fix: panic when validation unsupported file type

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added: New validation `expressionDoesNotUseClassicHistogramBucketOperations` to avoid queries fragile because of the classic histogram bucket operations.
   See the docs for more info [expressionDoesNotUseClassicHistogramBucketOperations](docs/validations.md#expressiondoesnotuseclassichistogrambucketoperations)
 - Changed: :warning: revert the ENV expansion in config file since it was breaking and caused issues (it was a stupid idea)
+- Fix: Avoid panic when validating unsupported file type and revert to previous behavior when any file was treated as a rule file regardless of the extension.
+       The only exception are `.jsonnet` files that are evaluated first.
 
 ## [3.4.0] - 2024-10-30
 - Fixed: :warning: Ignore white spaces around rule names in the `disabled_validation_rules` annotation CSV format (Thanks @jmichalek13 !)

Makefile

@@ -24,7 +24,7 @@ build:
 
 E2E_TESTS_VALIDATIONS_FILE := examples/validation.yaml
 E2E_TESTS_ADDITIONAL_VALIDATIONS_FILE := examples/additional-validation.yaml
-E2E_TESTS_RULES_FILES := examples/rules/*.yaml
+E2E_TESTS_RULES_FILES := examples/rules/*
 E2E_TESTS_DOCS_FILE_MD := examples/human_readable.md
 E2E_TESTS_DOCS_FILE_HTML := examples/human_readable.html
 

examples/rules/foo.jsonnet

@@ -0,0 +1,17 @@
+{
+  groups: [
+    {
+      name: 'foo',
+      limit: 1,
+      rules: [
+        {
+          alert: 'foo',
+          expr: |||
+            # ignore_validations: hasLabels,hasAnyOfAnnotations,hasAnnotations,hasAllowedLimit
+            1
+          |||,
+        },
+      ],
+    },
+  ],
+}

examples/rules/foo.rules

@@ -0,0 +1,6 @@
+# ignore_validations: hasLabels,hasAnyOfAnnotations,hasAnnotations,hasAllowedLimit
+groups:
+    - name: foo
+      rules:
+        - alert: foo
+          expr: 1

pkg/validate/validate.go

@@ -54,25 +54,26 @@ func Files(fileNames []string, validationRules []*validationrule.ValidationRule,
 		validationReport.FilesCount++
 		fileReport := validationReport.NewFileReport(fileName)
 		var yamlReader io.Reader
-		if strings.HasSuffix(fileName, ".yaml") || strings.HasSuffix(fileName, ".yml") {
-			var err error
-			yamlReader, err = os.Open(fileName)
+		switch {
+		case strings.HasSuffix(fileName, ".jsonnet"):
+			log.Debugf("evaluating jsonnet file %s", fileName)
+			jsonnetOutput, err := jsonnetVM.EvaluateFile(fileName)
 			if err != nil {
 				validationReport.Failed = true
 				fileReport.Valid = false
-				fileReport.Errors = []error{fmt.Errorf("cannot read file %s: %w", fileName, err)}
+				fileReport.Errors = []error{fmt.Errorf("cannot evaluate jsonnet file %s: %w", fileName, err)}
 				continue
 			}
-		} else if strings.HasSuffix(fileName, ".jsonnet") {
-			log.Debugf("evaluating jsonnet file %s", fileName)
-			jsonnetOutput, err := jsonnetVM.EvaluateFile(fileName)
+			yamlReader = strings.NewReader(jsonnetOutput)
+		default:
+			var err error
+			yamlReader, err = os.Open(fileName)
 			if err != nil {
 				validationReport.Failed = true
 				fileReport.Valid = false
-				fileReport.Errors = []error{fmt.Errorf("cannot evaluate jsonnet file %s: %w", fileName, err)}
+				fileReport.Errors = []error{fmt.Errorf("cannot read file %s: %w", fileName, err)}
 				continue
 			}
-			yamlReader = strings.NewReader(jsonnetOutput)
 		}
 		var rf unmarshaler.RulesFileWithComment
 		decoder := yaml.NewDecoder(yamlReader)