diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/AllRulesConfig.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/AllRulesConfig.kt
index 26d8e5e88a7..9522973cd8d 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/AllRulesConfig.kt
+++ b/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(
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/CompositeConfig.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/CompositeConfig.kt
index 90aeca227a7..9e7075d85e7 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/CompositeConfig.kt
+++ b/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.
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ConfigValidators.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ConfigValidators.kt
deleted file mode 100644
index bd00be46dc2..00000000000
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ConfigValidators.kt
+++ /dev/null
@@ -1,39 +0,0 @@
-package io.gitlab.arturbosch.detekt.core.config
-
-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.core.NL
-import io.gitlab.arturbosch.detekt.core.ProcessingSettings
-import io.gitlab.arturbosch.detekt.core.extensions.loadExtensions
-import io.gitlab.arturbosch.detekt.core.reporting.red
-import io.gitlab.arturbosch.detekt.core.reporting.yellow
-
-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 Notification.renderMessage(): String =
-    when (level) {
-        Notification.Level.Error -> message.red()
-        Notification.Level.Warning -> message.yellow()
-        Notification.Level.Info -> message
-    }
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DisabledAutoCorrectConfig.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DisabledAutoCorrectConfig.kt
index 193751a0039..6e7bffae848 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DisabledAutoCorrectConfig.kt
+++ b/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 {
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfig.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfig.kt
deleted file mode 100644
index 4f6dfe62d52..00000000000
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfig.kt
+++ /dev/null
@@ -1,153 +0,0 @@
-package io.gitlab.arturbosch.detekt.core.config
-
-import io.github.detekt.utils.openSafeStream
-import io.gitlab.arturbosch.detekt.api.Config
-import io.gitlab.arturbosch.detekt.api.Notification
-import io.gitlab.arturbosch.detekt.api.internal.CommaSeparatedPattern
-import io.gitlab.arturbosch.detekt.api.internal.SimpleNotification
-import java.util.Properties
-
-/**
- * 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.
- */
-val DEFAULT_PROPERTY_EXCLUDES = setOf(
-    ".*>excludes",
-    ".*>includes",
-    ".*>active",
-    ".*>.*>excludes",
-    ".*>.*>includes",
-    ".*>.*>active",
-    ".*>.*>autoCorrect",
-    ".*>severity",
-    ".*>.*>severity",
-    "build>weights.*",
-    ".*>.*>ignoreAnnotated",
-    ".*>.*>ignoreFunction",
-).joinToString(",")
-
-fun validateConfig(
-    config: Config,
-    baseline: Config,
-    excludePatterns: Set<Regex> = CommaSeparatedPattern(DEFAULT_PROPERTY_EXCLUDES).mapToRegex()
-): List<Notification> = validateConfig(
-    config,
-    baseline,
-    ValidationSettings(
-        config.subConfig("config").valueOrDefault("warningsAsErrors", false),
-        excludePatterns,
-    )
-)
-
-internal data class ValidationSettings(
-    val warningsAsErrors: Boolean,
-    val excludePatterns: Set<Regex>,
-)
-
-@Suppress("UNCHECKED_CAST", "ComplexMethod")
-internal fun validateConfig(
-    config: Config,
-    baseline: Config,
-    settings: ValidationSettings,
-): 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 $actualClass"
-    }
-
-    if (config == Config.empty) {
-        return emptyList()
-    }
-
-    val (warningsAsErrors, excludePatterns) = settings
-    val notifications = mutableListOf<Notification>()
-
-    fun getDeprecatedProperties(): List<Pair<Regex, String>> {
-        return settings.javaClass.classLoader
-            .getResource("deprecation.properties")!!
-            .openSafeStream()
-            .use { inputStream ->
-                val prop = Properties().apply { load(inputStream) }
-
-                prop.entries.map { entry ->
-                    (entry.key as String).toRegex() to (entry.value as String)
-                }
-            }
-    }
-
-    fun testKeys(current: Map<String, Any>, base: Map<String, Any>, parentPath: String?) {
-        for (prop in current.keys) {
-            val propertyPath = "${if (parentPath == null) "" else "$parentPath>"}$prop"
-
-            val deprecationWarning = getDeprecatedProperties()
-                .find { (regex, _) -> regex.matches(propertyPath) }
-                ?.second
-            val isExcluded = excludePatterns.any { it.matches(propertyPath) }
-
-            if (deprecationWarning != null) {
-                notifications.add(propertyIsDeprecated(propertyPath, deprecationWarning, warningsAsErrors))
-            }
-
-            if (deprecationWarning != null || isExcluded) {
-                continue
-            }
-
-            if (!base.contains(prop)) {
-                notifications.add(propertyDoesNotExists(propertyPath))
-            } else if (current[prop] is String && base[prop] is List<*>) {
-                notifications.add(propertyShouldBeAnArray(propertyPath, warningsAsErrors))
-            }
-
-            val next = current[prop] as? Map<String, Any>
-            val nextBase = base[prop] as? Map<String, Any>
-
-            when {
-                next == null && nextBase != null -> notifications.add(nestedConfigurationExpected(propertyPath))
-                base.contains(prop) && next != null && nextBase == null ->
-                    notifications.add(unexpectedNestedConfiguration(propertyPath))
-                next != null && nextBase != null -> testKeys(next, nextBase, propertyPath)
-            }
-        }
-    }
-
-    when (config) {
-        is YamlConfig -> testKeys(config.properties, baseline.properties, null)
-        is ValidatableConfiguration -> notifications.addAll(config.validate(baseline, excludePatterns))
-        else -> error("Unsupported config type for validation: '${config::class}'.")
-    }
-
-    return notifications
-}
-
-internal fun propertyDoesNotExists(prop: String): Notification =
-    SimpleNotification("Property '$prop' is misspelled or does not exist.")
-
-internal fun nestedConfigurationExpected(prop: String): Notification =
-    SimpleNotification("Nested config expected for '$prop'.")
-
-internal fun unexpectedNestedConfiguration(prop: String): Notification =
-    SimpleNotification("Unexpected nested config for '$prop'.")
-
-internal fun propertyIsDeprecated(
-    prop: String,
-    deprecationDescription: String,
-    reportAsError: Boolean,
-): Notification =
-    SimpleNotification(
-        "Property '$prop' is deprecated. $deprecationDescription.",
-        if (reportAsError) Notification.Level.Error else Notification.Level.Warning,
-    )
-
-internal fun propertyShouldBeAnArray(
