Detect deprecated Parameter allowEmptyValue in 3.2 documents (AllowEmptyValueDeprecation rule)

CHANGELOG.md

@@ -14,6 +14,7 @@
   * `QuerystringBefore32`: detect Parameter `in: querystring` usage in pre-3.2 documents (3.2 addition; not validated at runtime)
   * `CookieStyleBefore32`: detect Parameter `style: cookie` usage in pre-3.2 documents (3.2 addition)
   * `ResponseSummaryBefore32`: detect Response Object `summary` usage in pre-3.2 documents (3.2 addition)
+  * `AllowEmptyValueDeprecation`: detect Parameter `allowEmptyValue` usage in 3.2 documents (deprecated in 3.2)
 * return nil from `request_operation` for a document without `paths` (3.1 allows a document with only `webhooks`), instead of raising `NoMethodError`
 * validate a value against a schema without `type`: keywords such as `properties`, `required`, `items`, `maxLength`, `enum` and `minimum` now apply when the value has the type the keyword is for, as in JSON Schema. They were all skipped before, so a value that breaks them may now fail validation
 * add `allow_3_2_features` config to apply OpenAPI 3.2 runtime behavior to documents that declare an earlier version (default `false`: pre-3.2 documents behave as before)

lib/openapi_parser/spec_validator.rb

@@ -33,6 +33,7 @@
 require_relative 'spec_validator/rules/querystring_before_32'
 require_relative 'spec_validator/rules/cookie_style_before_32'
 require_relative 'spec_validator/rules/response_summary_before_32'
+require_relative 'spec_validator/rules/allow_empty_value_deprecation'
 
 module OpenAPIParser
   class SpecViolationError < OpenAPIError
@@ -113,6 +114,7 @@ def rules
           Rules::QuerystringBefore32,
           Rules::CookieStyleBefore32,
           Rules::ResponseSummaryBefore32,
+          Rules::AllowEmptyValueDeprecation,
         ]
       end
   end

lib/openapi_parser/spec_validator/rules/allow_empty_value_deprecation.rb

@@ -0,0 +1,26 @@
+module OpenAPIParser
+  class SpecValidator
+    module Rules
+      # 3.2 deprecates `allowEmptyValue` on the Parameter Object (3.1 only
+      # called it NOT RECOMMENDED). The field is still allowed but
+      # discouraged, so we report it as a violation on 3.2 documents.
+      class AllowEmptyValueDeprecation < Rule
+        def check(root)
+          return [] unless version_at_least?('3.2')
+
+          violations = []
+          each_node(root, OpenAPIParser::Schemas::Parameter) do |node|
+            raw = node.raw_schema
+            next unless raw.is_a?(Hash) && raw.key?('allowEmptyValue')
+
+            violations << violation(
+              path: "#{node.object_reference}/allowEmptyValue",
+              message: '`allowEmptyValue` on a Parameter Object is deprecated in 3.2',
+            )
+          end
+          violations
+        end
+      end
+    end
+  end
+end

sig/openapi_parser/spec_validator.rbs

@@ -179,6 +179,10 @@ module OpenAPIParser
       class ResponseSummaryBefore32 < Rule
         def check: (OpenAPIParser::Schemas::OpenAPI root) -> Array[SpecValidator::SpecViolation]
       end
+
+      class AllowEmptyValueDeprecation < Rule
+        def check: (OpenAPIParser::Schemas::OpenAPI root) -> Array[SpecValidator::SpecViolation]
+      end
     end
   end
 

spec/data/openapi_3_2/allow_empty_value_31.yaml

@@ -0,0 +1,17 @@
+openapi: 3.1.0
+info:
+  title: Pet API
+  version: '1.0'
+paths:
+  /pets:
+    get:
+      summary: List pets
+      parameters:
+        - name: q
+          in: query
+          allowEmptyValue: true
+          schema:
+            type: string
+      responses:
+        '200':
+          description: OK

