Add exhaustiveness check for config validation

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/AllRulesConfig.kt

@@ -1,6 +1,8 @@
 package io.gitlab.arturbosch.detekt.core.config
 
 import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.core.config.validation.ValidatableConfiguration
+import io.gitlab.arturbosch.detekt.core.config.validation.validateConfig
 
 @Suppress("UNCHECKED_CAST")
 internal data class AllRulesConfig(

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/CompositeConfig.kt

@@ -2,6 +2,8 @@ package io.gitlab.arturbosch.detekt.core.config
 
 import io.gitlab.arturbosch.detekt.api.Config
 import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.validation.ValidatableConfiguration
+import io.gitlab.arturbosch.detekt.core.config.validation.validateConfig
 
 /**
  * Wraps two different configuration which should be considered when retrieving properties.

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DisabledAutoCorrectConfig.kt

@@ -2,6 +2,8 @@ package io.gitlab.arturbosch.detekt.core.config
 
 import io.gitlab.arturbosch.detekt.api.Config
 import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.validation.ValidatableConfiguration
+import io.gitlab.arturbosch.detekt.core.config.validation.validateConfig
 
 @Suppress("UNCHECKED_CAST")
 class DisabledAutoCorrectConfig(private val wrapped: Config) : Config, ValidatableConfiguration {

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/YamlConfig.kt

@@ -5,6 +5,8 @@ package io.gitlab.arturbosch.detekt.core.config
 import io.gitlab.arturbosch.detekt.api.Config
 import io.gitlab.arturbosch.detekt.api.Config.Companion.CONFIG_SEPARATOR
 import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.validation.ValidatableConfiguration
+import io.gitlab.arturbosch.detekt.core.config.validation.validateConfig
 import org.yaml.snakeyaml.Yaml
 import java.io.Reader
 import java.nio.file.Path

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidator.kt

@@ -0,0 +1,28 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.ConfigValidator
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+
+internal abstract class AbstractYamlConfigValidator : ConfigValidator {
+
+    override fun validate(config: Config): Collection<Notification> {
+        require(config is YamlConfig) {
+            val yamlConfigClass = YamlConfig::class.simpleName
+            val actualClass = config.javaClass.simpleName
+
+            "Only supported config is the $yamlConfigClass. Actual type is $actualClass"
+        }
+        val settings = ValidationSettings(
+            config.subConfig("config").valueOrDefault("checkExhaustiveness", false),
+        )
+
+        return validate(config, settings)
+    }
+
+    abstract fun validate(
+        configToValidate: YamlConfig,
+        settings: ValidationSettings
+    ): Collection<Notification>
+}