-    prop: String,
-    reportAsError: Boolean,
-): Notification =
-    SimpleNotification(
-        "Property '$prop' should be a YAML array instead of a comma-separated String.",
-        if (reportAsError) Notification.Level.Error else Notification.Level.Warning,
-    )
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/YamlConfig.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/YamlConfig.kt
index 24c9d5cd25e..b0ae1d6481d 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/YamlConfig.kt
+++ b/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
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidator.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidator.kt
new file mode 100644
index 00000000000..9bb1270cf09
--- /dev/null
+++ b/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>
+}
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ConfigValidation.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ConfigValidation.kt
new file mode 100644
index 00000000000..3e6051077e3
--- /dev/null
+++ b/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
+    }
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultPropertiesConfigValidator.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultPropertiesConfigValidator.kt
similarity index 91%
rename from detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultPropertiesConfigValidator.kt
rename to detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultPropertiesConfigValidator.kt
index 302b9c18033..7578ad2fa72 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultPropertiesConfigValidator.kt
+++ b/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 {
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidator.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidator.kt
new file mode 100644
index 00000000000..a77d6c8b119
--- /dev/null
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidator.kt
@@ -0,0 +1,44 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.api.internal.SimpleNotification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+
+internal class DeprecatedPropertiesConfigValidator(
+    private val deprecatedProperties: Map<String, String>,
+) : AbstractYamlConfigValidator() {
+    override fun validate(
+        configToValidate: YamlConfig,
+        settings: ValidationSettings
+    ): Collection<Notification> {
+        val configAsMap = configToValidate.properties
+        return deprecatedProperties
+            .map { (path, description) -> path.split(">") to description }
+            .filter { (path, _) -> configAsMap.hasValue(path) }
+            .map { (path, description) -> createNotification(path, description) }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private fun Map<String, Any>.hasValue(propertyPath: List<String>): Boolean {
+        if (propertyPath.isEmpty()) {
+            return false
+        }
+        if (propertyPath.size == 1) {
+            return this.containsKey(propertyPath.first())
+        }
+
+        val subMap = this[propertyPath.first()] as? Map<String, Any> ?: return false
+        return subMap.hasValue(propertyPath.drop(1))
+    }
+
+    private fun createNotification(
+        propertyPath: List<String>,
+        deprecationDescription: String,
+    ): Notification {
+        val prop = propertyPath.joinToString(">")
+        return SimpleNotification(
+            "Property '$prop' is deprecated. $deprecationDescription.",
+            Notification.Level.Warning,
+        )
+    }
+}
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/Deprecations.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/Deprecations.kt
new file mode 100644
index 00000000000..869b745f041
--- /dev/null
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/Deprecations.kt
@@ -0,0 +1,17 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.github.detekt.utils.openSafeStream
+import java.util.Properties
+
+internal fun loadDeprecations(): Map<String, String> {
+    return ValidationSettings::class.java.classLoader
+        .getResource("deprecation.properties")!!
+        .openSafeStream()
+        .use { inputStream ->
+            val prop = Properties().apply { load(inputStream) }
+
+            prop.entries.associate { entry ->
+                (entry.key as String) to (entry.value as String)
+            }
+        }
+}
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidator.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidator.kt
new file mode 100644
index 00000000000..f2c7c68528e
--- /dev/null
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidator.kt
@@ -0,0 +1,89 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.api.internal.SimpleNotification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+
+internal class InvalidPropertiesConfigValidator(
+    private val baseline: YamlConfig,
+    private val deprecatedProperties: Set<String>,
+    private val excludePatterns: Set<Regex>,
+) : AbstractYamlConfigValidator() {
+
+    override fun validate(
+        configToValidate: YamlConfig,
+        settings: ValidationSettings
+    ): Collection<Notification> {
+        return testKeys(configToValidate.properties, baseline.properties)
+    }
+
+    private fun testKeys(
+        configToValidate: Map<String, Any>,
+        baseline: Map<String, Any>,
+        parentPath: String? = null
+    ): List<Notification> {
+        val notifications = mutableListOf<Notification>()
+        for (prop in configToValidate.keys) {
+            val propertyPath = "${if (parentPath == null) "" else "$parentPath>"}$prop"
+            val isExcluded = excludePatterns.any { it.matches(propertyPath) }
+            val isDeprecated = deprecatedProperties.contains(propertyPath)
+            if (isExcluded || isDeprecated) {
+                continue
+            }
+            notifications.addAll(
+                checkProp(
+                    propertyName = prop,
+                    propertyPath = propertyPath,
+                    configToValidate = configToValidate,
+                    baseline = baseline
+                )
+            )
+        }
+        return notifications
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private fun checkProp(
+        propertyName: String,
+        propertyPath: String,
+        configToValidate: Map<String, Any>,
+        baseline: Map<String, Any>
+    ): List<Notification> {
+        if (!baseline.contains(propertyName)) {
+            return listOf(propertyDoesNotExists(propertyPath))
+        }
+        if (configToValidate[propertyName] is String && baseline[propertyName] is List<*>) {
+            return listOf(propertyShouldBeAnArray(propertyPath))
+        }
+
+        val next = configToValidate[propertyName] as? Map<String, Any>
+        val nextBase = baseline[propertyName] as? Map<String, Any>
+        return when {
+            next == null && nextBase != null ->
+                listOf(nestedConfigurationExpected(propertyPath))
