fix(helm): support omitting image.registry in querydoc chart

[michaelspinks]

What

Make the querydoc (doc2vec) chart render a valid image reference when image.registry is left empty, so the registry can be omitted (e.g. to pull from Docker Hub or a mirror) without producing a leading-slash, unpullable reference.

Why

The image is built inline in templates/deployment.yaml:

image: "{{ .Values.image.registry }}/{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"

The / between registry and repository is written unconditionally. If image.registry is set to "", the result has a leading slash and is not a valid image reference, so the pod enters ImagePullBackOff:

/kagent-dev/doc2vec/mcp:1.1.10     # invalid reference

There is currently no way to omit the registry and let the container runtime resolve the repository against its default registry / a configured mirror.

Omitting the registry is a configuration users legitimately need:

• Docker Hub. A bare org/image reference resolves to Docker Hub, so users mirroring the image there want kagent-dev/doc2vec/mcp:tag, not ghcr.io/....
• Air-gapped / mirrored environments. Registry mirrors are configured at the container runtime, which rewrites the host — so chart values should carry only repository:tag.
• Registry rewriting. Admission controllers (e.g. Kyverno) prepend an internal registry, so users leave registry: "".
• Consistency. Other charts let you omit the registry; querydoc silently breaks with ImagePullBackOff, which reads like a bug.

Note: this is a different issue from the bundled-PostgreSQL registry//name:tag
double-slash bug (#2120). That helper uses a 3-segment registry/repository/name:tag
shape; querydoc uses a 2-segment registry/repository:tag shape with no separate
image name, so the failure here is a leading slash from an empty registry, not a
double slash from an empty repository. They are fixed independently.

Fix

Introduce a querydoc.image helper (the chart currently has none) that builds the path from non-empty segments via compact + join, and call it from the deployment:

{{- define "querydoc.image" -}}
{{- $img := .Values.image -}}
{{- $parts := compact (list $img.registry $img.repository) -}}
{{- printf "%s:%s" (join "/" $parts) ($img.tag | default .Chart.AppVersion) -}}
{{- end -}}

# templates/deployment.yaml
image: "{{ include "querydoc.image" . }}"

Rendered results:

registry	repository	tag	result
ghcr.io	kagent-dev/doc2vec/mcp	1.1.10	ghcr.io/kagent-dev/doc2vec/mcp:1.1.10 (unchanged)
ghcr.io	kagent-dev/doc2vec/mcp	v2.0.0	ghcr.io/kagent-dev/doc2vec/mcp:v2.0.0 (unchanged)
""	kagent-dev/doc2vec/mcp	1.1.10	kagent-dev/doc2vec/mcp:1.1.10 (fixed)

Tests

Added one case to helm/tools/querydoc/tests/deployment_test.yaml for the empty-registry path (developed test-first). The existing "should have correct container image" and "should use custom image tag when set" tests already guard the default and custom-tag paths, so no regression test was duplicated.

  - it: should omit empty registry segment in image
    template: deployment.yaml
    set:
      image:
        registry: ""
    asserts:
      - equal:
          path: spec.template.spec.containers[0].image
          value: kagent-dev/doc2vec/mcp:1.1.10
      - notMatchRegex:
          path: spec.template.spec.containers[0].image
          pattern: "^/"

The test fails without this change (/kagent-dev/doc2vec/mcp:1.1.10) and passes with it — revert the deployment.yaml/_helpers.tpl hunks to reproduce.

How to verify

make helm-tools                                     # generate querydoc Chart.yaml
helm unittest helm/tools/querydoc                   # full suite green (incl. new case)
helm lint helm/tools/querydoc

# test-independent reproduction:
helm template t helm/tools/querydoc --set image.registry="" | grep image:
# before: /kagent-dev/doc2vec/mcp:1.1.10
# after:  kagent-dev/doc2vec/mcp:1.1.10

Scope

Limited to the querydoc chart's image construction. Empty repository is not made valid here, because the repository carries the full image path and there is no separate image-name segment — omitting it leaves no image to pull. This PR only makes
image.registry optional.

Checklist

• Commit is DCO signed-off (git commit -s).
• helm unittest helm/tools/querydoc green; helm lint helm/tools/querydoc clean.
• Diff limited to templates/_helpers.tpl, templates/deployment.yaml, and
  tests/deployment_test.yaml (generated chart files excluded).
• Test fails without the fix, passes with it.

[Copilot]

Pull request overview

Updates the QueryDoc (doc2vec) Helm chart to render a valid container image reference when image.registry is empty, enabling users to omit the registry (e.g., Docker Hub/mirrors) without producing a leading-slash invalid image.

Changes:

• Add a querydoc.image helper that builds the image path from non-empty segments via compact + join.
• Switch templates/deployment.yaml to use the new helper for the container image.
• Add a Helm unittest case verifying that an empty image.registry does not produce a leading slash.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
helm/tools/querydoc/templates/_helpers.tpl	Adds querydoc.image helper to compose image references from optional segments.
helm/tools/querydoc/templates/deployment.yaml	Uses querydoc.image helper for the Deployment container image field.
helm/tools/querydoc/tests/deployment_test.yaml	Adds coverage for empty-registry image rendering (no leading slash).

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