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ConfigValidation.kt

@@ -0,0 +1,118 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.github.detekt.tooling.api.InvalidConfig
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.ConfigValidator
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.api.Notification.Level
+import io.gitlab.arturbosch.detekt.api.internal.SimpleNotification
+import io.gitlab.arturbosch.detekt.core.NL
+import io.gitlab.arturbosch.detekt.core.ProcessingSettings
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import io.gitlab.arturbosch.detekt.core.extensions.loadExtensions
+import io.gitlab.arturbosch.detekt.core.reporting.red
+import io.gitlab.arturbosch.detekt.core.reporting.yellow
+
+/**
+ * Known existing properties on rule's which my be absent in the default-detekt-config.yml.
+ *
+ * We need to predefine them as the user may not have already declared an 'config'-block
+ * in the configuration and we want to validate the config by default.
+ */
+internal val DEFAULT_PROPERTY_EXCLUDES = setOf(
+    ".*>excludes",
+    ".*>includes",
+    ".*>active",
+    ".*>.*>excludes",
+    ".*>.*>includes",
+    ".*>.*>active",
+    ".*>.*>autoCorrect",
+    ".*>severity",
+    ".*>.*>severity",
+    "build>weights.*",
+    ".*>.*>ignoreAnnotated",
+    ".*>.*>ignoreFunction",
+).joinToString(",")
+
+internal fun checkConfiguration(settings: ProcessingSettings, baseline: Config) {
+    var shouldValidate = settings.spec.configSpec.shouldValidateBeforeAnalysis
+    if (shouldValidate == null) {
+        val props = settings.config.subConfig("config")
+        shouldValidate = props.valueOrDefault("validation", true)
+    }
+    if (shouldValidate) {
+        val validators =
+            loadExtensions<ConfigValidator>(settings) + DefaultPropertiesConfigValidator(settings, baseline)
+        val notifications = validators.flatMap { it.validate(settings.config) }
+        notifications.map(Notification::message).forEach(settings::info)
+        val errors = notifications.filter(Notification::isError)
+        if (errors.isNotEmpty()) {
+            val problems = notifications.joinToString(NL) { "\t- ${it.renderMessage()}" }
+            val propsString = if (errors.size == 1) "property" else "properties"
+            val title = "Run failed with ${errors.size} invalid config $propsString.".red()
+            throw InvalidConfig("$title$NL$problems")
+        }
+    }
+}
+
+internal fun validateConfig(
+    config: Config,
+    baseline: Config,
+    excludePatterns: Set<Regex>
+): List<Notification> {
+    require(baseline != Config.empty) { "Cannot validate configuration based on an empty baseline config." }
+    require(baseline is YamlConfig) {
+        val yamlConfigClass = YamlConfig::class.simpleName
+        val actualClass = baseline.javaClass.simpleName
+
+        "Only supported baseline config is the $yamlConfigClass. Actual type is $actualClass"
+    }
+
+    if (config == Config.empty) {
+        return emptyList()
+    }
+
+    return when (config) {
+        is YamlConfig -> validateYamlConfig(config, baseline, excludePatterns)
+        is ValidatableConfiguration -> config.validate(baseline, excludePatterns)
+        else -> error("Unsupported config type for validation: '${config::class}'.")
+    }
+}
+
+private fun validateYamlConfig(
+    configToValidate: YamlConfig,
+    baseline: YamlConfig,
+    excludePatterns: Set<Regex>
+): List<Notification> {
+    val deprecatedProperties = loadDeprecations()
+    val warningsAsErrors = configToValidate
+        .subConfig("config")
+        .valueOrDefault("warningsAsErrors", false)
+
+    val validators: List<ConfigValidator> = listOf(
+        InvalidPropertiesConfigValidator(baseline, deprecatedProperties.keys, excludePatterns),
+        DeprecatedPropertiesConfigValidator(deprecatedProperties),
+        MissingRulesConfigValidator(baseline, excludePatterns)
+    )
+
+    return validators
+        .flatMap { it.validate(configToValidate) }
+        .map { notification ->
+            notification.transformIf(warningsAsErrors && notification.level == Level.Warning) {
+                SimpleNotification(
+                    message = notification.message,
+                    level = Level.Error
+                )
+            }
+        }
+}
+
+private fun <T> T.transformIf(condition: Boolean, transform: () -> T): T =
+    if (condition) transform() else this
+
+internal fun Notification.renderMessage(): String =
+    when (level) {
+        Level.Error -> message.red()
+        Level.Warning -> message.yellow()
+        Level.Info -> message
+    }

detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultPropertiesConfigValidator.kt → detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultPropertiesConfigValidator.kt

@@ -1,4 +1,4 @@
-package io.gitlab.arturbosch.detekt.core.config
+package io.gitlab.arturbosch.detekt.core.config.validation
 
 import io.gitlab.arturbosch.detekt.api.Config
 import io.gitlab.arturbosch.detekt.api.ConfigValidator
@@ -8,7 +8,7 @@ import io.gitlab.arturbosch.detekt.api.internal.DefaultRuleSetProvider
 import io.gitlab.arturbosch.detekt.core.ProcessingSettings
 import io.gitlab.arturbosch.detekt.core.rules.RuleSetLocator
 
-class DefaultPropertiesConfigValidator(
+internal class DefaultPropertiesConfigValidator(
     private val settings: ProcessingSettings,
     private val baseline: Config,
 ) : ConfigValidator {