+            baseline.contains(propertyName) && next != null && nextBase == null ->
+                listOf(unexpectedNestedConfiguration(propertyPath))
+            next != null && nextBase != null ->
+                testKeys(next, nextBase, propertyPath)
+            else -> emptyList()
+        }
+    }
+
+    companion object {
+
+        internal fun propertyDoesNotExists(prop: String): Notification =
+            SimpleNotification("Property '$prop' is misspelled or does not exist.")
+
+        internal fun nestedConfigurationExpected(prop: String): Notification =
+            SimpleNotification("Nested config expected for '$prop'.")
+
+        internal fun unexpectedNestedConfiguration(prop: String): Notification =
+            SimpleNotification("Unexpected nested config for '$prop'.")
+
+        internal fun propertyShouldBeAnArray(prop: String): Notification =
+            SimpleNotification(
+                "Property '$prop' should be a YAML array instead of a comma-separated String.",
+                Notification.Level.Warning,
+            )
+    }
+}
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidator.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidator.kt
new file mode 100644
index 00000000000..fe22e8ab2ff
--- /dev/null
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidator.kt
@@ -0,0 +1,81 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.api.RuleSetProvider
+import io.gitlab.arturbosch.detekt.api.internal.DefaultRuleSetProvider
+import io.gitlab.arturbosch.detekt.api.internal.SimpleNotification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import java.util.ServiceLoader
+
+internal class MissingRulesConfigValidator(
+    private val baseline: YamlConfig,
+    private val excludePatterns: Set<Regex>,
+) : AbstractYamlConfigValidator() {
+
+    override fun validate(
+        configToValidate: YamlConfig,
+        settings: ValidationSettings
+    ): Collection<Notification> {
+        if (!settings.checkExhaustiveness) {
+            return emptyList()
+        }
+        return defaultRuleSetNames.flatMap { ruleSet -> validateRuleSet(ruleSet, configToValidate) }
+    }
+
+    private fun validateRuleSet(
+        ruleSet: String,
+        configToValidate: YamlConfig,
+    ): List<Notification> {
+        val ruleSetConfigToValidate = configToValidate.getSubMapOrNull(ruleSet)
+        val ruleSetConfigFromBaseline = baseline.getSubMapOrNull(ruleSet)
+        return when {
+            ruleSetConfigFromBaseline == null -> emptyList()
+            ruleSetConfigToValidate == null -> listOf(ruleSetMissing(ruleSet))
+            else -> checkForMissingRules(ruleSet, ruleSetConfigToValidate, ruleSetConfigFromBaseline)
+        }
+    }
+
+    private fun checkForMissingRules(
+        ruleSetName: String,
+        ruleSetConfigToValidate: Map<String, Any>,
+        ruleSetConfigFromBaseline: Map<String, Any>,
+    ): List<Notification> {
+        if (ruleSetConfigToValidate[Config.ACTIVE_KEY] == false) {
+            return emptyList()
+        }
+
+        return ruleSetConfigFromBaseline.keys
+            .filter { ruleNameCandidate -> excludePatterns.none { it.matches("$ruleSetName>$ruleNameCandidate") } }
+            .filter { ruleName -> !ruleSetConfigToValidate.containsKey(ruleName) }
+            .map { ruleName -> ruleMissing(ruleName, ruleSetName) }
+    }
+
+    private fun ruleMissing(ruleName: String, ruleSetName: String): Notification =
+        SimpleNotification(
+            "Rule '$ruleName' from the '$ruleSetName' rule set is missing in the configuration.",
+            Notification.Level.Warning,
+        )
+
+    private fun ruleSetMissing(ruleSetName: String): Notification =
+        SimpleNotification(
+            "Rule set '$ruleSetName' is missing in the configuration.",
+            Notification.Level.Warning,
+        )
+
+    @Suppress("UNCHECKED_CAST")
+    private fun YamlConfig.getSubMapOrNull(propertyName: String) = properties[propertyName] as? Map<String, Any>
+
+    companion object {
+
+        private val defaultRuleSetNames: List<String> by lazy(Companion::loadDefaultRuleSets)
+        private fun loadDefaultRuleSets(): List<String> {
+            return ServiceLoader.load(
+                RuleSetProvider::class.java,
+                MissingRulesConfigValidator::class.java.classLoader
+            )
+                .filterIsInstance<DefaultRuleSetProvider>()
+                .map { it.ruleSetId }
+        }
+    }
+}
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidatableConfiguration.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidatableConfiguration.kt
similarity index 79%
rename from detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidatableConfiguration.kt
rename to detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidatableConfiguration.kt
index 78a97e9dea8..8b69fbfe475 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidatableConfiguration.kt
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidatableConfiguration.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.Notification
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidationSettings.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidationSettings.kt
new file mode 100644
index 00000000000..a1ddf9d4a42
--- /dev/null
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidationSettings.kt
@@ -0,0 +1,5 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+internal data class ValidationSettings(
+    val checkExhaustiveness: Boolean = false,
+)
diff --git a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/tooling/Lifecycle.kt b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/tooling/Lifecycle.kt
index c2070413a3c..5e04be5baac 100644
--- a/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/tooling/Lifecycle.kt
+++ b/detekt-core/src/main/kotlin/io/gitlab/arturbosch/detekt/core/tooling/Lifecycle.kt
@@ -11,7 +11,7 @@ import io.gitlab.arturbosch.detekt.core.Analyzer
 import io.gitlab.arturbosch.detekt.core.DetektResult
 import io.gitlab.arturbosch.detekt.core.FileProcessorLocator
 import io.gitlab.arturbosch.detekt.core.ProcessingSettings
-import io.gitlab.arturbosch.detekt.core.config.checkConfiguration
+import io.gitlab.arturbosch.detekt.core.config.validation.checkConfiguration
 import io.gitlab.arturbosch.detekt.core.extensions.handleReportingExtensions
 import io.gitlab.arturbosch.detekt.core.generateBindingContext
 import io.gitlab.arturbosch.detekt.core.reporting.OutputFacade
diff --git a/detekt-core/src/main/resources/default-detekt-config.yml b/detekt-core/src/main/resources/default-detekt-config.yml
index 59de0ada0e4..219fcc7ad02 100644
--- a/detekt-core/src/main/resources/default-detekt-config.yml
+++ b/detekt-core/src/main/resources/default-detekt-config.yml
@@ -10,6 +10,7 @@ build:
 config:
   validation: true
   warningsAsErrors: false
+  checkExhaustiveness: false
   # when writing own rules with new properties, exclude the property path e.g.: 'my_rule_set,.*>.*>[my_property]'
   excludes: ''
 
