Support altering Constraint path and adding userContext (#167)

README.md

@@ -117,14 +117,39 @@ val validateUser = Validation<UserProfile> {
 }
 ```
 
+#### Custom context
+
+You can add customs context to validation errors
+
+```kotlin
+val validateUser = Validation<UserProfile> {
+    UserProfile::age {
+        minimum(0) userContext Severity.ERROR
+        // You can also set multiple things at once
+        minimum(0).replace(
+            hint = "Registering before birth is not supported",
+            userContext = Severity.ERROR,
+        )
+    }
+}
+```
+
 #### Custom validations
 
-You can add custom validations on properties by using `addConstraint`
+You can add custom validations on properties by using `constrain`
 
 ```kotlin
 val validateUser = Validation<UserProfile> {
     UserProfile::fullName {
-        addConstraint("Name cannot contain a tab") { !it.contains("\t") }
+        constrain("Name cannot contain a tab") { !it.contains("\t") }
+        // Set a custom path for the error
+        constrain("Name must have a non-whitespace character", path = ValidationPath.of("trimmedName")) {
+            it.trim().isNotEmpty()
+        }
+        // Set custom context
+        constrain("Must have 5 characters", userContext = Severity.ERROR) {
+            it.size >= 5
+        }
     }
 }
 ```

api/konform.api

@@ -1,9 +1,22 @@
 public final class io/konform/validation/Constraint {
 	public static final field Companion Lio/konform/validation/Constraint$Companion;
 	public static final field VALUE_IN_HINT Ljava/lang/String;
+	public fun <init> (Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Ljava/util/List;Lkotlin/jvm/functions/Function1;)V
+	public synthetic fun <init> (Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Ljava/util/List;Lkotlin/jvm/functions/Function1;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Ljava/lang/String;
+	public final fun component2 ()Lio/konform/validation/path/ValidationPath;
+	public final fun component3 ()Ljava/lang/Object;
+	public final fun component4 ()Ljava/util/List;
+	public final fun component5 ()Lkotlin/jvm/functions/Function1;
+	public final fun copy (Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Ljava/util/List;Lkotlin/jvm/functions/Function1;)Lio/konform/validation/Constraint;
+	public static synthetic fun copy$default (Lio/konform/validation/Constraint;Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Ljava/util/List;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lio/konform/validation/Constraint;
+	public fun equals (Ljava/lang/Object;)Z
 	public final fun getHint ()Ljava/lang/String;
+	public final fun getPath ()Lio/konform/validation/path/ValidationPath;
 	public final fun getTemplateValues ()Ljava/util/List;
 	public final fun getTest ()Lkotlin/jvm/functions/Function1;
+	public final fun getUserContext ()Ljava/lang/Object;
+	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
 }
 
@@ -64,7 +77,10 @@ public final class io/konform/validation/ValidationBuilder {
 	public static final field Companion Lio/konform/validation/ValidationBuilder$Companion;
 	public fun <init> ()V
 	public final fun addConstraint (Ljava/lang/String;[Ljava/lang/String;Lkotlin/jvm/functions/Function1;)Lio/konform/validation/Constraint;
+	public final fun applyConstraint (Lio/konform/validation/Constraint;)Lio/konform/validation/Constraint;
 	public final fun build ()Lio/konform/validation/Validation;
+	public final fun constrain (Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)Lio/konform/validation/Constraint;
+	public static synthetic fun constrain$default (Lio/konform/validation/ValidationBuilder;Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lio/konform/validation/Constraint;
 	public final fun hint (Lio/konform/validation/Constraint;Ljava/lang/String;)Lio/konform/validation/Constraint;
 	public final fun ifPresent (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;)V
 	public final fun ifPresent (Lkotlin/reflect/KFunction;Lkotlin/jvm/functions/Function1;)V
@@ -77,10 +93,15 @@ public final class io/konform/validation/ValidationBuilder {
 	public final fun onEachIterable (Lkotlin/reflect/KProperty1;Lkotlin/jvm/functions/Function1;)V
 	public final fun onEachMap (Lkotlin/reflect/KFunction;Lkotlin/jvm/functions/Function1;)V
 	public final fun onEachMap (Lkotlin/reflect/KProperty1;Lkotlin/jvm/functions/Function1;)V
+	public final fun path (Lio/konform/validation/Constraint;Lio/konform/validation/path/ValidationPath;)Lio/konform/validation/Constraint;
+	public final fun replace (Lio/konform/validation/Constraint;Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;)Lio/konform/validation/Constraint;
+	public static synthetic fun replace$default (Lio/konform/validation/ValidationBuilder;Lio/konform/validation/Constraint;Ljava/lang/String;Lio/konform/validation/path/ValidationPath;Ljava/lang/Object;ILjava/lang/Object;)Lio/konform/validation/Constraint;
+	public final fun replaceConstraint (Lio/konform/validation/Constraint;Lio/konform/validation/Constraint;)Lio/konform/validation/Constraint;
