Invalid gitops-engine version in v3.4.1

[chengfang]

Checklist:

• I've searched in the docs and FAQ for my answer: https://bit.ly/argocd-faq.
• I've included steps to reproduce the bug.
• I've pasted the output of argocd version.

Describe the bug

When upgrading argocd-image-updater to use argo-cd v3.4.1, it failed to resolve gitops-engine version

go mod tidy
go: downloading github.com/argoproj/argo-cd/gitops-engine v0.7.1-0.20250908182407-97ad5b59a627
go: downloading google.golang.org/genproto/googleapis/api v0.0.0-20260209200024-4cfbd4190f57
go: downloading go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0
go: downloading google.golang.org/genproto/googleapis/rpc v0.0.0-20260226221140-a57be14db171
go: downloading go.opentelemetry.io/otel/sdk/metric v1.42.0
go: downloading github.com/go-openapi/testify/v2 v2.4.0
go: downloading go.opentelemetry.io/otel/metric v1.42.0
go: downloading go.opentelemetry.io/otel/trace v1.42.0
go: downloading go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.42.0
go: downloading go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0
go: downloading go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.42.0
go: downloading go.opentelemetry.io/proto/otlp v1.9.0
go: downloading github.com/klauspost/cpuid/v2 v2.2.4
go: github.com/argoproj-labs/argocd-image-updater/cmd imports
	github.com/argoproj/argo-cd/v3/pkg/apis/application/v1alpha1 imports
	github.com/argoproj/argo-cd/gitops-engine/pkg/health: github.com/argoproj/argo-cd/gitops-engine@v0.7.1-0.20250908182407-97ad5b59a627: invalid version: missing github.com/argoproj/argo-cd/gitops-engine/go.mod at revision 97ad5b59a627
go: github.com/argoproj-labs/argocd-image-updater/cmd imports
	github.com/argoproj/argo-cd/v3/pkg/apis/application/v1alpha1 imports
	github.com/argoproj/argo-cd/gitops-engine/pkg/sync/common: github.com/argoproj/argo-cd/gitops-engine@v0.7.1-0.20250908182407-97ad5b59a627: invalid version: missing github.com/argoproj/argo-cd/gitops-engine/go.mod at revision 97ad5b59a627
go: github.com/argoproj-labs/argocd-image-updater/cmd imports
	github.com/argoproj/argo-cd/v3/pkg/apis/application/v1alpha1 imports
	github.com/argoproj/argo-cd/gitops-engine/pkg/utils/kube: github.com/argoproj/argo-cd/gitops-engine@v0.7.1-0.20250908182407-97ad5b59a627: invalid version: missing github.com/argoproj/argo-cd/gitops-engine/go.mod at revision 97ad5b59a627

In go.mod, the gitops-engine version in v3.4.1 is declared as:

github.com/argoproj/argo-cd/gitops-engine v0.7.1-0.20250908182407-97ad5b59a627

That version was probably from the standalone gitops-engine, before it was merged back into argo-cd. So it's invalid for the new module path argocd/gitops-engine.

This works with argo-cd itself since this dep is later replaced with in-repo path. But for downstream consumer of v3.4.1, the upgrade will fail with above error.

The workaround is to add a replace entry in any downstream projects that depend on argo-cd and gitops-engine. See https://github.com/argoproj-labs/argocd-image-updater/pull/1636/changes#diff-33ef32bf6c23acb95f5902d7097b7a1d5128ca061167ec0716715b0b9eeaa5f6

It will be good to tag and release gitops-engine as part of the argo-cd release, and reference that tag by argo-cd and downstream projects.

To Reproduce

Expected behavior

consumer projects should be able to upgrade to argo-cd 3.4.1 and the corresponding gitops-engine smoothly.

Screenshots

Version

Paste the output from `argocd version` here.
v3.4.1

Logs

Paste any relevant application logs here.

[rumstead]

Date	Event
Sep 24, 2025	gitops-engine physically merged into argo-cd (PR #24710), but gitops-engine/go.mod still declared module github.com/argoproj/gitops-engine.
Oct 6, 2025	PR #24841 reverted go.work. With some feedback as to why.
Sep 2025 – Feb 2026	argo-cd’s go.mod used require github.com/argoproj/gitops-engine ... with replace github.com/argoproj/gitops-engine => ./gitops-engine. The Go module proxy continued serving new commits under the old module name because gitops-engine/go.mod had not changed.
Feb 12, 2026	PR #26407 renamed the module to github.com/argoproj/argo-cd/gitops-engine, the breaking change.
v3.3.9 (released before Feb 2026)	Uses github.com/argoproj/gitops-engine (old module path).
v3.4.1 (released after Feb 2026)	Uses github.com/argoproj/argo-cd/gitops-engine (new module path).

So I am pretty sure by us not updating gitops-engine in the go.mod we are breaking the ability for developers to use it as a go module.

So i think we really have 3 options.

1. publish release tags like gitops-engine/vX.Y.Z for each release and bump them in the go.mod for each release
   • this is more or less how k8s does it.
   • we either have to independently version gitops-engine or if we wanted to keep it in sync with the Argo CD version we would need to update it to github.com/argoproj/argo-cd/v3/gitops-engine
2. bump github.com/argoproj/argo-cd/gitops-engine to a resolvable version eg v0.0.0-20260212142940-0cdd44bda77a, ideally current latest and cut patches. Remember to do this in some cadance
3. move to go.work and acknowledge some of the issues that @alexmt highlighted in chore: use go mod override instead of go.work #24841 but it doesn't provide much benefit since it just removes the need for replace but we still have to manage the gitops-engine dependency in the go.mod.

I lean towards 1 but that will require changes to how we do release currently.

[ppapapetrou76]

@rumstead great analysis and I'm sold for the first option - more clear and concise and as you already wrote it's the k8s way

[rumstead]

Yea another drawback is we either update gitops-engine to v3 or handle versioning separately.

eg github.com/argoproj/argo-cd/v3/gitops-engine

[reggie-k]

Yeah I like the 1st option too.