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultConfigValidationSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultConfigValidationSpec.kt
deleted file mode 100644
index c18e954802f..00000000000
--- a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/DefaultConfigValidationSpec.kt
+++ /dev/null
@@ -1,20 +0,0 @@
-package io.gitlab.arturbosch.detekt.core.config
-
-import io.gitlab.arturbosch.detekt.test.yamlConfig
-import org.assertj.core.api.Assertions.assertThat
-import org.junit.jupiter.api.Test
-
-class DefaultConfigValidationSpec {
-
-    private val baseline = yamlConfig("default-detekt-config.yml")
-
-    @Test
-    fun `is valid comparing itself`() {
-        assertThat(validateConfig(baseline, baseline)).isEmpty()
-    }
-
-    @Test
-    fun `does not flag common known config sub sections`() {
-        assertThat(validateConfig(yamlConfig("common_known_sections.yml"), baseline)).isEmpty()
-    }
-}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidatorSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidatorSpec.kt
new file mode 100644
index 00000000000..641293a6c69
--- /dev/null
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/AbstractYamlConfigValidatorSpec.kt
@@ -0,0 +1,49 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import io.gitlab.arturbosch.detekt.test.yamlConfigFromContent
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+
+internal class AbstractYamlConfigValidatorSpec {
+
+    @Test
+    fun `use default validation settings`() {
+        val validator = SettingsCapturingValidatorAbstract()
+        val config = yamlConfigFromContent("")
+
+        validator.validate(config)
+
+        assertThat(validator.validationSettings.checkExhaustiveness).isFalse()
+    }
+
+    @ParameterizedTest
+    @ValueSource(booleans = [true, false])
+    fun `extract checkExhaustiveness settings from config`(configValue: Boolean) {
+        val config = yamlConfigFromContent(
+            """
+                config:
+                  checkExhaustiveness: $configValue
+            """.trimIndent()
+        )
+        val validator = SettingsCapturingValidatorAbstract()
+
+        validator.validate(config)
+
+        assertThat(validator.validationSettings.checkExhaustiveness).isEqualTo(configValue)
+    }
+
+    private class SettingsCapturingValidatorAbstract : AbstractYamlConfigValidator() {
+        lateinit var validationSettings: ValidationSettings
+        override fun validate(
+            configToValidate: YamlConfig,
+            settings: ValidationSettings
+        ): Collection<Notification> {
+            validationSettings = settings
+            return emptyList()
+        }
+    }
+}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/CheckConfigurationSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/CheckConfigurationSpec.kt
similarity index 98%
rename from detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/CheckConfigurationSpec.kt
rename to detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/CheckConfigurationSpec.kt
index 9a0d468063c..95e50e18402 100644
--- a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/CheckConfigurationSpec.kt
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/CheckConfigurationSpec.kt
@@ -1,4 +1,4 @@
-package io.gitlab.arturbosch.detekt.core.config
+package io.gitlab.arturbosch.detekt.core.config.validation
 