 	public final fun required (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;)V
 	public final fun required (Lkotlin/reflect/KFunction;Lkotlin/jvm/functions/Function1;)V
 	public final fun required (Lkotlin/reflect/KProperty1;Lkotlin/jvm/functions/Function1;)V
 	public final fun run (Lio/konform/validation/Validation;)V
+	public final fun userContext (Lio/konform/validation/Constraint;Ljava/lang/Object;)Lio/konform/validation/Constraint;
 	public final fun validate (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;)V
 }
 
@@ -97,15 +118,18 @@ public final class io/konform/validation/ValidationBuilderKt {
 }
 
 public final class io/konform/validation/ValidationError {
-	public fun <init> (Lio/konform/validation/path/ValidationPath;Ljava/lang/String;)V
+	public fun <init> (Lio/konform/validation/path/ValidationPath;Ljava/lang/String;Ljava/lang/Object;)V
+	public synthetic fun <init> (Lio/konform/validation/path/ValidationPath;Ljava/lang/String;Ljava/lang/Object;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Lio/konform/validation/path/ValidationPath;
 	public final fun component2 ()Ljava/lang/String;
-	public final fun copy (Lio/konform/validation/path/ValidationPath;Ljava/lang/String;)Lio/konform/validation/ValidationError;
-	public static synthetic fun copy$default (Lio/konform/validation/ValidationError;Lio/konform/validation/path/ValidationPath;Ljava/lang/String;ILjava/lang/Object;)Lio/konform/validation/ValidationError;
+	public final fun component3 ()Ljava/lang/Object;
+	public final fun copy (Lio/konform/validation/path/ValidationPath;Ljava/lang/String;Ljava/lang/Object;)Lio/konform/validation/ValidationError;
+	public static synthetic fun copy$default (Lio/konform/validation/ValidationError;Lio/konform/validation/path/ValidationPath;Ljava/lang/String;Ljava/lang/Object;ILjava/lang/Object;)Lio/konform/validation/ValidationError;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getDataPath ()Ljava/lang/String;
 	public final fun getMessage ()Ljava/lang/String;
 	public final fun getPath ()Lio/konform/validation/path/ValidationPath;
+	public final fun getUserContext ()Ljava/lang/Object;
 	public fun hashCode ()I
 	public final fun mapPath (Lkotlin/jvm/functions/Function1;)Lio/konform/validation/ValidationError;
 	public fun toString ()Ljava/lang/String;
@@ -311,8 +335,7 @@ public final class io/konform/validation/path/ValidationPath {
 }
 
 public final class io/konform/validation/path/ValidationPath$Companion {
-	public final fun fromAny ([Ljava/lang/Object;)Lio/konform/validation/path/ValidationPath;
-	public final fun of (Lio/konform/validation/path/PathSegment;)Lio/konform/validation/path/ValidationPath;
+	public final fun of ([Ljava/lang/Object;)Lio/konform/validation/path/ValidationPath;
 }
 
 public final class io/konform/validation/types/CallableValidation : io/konform/validation/Validation {
@@ -325,6 +348,19 @@ public final class io/konform/validation/types/CallableValidation : io/konform/v
 	public fun validate (Ljava/lang/Object;)Lio/konform/validation/ValidationResult;
 }
 
+public final class io/konform/validation/types/ConstraintsValidation : io/konform/validation/Validation {
+	public fun <init> (Ljava/util/List;)V
+	public final fun copy (Ljava/util/List;)Lio/konform/validation/types/ConstraintsValidation;
+	public static synthetic fun copy$default (Lio/konform/validation/types/ConstraintsValidation;Ljava/util/List;ILjava/lang/Object;)Lio/konform/validation/types/ConstraintsValidation;
+	public fun equals (Ljava/lang/Object;)Z
+	public fun hashCode ()I
+	public fun invoke (Ljava/lang/Object;)Lio/konform/validation/ValidationResult;
+	public fun prependPath (Lio/konform/validation/path/PathSegment;)Lio/konform/validation/Validation;
+	public fun prependPath (Lio/konform/validation/path/ValidationPath;)Lio/konform/validation/Validation;
+	public fun toString ()Ljava/lang/String;
+	public fun validate (Ljava/lang/Object;)Lio/konform/validation/ValidationResult;
+}
+
 public final class io/konform/validation/types/EmptyValidation : io/konform/validation/Validation {
 	public static final field INSTANCE Lio/konform/validation/types/EmptyValidation;
 	public fun equals (Ljava/lang/Object;)Z

src/commonMain/kotlin/io/konform/validation/Constraint.kt

@@ -1,15 +1,23 @@
 package io.konform.validation
 
+import io.konform.validation.path.ValidationPath
+
 /**
  * @param hint for a failed validation. "{value}" will be replaced by the toString-ed value that is being validated
+ * @param path [ValidationPath] for this constraint, will be reported in [ValidationError]
+ * @param userContext Optional context set by the user to add more information to the validation, e.g. severity
  * @param test the predicate that must be satisfied
+ * @see [ValidationBuilder.hint]
+ * @see [ValidationBuilder.path]
+ * @see [ValidationBuilder.userContext]
  */
-public class Constraint<in R> internal constructor(
+public data class Constraint<in R>(
     public val hint: String,
+    public val path: ValidationPath = ValidationPath.EMPTY,
+    public val userContext: Any? = null,
     @Deprecated("Put template parameters directly into the hint.")
