Emulate standard interpolator escape treatment

Author: jcracknell

src/main/scala/com/typesafe/scalalogging/LoggerMacro.scala

@@ -239,8 +239,8 @@ private object LoggerMacro {
 
     message.tree match {
       case q"scala.StringContext.apply(..$parts).s(..$args)" =>
-        // Escape slf4j format anchors
-        val messageFormat = parts.map({ case Literal(Constant(s: String)) => s.replace("{}", "\\{}") }).mkString("{}")
+        // Emulate standard interpolator escaping and escape literal slf4j format anchors
+        val messageFormat = parts.map({ case Literal(Constant(s: String)) => StringContext.treatEscapes(s).replace("{}", "\\{}") }).mkString("{}")
         (c.Expr(q"$messageFormat"), args map { arg =>
           // Box interpolated AnyVals by explicitly getting the string representation
           c.Expr[Any](if (arg.tpe <:< weakTypeOf[AnyVal]) q"$arg.toString" else arg)

src/test/scala/com/typesafe/scalalogging/LoggerSpec.scala

@@ -74,6 +74,19 @@ class LoggerSpec extends WordSpec with Matchers with MockitoSugar {
       logger.error(s"foo {} bar $arg1")
       verify(underlying).error("foo \\{} bar {}", arg1)
     }
+
+    "call the underlying logger's error method when the interpolated string contains escape sequences" in {
+      val f = fixture(_.isErrorEnabled, true)
+      import f._
+      logger.error(s"foo\nbar $arg1")
+      verify(underlying).error(s"foo\nbar {}", arg1)
+    }
+    "call the underlying logger's error method when the interpolated string is triple quoted and contains escape sequences" in {
+      val f = fixture(_.isErrorEnabled, true)
+      import f._
+      logger.error(s"""foo\nbar $arg1""")
+      verify(underlying).error(s"""foo\nbar {}""", arg1)
+    }
   }
 
   "Calling error with a message and cause" should {