spec/data/openapi_3_2/allow_empty_value_32.yaml

@@ -0,0 +1,19 @@
+openapi: 3.2.0
+info:
+  title: Pet API
+  version: '1.0'
+paths:
+  /pets:
+    get:
+      summary: List pets
+      parameters:
+        # `allowEmptyValue` on a Parameter Object is deprecated in 3.2, so its
+        # use here is a spec violation.
+        - name: q
+          in: query
+          allowEmptyValue: true
+          schema:
+            type: string
+      responses:
+        '200':
+          description: OK

spec/openapi_parser/spec_validator/integration_3_2_spec.rb

@@ -248,4 +248,18 @@ def expect_clean(file)
       expect_clean('response_summary_32.yaml')
     end
   end
+
+  describe 'Parameter allowEmptyValue (deprecated in 3.2)' do
+    it 'warns on the version-mismatched document under :warn' do
+      expect_mismatch_warns('allow_empty_value_32.yaml', [:allow_empty_value_deprecation])
+    end
+
+    it 'raises SpecViolationError on the version-mismatched document under :raise' do
+      expect_mismatch_raises('allow_empty_value_32.yaml', [:allow_empty_value_deprecation])
+    end
+
+    it 'stays clean on the correctly-versioned document' do
+      expect_clean('allow_empty_value_31.yaml')
+    end
+  end
 end

spec/openapi_parser/spec_validator/rules/allow_empty_value_deprecation_spec.rb

@@ -0,0 +1,71 @@
+require_relative '../../../spec_helper'
+
+RSpec.describe 'OpenAPIParser::SpecValidator::Rules::AllowEmptyValueDeprecation' do
+  def base_doc(openapi_version_string, param)
+    {
+      'openapi' => openapi_version_string,
+      'info' => { 'title' => 'test', 'version' => '1.0' },
+      'paths' => {
+        '/pets' => {
+          'get' => {
+            'parameters' => [param],
+            'responses' => { '200' => { 'description' => 'OK' } },
+          },
+        },
+      },
+    }
+  end
+
+  def doc_with(openapi_version_string)
+    OpenAPIParser.parse(base_doc(openapi_version_string, { 'name' => 'q', 'in' => 'query', 'allowEmptyValue' => true, 'schema' => { 'type' => 'string' } }), strict_reference_validation: false)
+  end
+
+  def doc_without(openapi_version_string)
+    OpenAPIParser.parse(base_doc(openapi_version_string, { 'name' => 'q', 'in' => 'query', 'schema' => { 'type' => 'string' } }), strict_reference_validation: false)
+  end
+
+  def run_rule_for(root)
+    OpenAPIParser::SpecValidator::Rules::AllowEmptyValueDeprecation.new(root.openapi_version).check(root)
+  end
+
+  context 'with a 3.2 document using allowEmptyValue' do
+    it 'reports one violation pointing at the field' do
+      root = doc_with('3.2.0')
+      violations = run_rule_for(root)
+      expect(violations.size).to eq 1
+      expect(violations.first.path).to eq '#/paths/~1pets/get/parameters/0/allowEmptyValue'
+      expect(violations.first.rule_name).to eq :allow_empty_value_deprecation
+      expect(violations.first.message).to include('deprecated in 3.2')
+    end
+  end
+
+  context 'with a 3.2 document without allowEmptyValue' do
+    it 'reports no violation' do
+      expect(run_rule_for(doc_without('3.2.0'))).to eq []
+    end
+  end
+
+  context 'with a 3.1 document using allowEmptyValue' do
+    it 'reports no violation' do
+      expect(run_rule_for(doc_with('3.1.0'))).to eq []
+    end
+  end
+
+  context 'with a 3.1 document without allowEmptyValue' do
+    it 'reports no violation' do
+      expect(run_rule_for(doc_without('3.1.0'))).to eq []
+    end
+  end
+
+  context 'with a 3.0 document using allowEmptyValue' do
+    it 'reports no violation' do
+      expect(run_rule_for(doc_with('3.0.0'))).to eq []
+    end
+  end
+
+  context 'with a document whose openapi field is not a version' do
+    it 'reports no violation (rule skipped)' do
+      expect(run_rule_for(doc_with('not-a-version'))).to eq []
+    end
+  end
+end