     public val templateValues: List<String> = emptyList(),
     public val test: (R) -> Boolean,
-    // TODO: Add customizable Path parameter settable with a path() method
 ) {
     override fun toString(): String = "Constraint(\"$hint\")"
 

src/commonMain/kotlin/io/konform/validation/ValidationBuilder.kt

@@ -29,24 +29,46 @@ public class ValidationBuilder<T> {
         subValidations
             .let {
                 if (constraints.isNotEmpty()) {
-                    it.prepend(ConstraintsValidation(ValidationPath.EMPTY, constraints))
+                    it.prepend(ConstraintsValidation(constraints))
                 } else {
                     it
                 }
             }.flatten()
 
+    @Deprecated(
+        "Use constrain(), templateValues are no longer supported, put them directly in the hint",
+        ReplaceWith("constrain(errorMessage, test)"),
+    )
     public fun addConstraint(
         errorMessage: String,
         vararg templateValues: String,
         test: (T) -> Boolean,
-    ): Constraint<T> = Constraint(errorMessage, templateValues.toList(), test).also { constraints.add(it) }
+    ): Constraint<T> = applyConstraint(Constraint(errorMessage, templateValues = templateValues.toList(), test = test))
 
-    @Suppress("DEPRECATION")
-    public infix fun Constraint<T>.hint(hint: String): Constraint<T> =
-        Constraint(hint, this.templateValues, this.test).also {
-            constraints.remove(this)
-            constraints.add(it)
-        }
+    /** Add a new [Constraint] to this validation. */
+    public fun constrain(
+        hint: String,
+        path: ValidationPath = ValidationPath.EMPTY,
+        userContext: Any? = null,
+        test: (T) -> Boolean,
+    ): Constraint<T> = applyConstraint(Constraint(hint, path, userContext, emptyList(), test))
+
+    /** Replace one or more properties of a [Constraint]. */
+    public fun Constraint<T>.replace(
+        hint: String = this.hint,
+        path: ValidationPath = this.path,
+        userContext: Any? = this.userContext,
+    ): Constraint<T> = replaceConstraint(this, this.copy(hint = hint, path = path, userContext = userContext))
+
+    /** Change the hint on a [Constraint]. */
+    public infix fun Constraint<T>.hint(hint: String): Constraint<T> = replaceConstraint(this, this.copy(hint = hint))
+
+    /** Change the path on a [Constraint]. */
+    public infix fun Constraint<T>.path(path: ValidationPath): Constraint<T> = replaceConstraint(this, this.copy(path = path))
+
+    /** Change the userContext on a [Constraint]. */
+    public infix fun Constraint<T>.userContext(userContext: Any?): Constraint<T> =
+        replaceConstraint(this, this.copy(userContext = userContext))
 
     private fun <R> onEachIterable(
         pathSegment: PathSegment,
@@ -90,7 +112,7 @@ public class ValidationBuilder<T> {
     public infix fun <K, V> KFunction1<T, Map<K, V>>.onEach(init: ValidationBuilder<Map.Entry<K, V>>.() -> Unit): Unit =
         onEachMap(FuncRef(this), this, init)
 
-    public operator fun <R> KProperty1<T, R>.invoke(init: ValidationBuilder<R>.() -> Unit): Unit = validate(PropRef(this), this, init)
+    public operator fun <R> KProperty1<T, R>.invoke(init: ValidationBuilder<R>.() -> Unit): Unit = validate(this, this, init)
 
     public operator fun <R> KFunction1<T, R>.invoke(init: ValidationBuilder<R>.() -> Unit): Unit = validate(this, this, init)
 
@@ -136,6 +158,24 @@ public class ValidationBuilder<T> {
         subValidations.add(validation)
     }
 
+    /** Add a [Constraint] and return it. */
+    public fun applyConstraint(constraint: Constraint<T>): Constraint<T> {
+        constraints.add(constraint)
+        return constraint
+    }
+
+    /** Replace a [Constraint] and return the replacement */
+    public fun replaceConstraint(
+        old: Constraint<T>,
+        replacement: Constraint<T>,
