From 9545fe93dfe68974ca4bf2f9e6310216fc914e15 Mon Sep 17 00:00:00 2001
From: Jakob Odersky <jakob@odersky.com>
Date: Mon, 21 May 2018 15:05:13 -0700
Subject: Fix camel case subsititution

---
 shared/src/main/scala/caseFormats.scala    | 24 +++++++++++-------------
 shared/src/test/scala/FieldNameTests.scala |  5 +++++
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/shared/src/main/scala/caseFormats.scala b/shared/src/main/scala/caseFormats.scala
index 909e357..f4cc871 100644
--- a/shared/src/main/scala/caseFormats.scala
+++ b/shared/src/main/scala/caseFormats.scala
@@ -15,7 +15,12 @@ trait KebabCase { self: DerivedFormats =>
 object FieldNaming {
 
   @inline final private def isLower(ch: Char): Boolean =
-    ((ch & 0x20) != 0) || (ch == '_')
+    ((ch & 0x20) != 0) && (ch != '_')
+  @inline final private def isUpper(ch: Char): Boolean =
+    ((ch & 0x20) == 0) && (ch != '_')
+
+  @inline final private def toLower(ch: Char): Char =
+    if (ch == '_') '_' else (ch | 0x20).toChar
 
   @inline final def substituteCamel(paramName: String, substitute: Char) = {
     val length = paramName.length
@@ -23,21 +28,14 @@ object FieldNaming {
     var i = 0
     while (i < length) {
       val cur = paramName(i)
-      val lower = isLower(cur)
-      if (lower) {
-        builder.append(cur)
-      } else {
-        builder.append((cur ^ 0x20).toChar)
-      }
-      if (lower && i + 1 < length) {
+      builder.append(toLower(cur))
+      if (isLower(cur) && (i + 1 < length)) {
         val next = paramName(i + 1)
-        if (!isLower(next)) {
+        if (isUpper(next)) {
           builder.append(substitute)
-          builder.append((next ^ 0x20).toChar)
-        } else {
-          builder.append(next)
+          builder.append(toLower(next))
+          i += 1
         }
-        i += 1
       }
       i += 1
     }
diff --git a/shared/src/test/scala/FieldNameTests.scala b/shared/src/test/scala/FieldNameTests.scala
index 885dfb6..ef4064d 100644
--- a/shared/src/test/scala/FieldNameTests.scala
+++ b/shared/src/test/scala/FieldNameTests.scala
@@ -6,9 +6,11 @@ class FieldNameTests extends FlatSpec with FormatTests {
 
   case class A(camelCASE: String, `__a_aB__`: Int, `a-a_B`: Int)
   case class B(camelCaseA: A)
+  case class C(abA: String)
 
   trait All extends DefaultJsonProtocol with DerivedFormats {
     implicit val bFormat = jsonFormat[B]
+    implicit val cFormat = jsonFormat[C]
   }
 
   {
@@ -18,6 +20,9 @@ class FieldNameTests extends FlatSpec with FormatTests {
       B(A("helloWorld", 0, 0)),
       """{"camel_case_a":{"camel_case":"helloWorld","__a_a_b__":0,"a-a_b":0}}"""
     )
+    "abA" should "serialize correctly" in {
+      assert(C("test").toJson === """{"ab_a":"test"}""".parseJson)
+    }
   }
 
   {
-- 
cgit v1.2.3