From 2d13bda63214922320f2e49ac1c6c703e80a7ea8 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Thu, 19 Sep 2024 09:30:25 -0700
Subject: [PATCH] RedundantBraces: keep unrelated thenp/elsep apart

---
 .../scalafmt/rewrite/RedundantBraces.scala    | 26 ++++++++++++++-
 .../resources/rewrite/RedundantBraces-if.stat | 32 +++++++++----------
 2 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
index c3f2930063..631f7efe77 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
@@ -294,11 +294,12 @@ class RedundantBraces(implicit val ftoks: FormatTokens)
 
   private def onRightBrace(left: Replacement)(implicit
       ft: FormatToken,
+      session: Session,
       style: ScalafmtConfig,
   ): (Replacement, Replacement) = {
     val ok = ft.meta.rightOwner match {
       case _: Term.Block => ftoks.prevNotTrailingComment(ft).isRight &&
-        !braceSeparatesTwoXmlTokens
+        !braceSeparatesTwoXmlTokens && !elseAfterRightBraceThenpOnLeft
       case _ => true
     }
     if (ok) (left, removeToken) else null
@@ -618,4 +619,27 @@ class RedundantBraces(implicit val ftoks: FormatTokens)
   private def braceSeparatesTwoXmlTokens(implicit ft: FormatToken): Boolean = ft
     .left.is[Token.Xml.End] && ftoks.next(ft).right.is[Token.Xml.Start]
 
+  private def elseAfterRightBraceThenpOnLeft(implicit
+      ft: FormatToken,
+      ftoks: FormatTokens,
+      session: Session,
+  ): Boolean = ftoks.nextNonCommentAfter(ft).right.is[Token.KwElse] && {
+    val pft = ftoks.findToken(ft, ftoks.prev) { xft =>
+      xft.left match {
+        case _: Token.Comment => false
+        case _: Token.RightBrace => !session.isRemovedOnLeft(xft, ok = true)
+        case _ => true
+      }
+    }
+    val rbOwner = ft.rightOwner
+    findTreeWithParent(pft.leftOwner) { p =>
+      if (p eq rbOwner) Some(false)
+      else p.parent match {
+        case None => Some(false)
+        case Some(pp: Term.If) if pp.thenp eq p => Some(true)
+        case _ => None
+      }
+    }.isDefined
+  }
+
 }
diff --git a/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces-if.stat b/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces-if.stat
index cb91eeacf5..516a291cdd 100644
--- a/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces-if.stat
+++ b/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces-if.stat
@@ -299,14 +299,14 @@ object a {
     f(imported)
 }
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
-         f(sym)
--      else if (isQualifyingImplicit(name, imported, pre, imported = true))
--        f(imported)
-+  else if (isQualifyingImplicit(name, imported, pre, imported = true))
-+    f(imported)
- }
+object a {
+  if (imported.isOverloaded) {
+    for (sym <- imported.alternatives)
+      if (isQualifyingImplicit(name, sym, pre, imported = true))
+        f(sym)
+  } else if (isQualifyingImplicit(name, imported, pre, imported = true))
+    f(imported)
+}
 <<< #4133 nested braces around expression ending with `if`-without-`else`
 object a {
   if (imported.isOverloaded) {
@@ -320,11 +320,11 @@ object a {
     f(imported)
 }
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
-         f(sym)
--      else if (isQualifyingImplicit(name, imported, pre, imported = true))
--        f(imported)
-+  else if (isQualifyingImplicit(name, imported, pre, imported = true))
-+    f(imported)
- }
+object a {
+  if (imported.isOverloaded) {
+    for (sym <- imported.alternatives)
+      if (isQualifyingImplicit(name, sym, pre, imported = true))
+        f(sym)
+  } else if (isQualifyingImplicit(name, imported, pre, imported = true))
+    f(imported)
+}