 import io.github.detekt.test.utils.createTempDirectoryForTest
 import io.github.detekt.tooling.api.InvalidConfig
@@ -15,7 +15,7 @@ import io.gitlab.arturbosch.detekt.test.yamlConfigFromContent
 import org.assertj.core.api.Assertions.assertThatCode
 import org.junit.jupiter.api.Test
 
-class SupportConfigValidationSpec {
+class CheckConfigurationSpec {
 
     private val testDir = createTempDirectoryForTest("detekt-sample")
     private val spec = createNullLoggingSpec {}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultConfigValidationSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultConfigValidationSpec.kt
new file mode 100644
index 00000000000..2a9b3b5f775
--- /dev/null
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DefaultConfigValidationSpec.kt
@@ -0,0 +1,24 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.internal.CommaSeparatedPattern
+import io.gitlab.arturbosch.detekt.test.yamlConfig
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+class DefaultConfigValidationSpec {
+
+    private val baseline = yamlConfig("default-detekt-config.yml")
+    private val defaultExcludePatterns = CommaSeparatedPattern(DEFAULT_PROPERTY_EXCLUDES).mapToRegex()
+
+    @Test
+    fun `is valid comparing itself`() {
+        val actual = validateConfig(baseline, baseline, defaultExcludePatterns)
+        assertThat(actual).isEmpty()
+    }
+
+    @Test
+    fun `does not flag common known config sub sections`() {
+        val actual = validateConfig(yamlConfig("common_known_sections.yml"), baseline, defaultExcludePatterns)
+        assertThat(actual).isEmpty()
+    }
+}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidatorSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidatorSpec.kt
new file mode 100644
index 00000000000..6dd5ff709ff
--- /dev/null
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/DeprecatedPropertiesConfigValidatorSpec.kt
@@ -0,0 +1,36 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import io.gitlab.arturbosch.detekt.test.yamlConfigFromContent
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+internal class DeprecatedPropertiesConfigValidatorSpec {
+    private val deprecatedProperties =
+        mapOf("naming>FunctionParameterNaming>ignoreOverriddenFunctions" to "Use `ignoreOverridden` instead")
+
+    private val subject = DeprecatedPropertiesConfigValidator(deprecatedProperties)
+
+    @Test
+    fun `reports a deprecated property as a warning`() {
+        val settings = ValidationSettings()
+        val config = yamlConfigFromContent(
+            """
+                naming:
+                  FunctionParameterNaming:
+                    ignoreOverriddenFunctions: ''
+            """.trimIndent()
+        ) as YamlConfig
+
+        val result = subject.validate(config, settings)
+
+        assertThat(result).anySatisfy { notification ->
+            assertThat(notification.level)
+                .isEqualTo(Notification.Level.Warning)
+            assertThat(notification.message)
+                .contains("naming>FunctionParameterNaming>ignoreOverriddenFunctions")
+                .contains("Use `ignoreOverridden` instead")
+        }
+    }
+}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfigSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidatorSpec.kt
similarity index 52%
rename from detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfigSpec.kt
rename to detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidatorSpec.kt
index 6d88958c699..93617c8f048 100644
--- a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/ValidateConfigSpec.kt
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/InvalidPropertiesConfigValidatorSpec.kt
@@ -1,53 +1,48 @@
-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.Notification
 import io.gitlab.arturbosch.detekt.api.internal.CommaSeparatedPattern
-import io.gitlab.arturbosch.detekt.test.TestConfig
+import io.gitlab.arturbosch.detekt.core.config.CompositeConfig
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import io.gitlab.arturbosch.detekt.core.config.validation.InvalidPropertiesConfigValidator.Companion.nestedConfigurationExpected
+import io.gitlab.arturbosch.detekt.core.config.validation.InvalidPropertiesConfigValidator.Companion.propertyDoesNotExists
+import io.gitlab.arturbosch.detekt.core.config.validation.InvalidPropertiesConfigValidator.Companion.unexpectedNestedConfiguration
 import io.gitlab.arturbosch.detekt.test.yamlConfig
 import io.gitlab.arturbosch.detekt.test.yamlConfigFromContent
 import org.assertj.core.api.Assertions.assertThat
-import org.assertj.core.api.Assertions.assertThatIllegalArgumentException
-import org.assertj.core.api.Assertions.assertThatIllegalStateException
 import org.junit.jupiter.api.DisplayName
 import org.junit.jupiter.api.Nested
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.params.ParameterizedTest
-import org.junit.jupiter.params.provider.ValueSource
 
-class ValidateConfigSpec {
-
-    private val baseline = yamlConfig("config_validation/baseline.yml")
+internal class InvalidPropertiesConfigValidatorSpec {
+    private val deprecatedProperties = setOf<String>("complexity>LongParameterList>threshold")
+    private val baseline = yamlConfig("config_validation/baseline.yml") as YamlConfig
+    private val defaultExcludePatterns = CommaSeparatedPattern(DEFAULT_PROPERTY_EXCLUDES).mapToRegex()
+    private val subject = InvalidPropertiesConfigValidator(baseline, deprecatedProperties, defaultExcludePatterns)
 
     @Test
     fun `passes for same config test`() {
-        val result = validateConfig(baseline, baseline)
+        val result = subject.validate(baseline)
         assertThat(result).isEmpty()
     }
 
     @Test
     fun `passes for properties which may appear on rules and rule sets but may be not present in default config`() {
-        val result = validateConfig(
-            yamlConfig("config_validation/default-excluded-properties.yml"),
-            baseline
-        )
+        val result = subject.validate(yamlConfig("config_validation/default-excluded-properties.yml"))
         assertThat(result).isEmpty()
     }
 
     @Test
     fun `reports different rule set name`() {
-        val result = validateConfig(
-            yamlConfig("config_validation/other-ruleset-name.yml"),
-            baseline
-        )
+        val result = subject.validate(yamlConfig("config_validation/other-ruleset-name.yml"))
         assertThat(result).contains(propertyDoesNotExists("code-smell"))
     }
 
     @Test
     fun `reports different nested property names`() {
-        val result = validateConfig(
-            yamlConfig("config_validation/other-nested-property-names.yml"),
-            baseline
-        )
+        val result = subject.validate(yamlConfig("config_validation/other-nested-property-names.yml"))
+
         assertThat(result).contains(
             propertyDoesNotExists("complexity>LongLongMethod"),
             propertyDoesNotExists("complexity>LongParameterList>enabled"),
@@ -59,10 +54,7 @@ class ValidateConfigSpec {
 
     @Test
     fun `reports nested configuration expected`() {
-        val result = validateConfig(
-            yamlConfig("config_validation/no-nested-config.yml"),
-            baseline
-        )
+        val result = subject.validate(yamlConfig("config_validation/no-nested-config.yml"))
         assertThat(result).contains(
             nestedConfigurationExpected("complexity"),
             nestedConfigurationExpected("style>WildcardImport")
@@ -71,8 +63,14 @@ class ValidateConfigSpec {
 
