From 8aee5396871693d2a3ac9665c9ded8fdb2d1350c Mon Sep 17 00:00:00 2001
From: Sha Sha Chu <shasha@pinterest.com>
Date: Fri, 5 Jul 2019 09:18:48 -0700
Subject: [PATCH] Fixing bug with extra indentation after lambda arrow (#508)

* Fixing bug with extra indentation after lambda arrow

Fixes https://github.com/pinterest/ktlint/issues/479

* Adding tests
---
 .../ruleset/experimental/IndentationRule.kt   | 13 ++++++-----
 .../experimental/IndentationRuleTest.kt       | 22 +++++++++++++++++++
 .../spec/indent/format-arrow-expected.kt.spec |  5 +++++
 .../spec/indent/format-arrow.kt.spec          |  5 +++++
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/ktlint-ruleset-experimental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRule.kt b/ktlint-ruleset-experimental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRule.kt
index f102aebc04..e8be27ee42 100644
--- a/ktlint-ruleset-experimental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRule.kt
+++ b/ktlint-ruleset-experimental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRule.kt
@@ -707,11 +707,14 @@ class IndentationRule : Rule("indent"), Rule.Modifier.RestrictToRootLast {
     }
 
     private fun adjustExpectedIndentAfterArrow(n: ASTNode, ctx: IndentContext) {
-        val prevBlockLine = ctx.blockOpeningLineStack.peek() ?: -1
-        if (prevBlockLine != line) {
-            expectedIndent++
-            debug { "++after(ARROW) -> $expectedIndent" }
-            ctx.exitAdjBy(n.treeParent, -1)
+        // Only adjust indents for arrows inside of when statements. Lambda arrows should not increase indent.
+        if (n.treeParent?.elementType == WHEN_ENTRY) {
+            val prevBlockLine = ctx.blockOpeningLineStack.peek() ?: -1
+            if (prevBlockLine != line) {
+                expectedIndent++
+                debug { "++after(ARROW) -> $expectedIndent" }
+                ctx.exitAdjBy(n.treeParent, -1)
+            }
         }
     }
 
diff --git a/ktlint-ruleset-experimental/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRuleTest.kt b/ktlint-ruleset-experimental/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRuleTest.kt
index c32633d845..0f5fbb337f 100644
--- a/ktlint-ruleset-experimental/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRuleTest.kt
+++ b/ktlint-ruleset-experimental/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/IndentationRuleTest.kt
@@ -322,4 +322,26 @@ class IndentationRuleTest {
             )
         ).isEmpty()
     }
+
+    @Test
+    fun `no indentation after lambda arrow`() {
+        assertThat(
+            IndentationRule().lint(
+                """
+                fun bar() {
+                    foo.func {
+                        param1, param2 ->
+                            doSomething()
+                            doSomething2()
+                    }
+                }
+                """.trimIndent()
+            )
+        ).isEqualTo(
+            listOf(
+                LintError(line = 4, col = 1, ruleId = "indent", detail = "Unexpected indentation (12) (should be 8)"),
+                LintError(line = 5, col = 1, ruleId = "indent", detail = "Unexpected indentation (12) (should be 8)")
+            )
+        )
+    }
 }
diff --git a/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow-expected.kt.spec b/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow-expected.kt.spec
index da983689d2..a3ba11cc63 100644
--- a/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow-expected.kt.spec
+++ b/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow-expected.kt.spec
@@ -23,4 +23,9 @@ fun main() {
         2 // second element
         -> true
     }
+    foo.func {
+        param1, param2 ->
+        doSomething()
+        doSomething2()
+    }
 }
diff --git a/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow.kt.spec b/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow.kt.spec
index 5067a8b09a..ac87b97fc2 100644
--- a/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow.kt.spec
+++ b/ktlint-ruleset-experimental/src/test/resources/spec/indent/format-arrow.kt.spec
@@ -20,4 +20,9 @@ fun main() {
         2 // second element
         -> true
     }
+    foo.func {
+        param1, param2 ->
+            doSomething()
+            doSomething2()
+        }
 }