From f03320047e69f966e328435f48aafeb1c57029cc Mon Sep 17 00:00:00 2001
From: Martin Duhem <mduhem@gradle.com>
Date: Mon, 25 Sep 2023 17:40:12 +0200
Subject: [PATCH 1/2] Keep logger names in hash set

Previously, the list of logger names that have been created in a given
context with Log4J was being kept in a `Vector`. As a result, subsequent
calls to `logger` on a `Log4JLoggerContext` with the same logger name
would introduce duplicates in the list. Note that Log4J's logger
configuration would not allow duplicates, and only one configuration
object for a given logger name will exist. The duplicates in the list of
logger names are therefore unnecessary.

With this patch, the logger names will be kept in a `HashSet`.

Since the logger names are only used to remove the logger configurations
after the logger context is closed, and the logger configurations
contain no duplicates, removing duplicate logger names should not cause
any issue.
---
 .../util-logging/src/main/scala/sbt/util/LoggerContext.scala    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/internal/util-logging/src/main/scala/sbt/util/LoggerContext.scala b/internal/util-logging/src/main/scala/sbt/util/LoggerContext.scala
index c887c786f..58aa5107a 100644
--- a/internal/util-logging/src/main/scala/sbt/util/LoggerContext.scala
+++ b/internal/util-logging/src/main/scala/sbt/util/LoggerContext.scala
@@ -46,7 +46,7 @@ object LoggerContext {
       case a: AbstractConfiguration => a
       case _                        => throw new IllegalStateException("")
     }
-    val loggers = new java.util.Vector[String]
+    val loggers = new java.util.HashSet[String]
     private[this] val closed = new AtomicBoolean(false)
     override def logger(
         name: String,

From d27a1a4ebbb8a52c4800e06dd645ba8dc8d371b5 Mon Sep 17 00:00:00 2001
From: Martin Duhem <mduhem@twitter.com>
Date: Wed, 11 Oct 2023 20:59:19 +0200
Subject: [PATCH 2/2] Add MiMa exclusion

Changing the return type of is fine because this symbol is private and
internal to sbt.
---
 build.sbt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/build.sbt b/build.sbt
index bba828f2a..446206ea1 100644
--- a/build.sbt
+++ b/build.sbt
@@ -428,6 +428,7 @@ lazy val utilLogging = (project in file("internal") / "util-logging")
       exclude[MissingTypesProblem]("sbt.internal.util.ConsoleAppender"),
       exclude[MissingTypesProblem]("sbt.internal.util.BufferedAppender"),
       exclude[MissingClassProblem]("sbt.internal.util.Terminal$BlockingInputStream$"),
+      exclude[IncompatibleResultTypeProblem]("sbt.util.LoggerContext#Log4JLoggerContext.loggers"),
     ),
   )
   .configure(addSbtIO)