From 07d2ac0e51df170b34cd32e91a5e13a3ed4c66d6 Mon Sep 17 00:00:00 2001
From: Omer Strulovich <ostrulovich@fb.com>
Date: Fri, 8 Apr 2022 19:42:09 -0700
Subject: [PATCH] Improve handling of `as` and `is` when left hand is a
 call-chain

Summary:
This improves the formatting of casting using the `as` keyword.
I am not merging this into the handling of qualified expressions since `as` can only appear in the end of a chain (parenthesis are required to continue the chain in every reasonable case, an unreasonable case is `any as Foo as Bar`, which we can easily support, but why spend time on it)

Reviewed By: hick209

Differential Revision: D35503254

fbshipit-source-id: 0bbc1834bccf4842cf9d97d07750b9939720fc22
---
 .../ktfmt/format/KotlinInputAstVisitor.kt     | 36 ++++++++++---------
 .../facebook/ktfmt/format/FormatterTest.kt    | 22 ++++++++----
 .../format/GoogleStyleFormatterKtTest.kt      | 20 ++++++++---
 3 files changed, 52 insertions(+), 26 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
index 76a930f7..b8181455 100644
--- a/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
+++ b/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
@@ -2068,26 +2068,30 @@ class KotlinInputAstVisitor(
 
   /** Example `a is Int` or `b !is Int` */
   override fun visitIsExpression(expression: KtIsExpression) {
-    builder.block(ZERO) {
-      builder.sync(expression)
-      visit(expression.leftHandSide)
-      builder.space()
-      visit(expression.operationReference)
-      builder.breakOp(Doc.FillMode.INDEPENDENT, " ", expressionBreakIndent)
-      builder.block(expressionBreakIndent) { visit(expression.typeReference) }
-    }
+    builder.sync(expression)
+    val openGroupBeforeLeft = expression.leftHandSide !is KtQualifiedExpression
+    if (openGroupBeforeLeft) builder.open(ZERO)
+    visit(expression.leftHandSide)
+    if (!openGroupBeforeLeft) builder.open(ZERO)
+    builder.breakOp(Doc.FillMode.UNIFIED, " ", expressionBreakIndent)
+    visit(expression.operationReference)
+    builder.breakOp(Doc.FillMode.INDEPENDENT, " ", expressionBreakIndent)
+    builder.block(expressionBreakIndent) { visit(expression.typeReference) }
+    builder.close()
   }
 
   /** Example `a as Int` or `a as? Int` */
   override fun visitBinaryWithTypeRHSExpression(expression: KtBinaryExpressionWithTypeRHS) {
-    builder.block(ZERO) {
-      builder.sync(expression)
-      visit(expression.left)
-      builder.space()
-      visit(expression.operationReference)
-      builder.breakOp(Doc.FillMode.INDEPENDENT, " ", expressionBreakIndent)
-      builder.block(expressionBreakIndent) { visit(expression.right) }
-    }
+    builder.sync(expression)
+    val openGroupBeforeLeft = expression.left !is KtQualifiedExpression
+    if (openGroupBeforeLeft) builder.open(ZERO)
+    visit(expression.left)
+    if (!openGroupBeforeLeft) builder.open(ZERO)
+    builder.breakOp(Doc.FillMode.UNIFIED, " ", expressionBreakIndent)
+    visit(expression.operationReference)
+    builder.breakOp(Doc.FillMode.INDEPENDENT, " ", expressionBreakIndent)
+    builder.block(expressionBreakIndent) { visit(expression.right) }
+    builder.close()
   }
 
   /**
diff --git a/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt b/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt
index 7b591942..ac893e3a 100644
--- a/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/format/FormatterTest.kt
@@ -2122,8 +2122,8 @@ class FormatterTest {
       |      .boom()[1, 3, 5]
       |      .lah
       |      .doo { it }
-      |      .feep[1] as
-      |      Boo
+      |      .feep[1]
+      |      as Boo
       |}
       |""".trimMargin(),
           deduceMaxWidth = true)
@@ -3122,19 +3122,29 @@ class FormatterTest {
       |fun castIt(
       |    something: Any
       |) {
+      |  doIt(
+      |      something
+      |          as List<*>)
+      |  doIt(
+      |      something
+      |          is List<*>)
       |  println(
-      |      something is
+      |      something
+      |          is
       |          List<String>)
       |  doIt(
-      |      something as
+      |      something
+      |          as
       |          List<String>)
       |  println(
-      |      something is
+      |      something
+      |          is
       |          PairList<
       |              String,
       |              Int>)
       |  doIt(
-      |      something as
+      |      something
+      |          as
       |          PairList<
       |              String,
       |              Int>)
diff --git a/core/src/test/java/com/facebook/ktfmt/format/GoogleStyleFormatterKtTest.kt b/core/src/test/java/com/facebook/ktfmt/format/GoogleStyleFormatterKtTest.kt
index d80d1315..caec529b 100644
--- a/core/src/test/java/com/facebook/ktfmt/format/GoogleStyleFormatterKtTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/format/GoogleStyleFormatterKtTest.kt
@@ -461,22 +461,34 @@ class GoogleStyleFormatterKtTest {
       |fun castIt(
       |  something: Any
       |) {
+      |  doIt(
+      |    something
+      |      as List<*>
+      |  )
+      |  doIt(
+      |    something
+      |      is List<*>
+      |  )
       |  println(
-      |    something is
+      |    something
+      |      is
       |      List<String>
       |  )
       |  doIt(
-      |    something as
+      |    something
+      |      as
       |      List<String>
       |  )
       |  println(
-      |    something is
+      |    something
+      |      is
       |      PairList<
       |        String,
       |        Int>
       |  )
       |  doIt(
-      |    something as
+      |    something
+      |      as
       |      PairList<
       |        String,
       |        Int>