Add treatWarningsAsErrors option to ValidateTask in gradle plugin (#21626)

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/OpenApiGeneratorPlugin.kt

@@ -85,6 +85,7 @@ class OpenApiGeneratorPlugin : Plugin<Project> {
 
                     inputSpec.set(validate.inputSpec)
                     recommend.set(validate.recommend)
+                    treatWarningsAsErrors.set(validate.treatWarningsAsErrors)
                 }
 
                 register("openApiGenerate", GenerateTask::class.java).configure {

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/extensions/OpenApiGeneratorValidateExtension.kt

@@ -34,4 +34,9 @@ open class OpenApiGeneratorValidateExtension(project: Project) {
      * Whether to offer recommendations related to the validated specification document.
      */
     val recommend = project.objects.property<Boolean>().convention(true)
+
+    /**
+     * Whether to treat warnings as errors and fail the task.
+     */
+    val treatWarningsAsErrors = project.objects.property<Boolean>().convention(false)
 }

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/ValidateTask.kt

@@ -60,6 +60,10 @@ open class ValidateTask : DefaultTask() {
     @Input
     val recommend = project.objects.property<Boolean>().convention(true)
 
+    @Optional
+    @Input
+    val treatWarningsAsErrors = project.objects.property<Boolean>().convention(false)
+
     @get:Internal
     @set:Option(option = "input", description = "The input specification.")
     var input: String? = null
@@ -73,6 +77,7 @@ open class ValidateTask : DefaultTask() {
 
         val spec = inputSpec.get()
         val recommendations = recommend.get()
+        val failOnWarnings = treatWarningsAsErrors.get()
 
         logger.quiet("Validating spec $spec")
 
@@ -117,10 +122,16 @@ open class ValidateTask : DefaultTask() {
             }
 
             throw GradleException("Validation failed.")
-        } else {
-            out.withStyle(StyledTextOutput.Style.Success)
-            logger.debug("No error validations from swagger-parser or internal validations.")
-            out.println("Spec is valid.")
         }
+
+        if (failOnWarnings && validationResult.warnings.isNotEmpty()) {
+            out.withStyle(StyledTextOutput.Style.Error)
+            out.println("\nWarnings found in the spec and 'treatWarningsAsErrors' is enabled.\nFailing validation.\n")
+            throw GradleException("Validation failed due to warnings (treatWarningsAsErrors = true).")
+        }
+
+        out.withStyle(StyledTextOutput.Style.Success)
+        logger.debug("No error validations from swagger-parser or internal validations.")
+        out.println("Spec is valid.")
     }
 }

modules/openapi-generator-gradle-plugin/src/test/kotlin/ValidateTaskDslTest.kt

@@ -308,6 +308,48 @@ class ValidateTaskDslTest : TestBase() {
         )
     }
 
+    @Test(dataProvider = "gradle_version_provider")
+    fun `openApiValidate should fail with treatWarningsAsErrors on valid spec with warnings`(gradleVersion: String?) {
+        // Arrange
+        val projectFiles = mapOf(
+            "spec.yaml" to javaClass.classLoader.getResourceAsStream("specs/petstore-v3.0-recommend.yaml")
+        )
+
+        withProject(
+            """
+            | plugins {
+            |   id 'org.openapi.generator'
+            | }
+            |
+            | openApiValidate {
+            |   inputSpec = file("spec.yaml").absolutePath
+            |   treatWarningsAsErrors = true
+            | }
+        """.trimMargin(), projectFiles
+        )
+
+        // Act
+        val result = getGradleRunner(gradleVersion)
+            .withProjectDir(temp)
+            .withArguments("openApiValidate")
+            .withPluginClasspath()
+            .buildAndFail()
+
+        // Assert
+        assertTrue(
+            result.output.contains("Spec has issues or recommendations."),
+            "Unexpected/no message presented to the user for a valid spec."
+        )
+        assertTrue(
+            result.output.contains("Failing validation."),
+            "Expected validation to fail due to warnings, but no failure message was found."
+        )
+        assertEquals(
+            FAILED, result.task(":openApiValidate")?.outcome,
+            "Expected a failed run, but found ${result.task(":openApiValidate")?.outcome}"
+        )
+    }
+
     @Test(dataProvider = "gradle_version_provider")
     fun `openApiValidate should succeed without recommendations on valid spec`(gradleVersion: String?) {
         // Arrange