Add always ignore differ

.gitignore

@@ -21,5 +21,6 @@ projectFilesBackup/
 version.properties
 RUNNING_PID
 .metals
+metals.sbt
 .bsp
 TempGo.scala

modules/core/src/main/scala/difflicious/AlwaysIgnoreDiffer.scala

@@ -0,0 +1,29 @@
+package difflicious
+
+import difflicious.DiffResult.ValueResult
+
+/** A Differ that always return an Ignored result.
+  * Useful when you can't really diff a type */
+class AlwaysIgnoreDiffer[T] extends Differ[T] {
+  override type R = ValueResult
+
+  override def diff(inputs: DiffInput[T]): ValueResult =
+    ValueResult.Both("[ALWAYS IGNORED]", "[ALWAYS IGNORED]", isSame = true, isIgnored = true)
+
+  override protected def configureIgnored(newIgnored: Boolean): Differ[T] = this
+
+  override protected def configurePath(
+    step: String,
+    nextPath: ConfigurePath,
+    op: ConfigureOp,
+  ): Either[ConfigureError, Differ[T]] = {
+    Left(ConfigureError.PathTooLong(nextPath))
+  }
+
+  override protected def configurePairBy(
+    path: ConfigurePath,
+    op: ConfigureOp.PairBy[_],
+  ): Either[ConfigureError, Differ[T]] = {
+    Left(ConfigureError.InvalidConfigureOp(path, op, "AlwaysIgnoreDiffer"))
+  }
+}

modules/core/src/main/scala/difflicious/Differ.scala

@@ -55,6 +55,9 @@ object Differ extends DifferTupleInstances with DifferGen with DifferTimeInstanc
   def useEquals[T](valueToString: T => String): EqualsDiffer[T] =
     new EqualsDiffer[T](isIgnored = false, valueToString = valueToString)
 
+  /** A Differ that always return an Ignored result. Useful when you can't really diff something */
+  def alwaysIgnore[T]: AlwaysIgnoreDiffer[T] = new AlwaysIgnoreDiffer[T]
+
   // TODO: better string diff (edit distance and a description of how to get there?
   //  this can help especially in cases like extra space or special char)
   implicit val stringDiffer: ValueDiffer[String] = useEquals[String](str => s""""$str"""")