feat: add lint_config input for custom yamllint rules

.github/workflows/test-action.yml

@@ -111,3 +111,65 @@ jobs:
     - name: Run chart-testing (install)
       if: steps.list-changed.outputs.changed == 'true'
       run: ct install --chart-dirs=testdata --target-branch ${{ github.event.repository.default_branch }}
+
+  test_ct_action_with_lint_config:
+    runs-on: ubuntu-latest
+
+    name: run action with a custom yamllint config
+    steps:
+    - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+    - name: Set up Helm
+      uses: azure/setup-helm@9bc31f4ebc9c6b171d7bfbaa5d006ae7abdb4310 # v5.0.1
+      with:
+        version: v3.17.0
+
+    - name: Install chart-testing
+      uses: ./
+
+    - name: Run chart-testing (lint) with the default config
+      run: ct lint --charts testdata/simple-deployment --check-version-increment=false --validate-maintainers=false
+
+    - name: Install chart-testing with lint_config
+      uses: ./
+      with:
+        lint_config: testdata/custom-lintconf.yaml
+
+    - name: Check CT_LINT_CONF
+      run: |
+        if [[ "${CT_LINT_CONF}" != "$(realpath testdata/custom-lintconf.yaml)" ]]; then
+          echo "CT_LINT_CONF should point to testdata/custom-lintconf.yaml, got '${CT_LINT_CONF}'"
+          exit 1
+        fi
+      shell: bash
+
+    - name: Run chart-testing (lint) with the custom config
+      run: |
+        log="${RUNNER_TEMP}/ct-lint.log"
+        if ct lint --charts testdata/simple-deployment --check-version-increment=false --validate-maintainers=false > "${log}" 2>&1; then
+          cat "${log}"
+          echo 'ct lint should fail on the document-start rule from lint_config'
+          exit 1
+        fi
+        if ! grep -q 'missing document start' "${log}"; then
+          cat "${log}"
+          echo 'ct lint failed, but not because of lint_config'
+          exit 1
+        fi
+        echo 'ct lint failed on the document-start rule from lint_config, as expected'
+      shell: bash
+
+    - name: Install chart-testing with a missing lint_config
+      id: missing_lint_config
+      continue-on-error: true
+      uses: ./
+      with:
+        lint_config: testdata/does-not-exist.yaml
+
+    - name: Check the missing lint_config failed
+      run: |
+        if [[ '${{ steps.missing_lint_config.outcome }}' != 'failure' ]]; then
+          echo 'a missing lint_config should fail the action'
+          exit 1
+        fi
+      shell: bash

README.md

@@ -18,6 +18,7 @@ For more information on inputs, see the [API Documentation](https://developer.gi
 - `version`: The chart-testing version to install (default: `3.14.0`)
 - `yamllint_version`: The `yamllint` version to install (default: `1.33.0`)
 - `yamale_version`: The `yamale` version to install (default: `6.0.0`)
+- `lint_config`: Path to a custom yamllint config file. If set, `ct lint` uses it instead of the default `lintconf.yaml` (default: none)
 
 ### Example Workflow
 

action.yml

@@ -25,6 +25,10 @@ inputs:
     description: "GitHub token for authenticating with the GitHub API (default: github.token)"
     required: false
     default: ${{ github.token }}
+  lint_config:
+    description: "Path to a custom yamllint config file. If set, ct lint uses it instead of the default lintconf.yaml."
+    required: false
+    default: ''
 runs:
   using: composite
   steps:
@@ -40,3 +44,14 @@ runs:
             --yamllint-version ${{ inputs.yamllint_version }} \
             --yamale-version ${{ inputs.yamale_version }}
       shell: bash
+    - if: inputs.lint_config != ''
+      env:
+        LINT_CONFIG: ${{ inputs.lint_config }}
+      run: |
+        if [[ ! -f "${LINT_CONFIG}" ]]; then
+          echo "::error::lint_config file not found: ${LINT_CONFIG}"
+          exit 1
+        fi
+        echo "CT_LINT_CONF=$(realpath "${LINT_CONFIG}")" >> "${GITHUB_ENV}"
+        echo "Using custom yamllint config: ${LINT_CONFIG}"
+      shell: bash

testdata/custom-lintconf.yaml

@@ -0,0 +1,8 @@
+---
+# Used by the lint_config test in .github/workflows/test-action.yml.
+# The default ct config disables document-start, and
+# simple-deployment/Chart.yaml has no "---", so ct lint only fails
+# when this file is the one in use.
+rules:
+  document-start:
+    present: true