     @Test
     fun `reports unexpected nested configs`() {
-        // note that the baseline config is now the first argument
-        val result = validateConfig(baseline, yamlConfig("config_validation/no-value.yml"))
+        // note that the baseline config is now the config to validate
+        val subject =
+            InvalidPropertiesConfigValidator(
+                yamlConfig("config_validation/no-value.yml") as YamlConfig,
+                deprecatedProperties,
+                defaultExcludePatterns
+            )
+        val result = subject.validate(baseline)
         assertThat(result).contains(
             unexpectedNestedConfiguration("style"),
             unexpectedNestedConfiguration("comments")
@@ -80,27 +78,29 @@ class ValidateConfigSpec {
     }
 
     @Test
-    fun `returns an error for an invalid config type`() {
-        val invalidConfig = TestConfig()
-        assertThatIllegalStateException().isThrownBy {
-            validateConfig(invalidConfig, baseline)
-        }.withMessageStartingWith("Unsupported config type for validation")
+    fun `does not report missing property when it is deprecated`() {
+        val result = subject.validate(yamlConfig("config_validation/deprecated-properties.yml"))
+        assertThat(result).isEmpty()
     }
 
     @Test
-    fun `returns an error for an invalid baseline`() {
-        val invalidBaseline = TestConfig()
-        assertThatIllegalArgumentException().isThrownBy {
-            validateConfig(Config.empty, invalidBaseline)
-        }.withMessageStartingWith("Only supported baseline config is the YamlConfig.")
-    }
+    fun `reports a string that should be an array as a warning`() {
+        val config = yamlConfigFromContent(
+            """
+                style:
+                  MagicNumber:
+                    ignoreNumbers: '-1,0,1,2'
+            """.trimIndent()
+        )
 
-    @Test
-    fun `returns an error for an empty baseline`() {
-        val invalidBaseline = Config.empty
-        assertThatIllegalArgumentException().isThrownBy {
-            validateConfig(Config.empty, invalidBaseline)
-        }.withMessageStartingWith("Cannot validate configuration based on an empty baseline config.")
+        val result = subject.validate(config)
+
+        assertThat(result).anySatisfy { notification ->
+            assertThat(notification.message)
+                .contains("style>MagicNumber>ignoreNumbers")
+                .contains("should be a YAML array instead of a comma-separated String")
+            assertThat(notification.level).isEqualTo(Notification.Level.Warning)
+        }
     }
 
     @Nested
@@ -108,25 +108,22 @@ class ValidateConfigSpec {
 
         @Test
         fun `passes for same left, right and baseline config`() {
-            val result = validateConfig(CompositeConfig(baseline, baseline), baseline)
+            val result = CompositeConfig(baseline, baseline).validate(baseline, emptySet())
             assertThat(result).isEmpty()
         }
 
         @Test
         fun `passes for empty configs`() {
-            val result = validateConfig(CompositeConfig(Config.empty, Config.empty), baseline)
+            val result = CompositeConfig(Config.empty, Config.empty).validate(baseline, emptySet())
             assertThat(result).isEmpty()
         }
 
         @Test
         fun `finds accumulated errors`() {
-            val result = validateConfig(
-                CompositeConfig(
-                    yamlConfig("config_validation/other-nested-property-names.yml"),
-                    yamlConfig("config_validation/no-nested-config.yml")
-                ),
-                baseline
-            )
+            val result = CompositeConfig(
+                yamlConfig("config_validation/other-nested-property-names.yml"),
+                yamlConfig("config_validation/no-nested-config.yml")
+            ).validate(baseline, emptySet())
 
             assertThat(result).contains(
                 nestedConfigurationExpected("complexity"),
@@ -147,20 +144,19 @@ class ValidateConfigSpec {
 
         @Test
         fun `does not report any complexity properties`() {
-            val result = validateConfig(
-                yamlConfig("config_validation/other-nested-property-names.yml"),
-                baseline,
-                patterns("complexity")
+            val subject = InvalidPropertiesConfigValidator(baseline, deprecatedProperties, patterns("complexity"))
+
+            val result = subject.validate(
+                yamlConfig("config_validation/other-nested-property-names.yml") as YamlConfig,
             )
             assertThat(result).isEmpty()
         }
 
         @Test
         fun `does not report 'complexity_LargeClass_howMany'`() {
-            val result = validateConfig(
-                yamlConfig("config_validation/other-nested-property-names.yml"),
-                baseline,
-                patterns(".*>.*>howMany")
+            val subject = InvalidPropertiesConfigValidator(baseline, deprecatedProperties, patterns(".*>.*>howMany"))
+            val result = subject.validate(
+                yamlConfig("config_validation/other-nested-property-names.yml") as YamlConfig
             )
 
             assertThat(result).contains(
@@ -178,10 +174,9 @@ class ValidateConfigSpec {
         @Test
         @DisplayName("does not report .*>InnerMap")
         fun `does not report innerMap`() {
-            val result = validateConfig(
-                yamlConfig("config_validation/other-nested-property-names.yml"),
-                baseline,
-                patterns(".*>InnerMap")
+            val subject = InvalidPropertiesConfigValidator(baseline, deprecatedProperties, patterns(".*>InnerMap"))
+            val result = subject.validate(
+                yamlConfig("config_validation/other-nested-property-names.yml") as YamlConfig
             )
 
