I suspect not only in that location.

Indeed, that could potentially save a lot of memory (and CPU).

[pvanbuijtene]

Just tried the anonymized repo and it worked as expected, fast and didn't even have time to check the memory usage when launched from a terminal.

Could it maybe have something to do with the amount of files and folders, it's quite large 😬
The main branch has almost 100k~files & 65k directories.

[arturcic]

Just tried the anonymized repo

Did you use the anonymizer branch and tool I shared or you created it in a different way

[pvanbuijtene]

I used the anonymizer tool you shared from this repo.

[arturcic]

I used the anonymizer tool you shared from this repo.

Did you need to customize the transformation methods? is the GitVersion tool returning the same version when it runs on the original and anonymized repositories?

[pvanbuijtene]

No changes just build and run, the output is nearly identical.
Original:

{
  "AssemblySemFileVer": "3.8.0.0",
  "AssemblySemVer": "3.8.0.0",
  "BranchName": "develop",
  "BuildMetaData": null,
  "CommitDate": "2025-09-26",
  "CommitsSinceVersionSource": 61,
  "EscapedBranchName": "develop",
  "FullBuildMetaData": "Branch.develop.Sha.7061ed403541e91310376ccbe5e09222ee35c61d",
  "FullSemVer": "3.8.0-alpha.61",
  "InformationalVersion": "3.8.0-alpha.61+Branch.develop.Sha.7061ed403541e91310376ccbe5e09222ee35c61d",
  "Major": 3,
  "MajorMinorPatch": "3.8.0",
  "Minor": 8,
  "Patch": 0,
  "PreReleaseLabel": "alpha",
  "PreReleaseLabelWithDash": "-alpha",
  "PreReleaseNumber": 61,
  "PreReleaseTag": "alpha.61",
  "PreReleaseTagWithDash": "-alpha.61",
  "SemVer": "3.8.0-alpha.61",
  "Sha": "7061ed403541e91310376ccbe5e09222ee35c61d",
  "ShortSha": "7061ed4",
  "UncommittedChanges": 3,
  "VersionSourceSha": "9575b432bc79d20c9f3e69d69288f41cf980a9dd",
  "WeightedPreReleaseNumber": 61
}

Anonimzed

{
  "AssemblySemFileVer": "3.8.0.0",
  "AssemblySemVer": "3.8.0.0",
  "BranchName": "develop",
  "BuildMetaData": null,
  "CommitDate": "2025-09-26",
  "CommitsSinceVersionSource": 61,
  "EscapedBranchName": "develop",
  "FullBuildMetaData": "Branch.develop.Sha.a0d899451bd6ed78166f7e9ba52898f077172594",
  "FullSemVer": "3.8.0-alpha.61",
  "InformationalVersion": "3.8.0-alpha.61+Branch.develop.Sha.a0d899451bd6ed78166f7e9ba52898f077172594",
  "Major": 3,
  "MajorMinorPatch": "3.8.0",
  "Minor": 8,
  "Patch": 0,
  "PreReleaseLabel": "alpha",
  "PreReleaseLabelWithDash": "-alpha",
  "PreReleaseNumber": 61,
  "PreReleaseTag": "alpha.61",
  "PreReleaseTagWithDash": "-alpha.61",
  "SemVer": "3.8.0-alpha.61",
  "Sha": "a0d899451bd6ed78166f7e9ba52898f077172594",
  "ShortSha": "a0d8994",
  "UncommittedChanges": 0,
  "VersionSourceSha": "a7225d31d7b0615278c0500fe80c2c0110d4a662",
  "WeightedPreReleaseNumber": 61
}

I'm a bit limited in time now, but will run it again and compare the logs later today.