Move Elvis operator to end of broken lines

This is consistent with other binary operators, and prevents a strange second indent in Elvis chains.
facebook · Aug 24, 2023 · d72a0aa · d72a0aa
1 parent 6384761
commit d72a0aa
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Showing 2 changed files with 65 additions and 16 deletions.
diff --git a/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt b/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
@@ -1199,20 +1199,23 @@ class KotlinInputAstVisitor(
     val leftMostExpression = parts.first()
     visit(leftMostExpression.left)
     for (leftExpression in parts) {
-      when (leftExpression.operationToken) {
-        KtTokens.RANGE -> {}
-        KtTokens.ELVIS -> builder.breakOp(Doc.FillMode.INDEPENDENT, " ", expressionBreakIndent)
-        else -> builder.space()
-      }
-      builder.token(leftExpression.operationReference.text)
       val isFirst = leftExpression === leftMostExpression
-      if (isFirst) {
-        builder.open(expressionBreakIndent)
-      }
+
       when (leftExpression.operationToken) {
-        KtTokens.RANGE -> {}
-        KtTokens.ELVIS -> builder.space()
-        else -> builder.breakOp(Doc.FillMode.UNIFIED, " ", ZERO)
+        KtTokens.RANGE -> {
+          if (isFirst) {
+            builder.open(expressionBreakIndent)
+          }
+          builder.token(leftExpression.operationReference.text)
+        }
+        else -> {
+          builder.space()
+          if (isFirst) {
+            builder.open(expressionBreakIndent)
+          }
+          builder.token(leftExpression.operationReference.text)
+          builder.breakOp(Doc.FillMode.UNIFIED, " ", ZERO)
+        }
       }
       visit(leftExpression.right)
     }

diff --git a/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt b/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt
@@ -2577,8 +2577,8 @@ class FormatterTest {
       |class f {
       |  private val somePropertyWithBackingOne
       |    get() =
-      |        _somePropertyWithBackingOne
-      |            ?: Classname.getStuff<SomePropertyRelatedClassProvider>(requireContext())[
+      |        _somePropertyWithBackingOne ?:
+      |            Classname.getStuff<SomePropertyRelatedClassProvider>(requireContext())[
       |                    somePropertiesProvider, somePropertyCallbacks]
       |                .also { _somePropertyWithBackingOne = it }
       |}
@@ -4250,8 +4250,54 @@ class FormatterTest {
         |  someObject
         |      .someMethodReturningCollection()
         |      .map { it.someProperty }
-        |      .find { it.contains(someSearchValue) }
-        |      ?: someDefaultValue
+        |      .find { it.contains(someSearchValue) } ?:
+        |      someDefaultValue
+        |}
+        |"""
+              .trimMargin(),
+          deduceMaxWidth = true)
+
+  @Test
+  fun `chain of Elvis operator`() =
+      assertFormatted(
+          """
+        |---------------------------
+        |fun f() {
+        |  return option1() ?:
+        |      option2() ?:
+        |      option3() ?:
+        |      option4() ?:
+        |      option5()
+        |}
+        |"""
+              .trimMargin(),
+          deduceMaxWidth = true)
+
+  @Test
+  fun `Elvis operator mixed with plus operator breaking on plus`() =
+      assertFormatted(
+          """
+        |------------------------
+        |fun f() {
+        |  return option1() ?:
+        |      option2() +
+        |          option3() ?:
+        |      option4() +
+        |          option5()
+        |}
+        |"""
+              .trimMargin(),
+          deduceMaxWidth = true)
+
+  @Test
+  fun `Elvis operator mixed with plus operator breaking on elvis`() =
+      assertFormatted(
+          """
+        |---------------------------------
+        |fun f() {
+        |  return option1() ?:
+        |      option2() + option3() ?:
+        |      option4() + option5()
         |}
         |"""
               .trimMargin(),