             assertThat(result).contains(
@@ -196,55 +191,4 @@ class ValidateConfigSpec {
             )
         }
     }
-
-    @Nested
-    inner class `deprecated configuration option` {
-
-        @ParameterizedTest
-        @ValueSource(booleans = [true, false])
-        fun `reports a deprecated property as a warning`(warningsAsErrors: Boolean) {
-            val config = yamlConfigFromContent(
-                """
-                    config:
-                      warningsAsErrors: $warningsAsErrors
-                    naming:
-                      FunctionParameterNaming:
-                        ignoreOverriddenFunctions: ''
-                """.trimIndent()
-            )
-
-            val result = validateConfig(config, config)
-
-            assertThat(result).contains(
-                propertyIsDeprecated(
-                    "naming>FunctionParameterNaming>ignoreOverriddenFunctions",
-                    "Use `ignoreOverridden` instead",
-                    reportAsError = warningsAsErrors
-                )
-            )
-        }
-    }
-
-    @ParameterizedTest
-    @ValueSource(booleans = [true, false])
-    fun `reports a string that should be an array as a warning`(warningsAsErrors: Boolean) {
-        val config = yamlConfigFromContent(
-            """
-                config:
-                  warningsAsErrors: $warningsAsErrors
-                style:
-                  MagicNumber:
-                    ignoreNumbers: '-1,0,1,2'
-            """.trimIndent()
-        )
-
-        val result = validateConfig(config, baseline)
-
-        assertThat(result).contains(
-            propertyShouldBeAnArray(
-                "style>MagicNumber>ignoreNumbers",
-                reportAsError = warningsAsErrors
-            )
-        )
-    }
 }
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidatorSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidatorSpec.kt
new file mode 100644
index 00000000000..9b862d83f92
--- /dev/null
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/MissingRulesConfigValidatorSpec.kt
@@ -0,0 +1,48 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.internal.CommaSeparatedPattern
+import io.gitlab.arturbosch.detekt.core.config.YamlConfig
+import io.gitlab.arturbosch.detekt.test.yamlConfig
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+internal class MissingRulesConfigValidatorSpec {
+    private val baseline = yamlConfig("config_validation/baseline.yml") as YamlConfig
+    private val subject = MissingRulesConfigValidator(
+        baseline,
+        CommaSeparatedPattern(DEFAULT_PROPERTY_EXCLUDES).mapToRegex()
+    )
+
+    @Test
+    fun `do not check for exhaustiveness if disabled by config`() {
+        val config = yamlConfig("config_validation/exhaustiveness-check-disabled.yml")
+
+        val result = subject.validate(config)
+
+        assertThat(result).isEmpty()
+    }
+
+    @Test
+    fun `do not report violations if all rules are mentioned or rule set is disabled`() {
+        val config = yamlConfig("config_validation/exhaustiveness-check-successful.yml")
+
+        val result = subject.validate(config)
+
+        assertThat(result).isEmpty()
+    }
+
+    @Test
+    fun `report violations of missing rules and rule sets`() {
+        val config = yamlConfig("config_validation/exhaustiveness-check-with-error.yml")
+
+        val result = subject.validate(config)
+
+        assertThat(result)
+            .extracting("message")
+            .containsExactlyInAnyOrder(
+                "Rule set 'comments' is missing in the configuration.",
+                "Rule 'LongMethod' from the 'complexity' rule set is missing in the configuration.",
+                "Rule 'WildcardImport' from the 'style' rule set is missing in the configuration.",
+            )
+    }
+}
diff --git a/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidateConfigSpec.kt b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidateConfigSpec.kt
new file mode 100644
index 00000000000..91b4cd7c64c
--- /dev/null
+++ b/detekt-core/src/test/kotlin/io/gitlab/arturbosch/detekt/core/config/validation/ValidateConfigSpec.kt
@@ -0,0 +1,63 @@
+package io.gitlab.arturbosch.detekt.core.config.validation
+
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.Notification
+import io.gitlab.arturbosch.detekt.test.TestConfig
+import io.gitlab.arturbosch.detekt.test.yamlConfig
+import io.gitlab.arturbosch.detekt.test.yamlConfigFromContent
+import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatIllegalArgumentException
+import org.assertj.core.api.Assertions.assertThatIllegalStateException
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+
+internal class ValidateConfigSpec {
+    private val baseline = yamlConfig("config_validation/baseline.yml")
+
+    @Test
+    fun `returns an error for an invalid config type`() {
+        val invalidConfig = TestConfig()
+        assertThatIllegalStateException().isThrownBy {
+            validateConfig(invalidConfig, baseline, emptySet())
+        }.withMessageStartingWith("Unsupported config type for validation")
+    }
+
+    @Test
+    fun `returns an error for an invalid baseline`() {
+        val invalidBaseline = TestConfig()
+        assertThatIllegalArgumentException().isThrownBy {
+            validateConfig(Config.empty, invalidBaseline, emptySet())
+        }.withMessageStartingWith("Only supported baseline config is the YamlConfig.")
+    }
+
+    @Test
+    fun `returns an error for an empty baseline`() {
+        val invalidBaseline = Config.empty
+        assertThatIllegalArgumentException().isThrownBy {
+            validateConfig(Config.empty, invalidBaseline, emptySet())
+        }.withMessageStartingWith("Cannot validate configuration based on an empty baseline config.")
+    }
+
+    @ParameterizedTest
+    @ValueSource(booleans = [true, false])
+    fun `converts warnings to error if config is set up this way`(warningsAsErrors: Boolean) {
+        val config = yamlConfigFromContent(
+            """
+                config:
+                  warningsAsErrors: $warningsAsErrors
+                style:
+                  MagicNumber:
+                    ignoreNumbers: '-1,0,1,2'
+            """.trimIndent()
+        )
+
+        val result = validateConfig(config, baseline, emptySet())
+
+        val expectedLevel = if (warningsAsErrors) Notification.Level.Error else Notification.Level.Warning
+        assertThat(result).anySatisfy { notification ->
+            assertThat(notification.message).contains("style>MagicNumber")
+            assertThat(notification.level).isEqualTo(expectedLevel)
+        }
+    }
+}
diff --git a/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.ConfigValidator b/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.ConfigValidator
index 67f0618954f..4b8243351cd 100644
--- a/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.ConfigValidator
+++ b/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.ConfigValidator
@@ -1 +1 @@
-io.gitlab.arturbosch.detekt.core.config.SampleConfigValidator
+io.gitlab.arturbosch.detekt.core.config.validation.SampleConfigValidator
diff --git a/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider b/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider
index 02f24d5b65e..5767e4ad01f 100644
--- a/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider
+++ b/detekt-core/src/test/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider
@@ -1,3 +1,3 @@
 io.gitlab.arturbosch.detekt.core.TestProvider
 io.gitlab.arturbosch.detekt.core.TestProvider2
-io.gitlab.arturbosch.detekt.core.config.SampleRuleProvider
+io.gitlab.arturbosch.detekt.core.config.validation.SampleRuleProvider
diff --git a/detekt-core/src/test/resources/config_validation/baseline.yml b/detekt-core/src/test/resources/config_validation/baseline.yml
index dc814e5a41a..47e16f0e037 100644
--- a/detekt-core/src/test/resources/config_validation/baseline.yml
+++ b/detekt-core/src/test/resources/config_validation/baseline.yml
@@ -1,5 +1,15 @@
+build:
+  maxIssues: 1
 config:
   warningsAsErrors: true
+  checkExhaustiveness: false
+processors:
+  active: true
+console-reports:
+  active: true
+output-reports:
+  active: true
+
 complexity:
   LongMethod:
     active: true
@@ -17,6 +27,7 @@ complexity:
       active: true
 
