Preserve new lines between when clauses

Summary: Implemented as requested on #342 Reviewed By: davidtorosyan Differential Revision: D58271914 fbshipit-source-id: 048d9a754b40200f313654775eb743c024073d39
facebook · Jun 7, 2024 · 7d23e59 · 7d23e59
1 parent 8605080
commit 7d23e59
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Showing 2 changed files with 49 additions and 1 deletion.
diff --git a/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt b/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
@@ -1882,8 +1882,12 @@ class KotlinInputAstVisitor(
       builder.space()
       builder.token("{", Doc.Token.RealOrImaginary.REAL, blockIndent, Optional.of(blockIndent))
 
-      expression.entries.forEach { whenEntry ->
+      expression.entries.forEachIndexed { index, whenEntry ->
         builder.block(blockIndent) {
+          if (index != 0) {
+            // preserve new line if there's one
+            builder.blankLineWanted(OpsBuilder.BlankLineWanted.PRESERVE)
+          }
           builder.forcedBreak()
           if (whenEntry.isElse) {
             builder.token("else")

diff --git a/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt b/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt
@@ -1635,6 +1635,50 @@ class FormatterTest {
       |"""
               .trimMargin())
 
+  @Test
+  fun `newlines between clauses of when() are preserved`() {
+    assertThatFormatting(
+            """
+        |fun f(x: Int) {
+        |  when (x) {
+        |
+        |
+        |    1 -> print(1)
+        |    2 -> print(2)
+        |
+        |
+        |    3 ->
+        |        // Comment
+        |        print(3)
+        |
+        |    else -> {
+        |      print("else")
+        |    }
+        |
+        |  }
+        |}
+        |"""
+                .trimMargin())
+        .isEqualTo(
+            """
+        |fun f(x: Int) {
+        |  when (x) {
+        |    1 -> print(1)
+        |    2 -> print(2)
+        |
+        |    3 ->
+        |        // Comment
+        |        print(3)
+        |
+        |    else -> {
+        |      print("else")
+        |    }
+        |  }
+        |}
+        |"""
+                .trimMargin())
+  }
+
   @Test
   fun `when() with a subject expression`() =
       assertFormatted(