+    ): Constraint<T> {
+        // It's very likely that the last added constraint is the one to be replaced so optimize for that
+        val idx = if (constraints.lastOrNull() === old) constraints.size - 1 else constraints.indexOf(old)
+        if (idx == -1) throw IllegalArgumentException("Not found in existing constraints: $old")
+        constraints[idx] = replacement
+        return replacement
+    }
+
     public inline fun <reified SubT : T & Any> ifInstanceOf(init: ValidationBuilder<SubT>.() -> Unit): Unit =
         run(IsClassValidation<SubT, T>(SubT::class, required = false, buildWithNew(init)))
 

src/commonMain/kotlin/io/konform/validation/ValidationError.kt

@@ -8,6 +8,7 @@ import io.konform.validation.path.ValidationPath
 public data class ValidationError(
     public val path: ValidationPath,
     public val message: String,
+    public val userContext: Any? = null,
 ) {
     public val dataPath: String get() = path.dataPath
 
@@ -19,24 +20,21 @@ public data class ValidationError(
 
     internal companion object {
         internal fun of(
-            pathSegment: PathSegment,
+            pathSegment: Any,
             message: String,
         ): ValidationError = ValidationError(ValidationPath.of(pathSegment), message)
 
-        internal fun ofAny(
-            pathSegment: Any,
-            message: String,
-        ): ValidationError = of(PathSegment.toPathSegment(pathSegment), message)
+        internal fun ofEmptyPath(message: String): ValidationError = ValidationError(ValidationPath.EMPTY, message)
     }
 }
 
 public fun List<ValidationError>.filterPath(vararg validationPath: Any): List<ValidationError> {
-    val path = ValidationPath.fromAny(*validationPath)
+    val path = ValidationPath.of(*validationPath)
     return filter { it.path == path }
 }
 
 public fun List<ValidationError>.filterDataPath(vararg validationPath: Any): List<ValidationError> {
-    val dataPath = ValidationPath.fromAny(*validationPath).dataPath
+    val dataPath = ValidationPath.of(*validationPath).dataPath
     return filter { it.dataPath == dataPath }
 }
 

src/commonMain/kotlin/io/konform/validation/path/ValidationPath.kt

@@ -28,9 +28,6 @@ public data class ValidationPath(
     public companion object {
         internal val EMPTY = ValidationPath(emptyList())
 
-        public fun of(pathSegment: PathSegment): ValidationPath = ValidationPath(listOf(pathSegment))
-
-        public fun fromAny(vararg validationPath: Any): ValidationPath =
-            ValidationPath(validationPath.map { PathSegment.toPathSegment(it) })
+        public fun of(vararg validationPath: Any): ValidationPath = ValidationPath(validationPath.map { PathSegment.toPathSegment(it) })
     }
 }

src/commonMain/kotlin/io/konform/validation/types/ConstraintsValidation.kt

@@ -6,23 +6,19 @@ import io.konform.validation.Valid
 import io.konform.validation.Validation
 import io.konform.validation.ValidationError
 import io.konform.validation.ValidationResult
-import io.konform.validation.path.ValidationPath
 
-internal class ConstraintsValidation<T>(
-    private val path: ValidationPath = ValidationPath.EMPTY,
+public data class ConstraintsValidation<T>(
     private val constraints: List<Constraint<T>>,
 ) : Validation<T> {
     override fun validate(value: T): ValidationResult<T> =
         constraints
             .filterNot { it.test(value) }
-            .map { ValidationError(path, it.createHint(value)) }
+            .map { ValidationError(it.path, it.createHint(value), userContext = it.userContext) }
             .let { errors ->
                 if (errors.isEmpty()) {
                     Valid(value)
                 } else {
                     Invalid(errors)
                 }
             }
-
-    override fun toString(): String = "ConstraintsValidation(path=$path,constraints=$constraints)"
 }