 style:
+  active: true
   WildcardImport:
     active: true
   NoElseInWhenExpression:
@@ -26,4 +37,5 @@ style:
     ignoreNumbers: ['-1', '0', '1', '2']
 
 comments:
-  active: false
+  CommentOverPrivateProperty:
+    active: false
diff --git a/detekt-core/src/test/resources/config_validation/deprecated-properties.yml b/detekt-core/src/test/resources/config_validation/deprecated-properties.yml
new file mode 100644
index 00000000000..acd2cfcd348
--- /dev/null
+++ b/detekt-core/src/test/resources/config_validation/deprecated-properties.yml
@@ -0,0 +1,3 @@
+complexity:
+  LongParameterList:
+    threshold: 5
diff --git a/detekt-core/src/test/resources/config_validation/exhaustiveness-check-disabled.yml b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-disabled.yml
new file mode 100644
index 00000000000..cd71203b0a0
--- /dev/null
+++ b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-disabled.yml
@@ -0,0 +1,6 @@
+config:
+  checkExhaustiveness: false
+
+complexity:
+style:
+comments:
diff --git a/detekt-core/src/test/resources/config_validation/exhaustiveness-check-successful.yml b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-successful.yml
new file mode 100644
index 00000000000..bad46ef78fa
--- /dev/null
+++ b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-successful.yml
@@ -0,0 +1,17 @@
+config:
+  checkExhaustiveness: true
+
+complexity:
+  active: false
+
+style:
+  WildcardImport:
+    active: true
+  NoElseInWhenExpression:
+    active: true
+  MagicNumber:
+    active: true
+
+comments:
+  CommentOverPrivateProperty:
+    active: false
diff --git a/detekt-core/src/test/resources/config_validation/exhaustiveness-check-with-error.yml b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-with-error.yml
new file mode 100644
index 00000000000..2088d0ee472
--- /dev/null
+++ b/detekt-core/src/test/resources/config_validation/exhaustiveness-check-with-error.yml
@@ -0,0 +1,21 @@
+config:
+  checkExhaustiveness: true
+
+complexity:
+  LongParameterList:
+    active: false
+  LargeClass:
+    active: false
+  InnerMap:
+    Inner1:
+      active: true
+    Inner2:
+      active: true
+
+style:
+  NoElseInWhenExpression:
+    active: true
+  MagicNumber:
+    active: true
+
+comments:
diff --git a/detekt-generator/src/main/kotlin/io/gitlab/arturbosch/detekt/generator/printer/defaultconfig/ConfigPrinter.kt b/detekt-generator/src/main/kotlin/io/gitlab/arturbosch/detekt/generator/printer/defaultconfig/ConfigPrinter.kt
index 1029d93145d..10bf2f683ac 100644
--- a/detekt-generator/src/main/kotlin/io/gitlab/arturbosch/detekt/generator/printer/defaultconfig/ConfigPrinter.kt
+++ b/detekt-generator/src/main/kotlin/io/gitlab/arturbosch/detekt/generator/printer/defaultconfig/ConfigPrinter.kt
@@ -36,11 +36,12 @@ object ConfigPrinter : DocumentationPrinter<List<RuleSetPage>> {
     """.trimIndent()
 
     private fun defaultConfigConfiguration(): String = """
-        config:
-          validation: true
-          warningsAsErrors: false
-          # when writing own rules with new properties, exclude the property path e.g.: 'my_rule_set,.*>.*>[my_property]'
-          excludes: ''
+      config:
+        validation: true
+        warningsAsErrors: false
+        checkExhaustiveness: false
+        # when writing own rules with new properties, exclude the property path e.g.: 'my_rule_set,.*>.*>[my_property]'
+        excludes: ''
     """.trimIndent()
 
     private fun defaultProcessorsConfiguration(): String = """