fix: support staffbase-application Helm chart image field shape (#139)

* fix: auto-detect image field type to support staffbase-application chart

The staffbase-application Helm chart splits the image into a mapping:

  image:
    repository: registry.staffbase.com/sb-images/app
    tag: dev-abc123

When gitops-github-action writes the full URI as a scalar to
spec.values.workload.container.image, the kustomize patch replaces the
mapping with a string. The chart then renders 'image: :' — both
.image.repository and .image.tag resolve to empty.

Fix: before writing, read the type of the target field using yq.
- If the field is a mapping (!!map), write only INPUT_TAG to .field.tag
- Otherwise, write the full image URI as before (Apperator pattern)

Callers specifying spec.values.workload.container.image get the right
behaviour automatically based on what is already in their overlay file.
No changes to cicd.yml required.

Backwards compatible: all existing Apperator-style callers have scalar
image fields (!!str) and continue to receive the full URI unchanged.

Assisted-by: pi:claude-sonnet-4-5

* refactor: handle all image field shapes via explicit and auto-detection

Assisted-by: pi:claude-sonnet-4-5

Author: asadk23

scripts/lib/gitops-functions.sh

@@ -36,7 +36,17 @@ update_file() {
   echo "Check if path ${file} ${field} exists and get old current version"
   yq -e ."${field}" "${file}"
   echo "Run update ${file} ${field} ${image}"
-  yq -i ."${field}"=\""${image}"\" "${file}"
+  if [[ "${field}" == *.tag ]]; then
+    yq -i ".${field}=\"${INPUT_TAG}\"" "${file}"
+  else
+    local field_type
+    field_type=$(yq "(.${field} | type)" "${file}" 2>/dev/null || echo "!!null")
+    if [[ "${field_type}" == "!!map" ]] && yq -e ".${field}.tag" "${file}" > /dev/null 2>&1; then
+      yq -i ".${field}.tag=\"${INPUT_TAG}\"" "${file}"
+    else
+      yq -i ."${field}"=\""${image}"\" "${file}"
+    fi
+  fi
 
   echo "Writing deployment annotations to ${file}"
   yq -i '.metadata.annotations["deploy.staffbase.com/repositoryFullName"] = "'"${GITHUB_REPOSITORY}"'"' "${file}"

tests/fixtures/helmrelease.yaml

@@ -0,0 +1,13 @@
+apiVersion: helm.toolkit.fluxcd.io/v2
+kind: HelmRelease
+metadata:
+  name: my-service
+  namespace: my-service
+  annotations: {}
+spec:
+  values:
+    workload:
+      container:
+        image:
+          repository: registry.staffbase.com/sb-images/my-service
+          tag: placeholder

tests/lib-gitops-functions.bats

@@ -51,6 +51,38 @@ teardown() {
 
 # --- update_file ---
 
+@test "update_file writes full URI when field value is a scalar" {
+  cat > "${TEST_TEMP_DIR}/mocks/yq" << 'YQ_MOCK'
+#!/usr/bin/env bash
+echo "yq $*" >> "${MOCK_CALLS_DIR}/yq_calls.log"
+if [[ "$*" == *"| type"* ]]; then echo "!!str"; fi
+exit 0
+YQ_MOCK
+  chmod +x "${TEST_TEMP_DIR}/mocks/yq"
+  update_file "deployment.yaml" "spec.template.spec.containers.app.image" "$IMAGE"
+  grep -q "${IMAGE}" "${TEST_TEMP_DIR}/yq_calls.log"
+  ! grep -q ".tag=\"${INPUT_TAG}\"" "${TEST_TEMP_DIR}/yq_calls.log"
+}
+
+@test "update_file writes tag to .tag subfield when field is a map with tag property" {
+  cat > "${TEST_TEMP_DIR}/mocks/yq" << 'YQ_MOCK'
+#!/usr/bin/env bash
+echo "yq $*" >> "${MOCK_CALLS_DIR}/yq_calls.log"
+if [[ "$*" == *"| type"* ]]; then echo "!!map"; fi
+exit 0
+YQ_MOCK
+  chmod +x "${TEST_TEMP_DIR}/mocks/yq"
+  update_file "helmrelease.yaml" "spec.values.workload.container.image" "$IMAGE"
+  grep -q ".spec.values.workload.container.image.tag=\"${INPUT_TAG}\"" "${TEST_TEMP_DIR}/yq_calls.log"
+  ! grep -q "${IMAGE}" "${TEST_TEMP_DIR}/yq_calls.log"
+}
+
+@test "update_file writes tag only when field path ends with .tag" {
+  update_file "helmrelease.yaml" "spec.values.workload.container.image.tag" "$IMAGE"
+  grep -q ".spec.values.workload.container.image.tag=\"${INPUT_TAG}\"" "${TEST_TEMP_DIR}/yq_calls.log"
+  ! grep -q "${IMAGE}" "${TEST_TEMP_DIR}/yq_calls.log"
+}
+
 @test "update_file calls yq to check and update field" {
   update_file "deployment.yaml" "spec.image" "$IMAGE"
   assert [ -f "${TEST_TEMP_DIR}/yq_calls.log" ]