From cf340eccc5783bad36a423af3a1608628f3e66bd Mon Sep 17 00:00:00 2001
From: eugene yokota <eed3si9n@gmail.com>
Date: Thu, 24 Sep 2026 16:57:45 -0400
Subject: [PATCH] [2.0.x] Update user-agent to major.minor (#9818)

To avoid user-agent being used for tracking, use only major.minor.
---
 .../CoursierDependencyResolution.scala        |  2 +
 .../scala/sbt/coursierint/LMCoursier.scala    |  6 ++-
 .../scala/sbt/coursierint/UserAgentSpec.scala | 41 +++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 main/src/test/scala/sbt/coursierint/UserAgentSpec.scala

diff --git a/lm-coursier/src/main/scala/lmcoursier/CoursierDependencyResolution.scala b/lm-coursier/src/main/scala/lmcoursier/CoursierDependencyResolution.scala
index df8d22817..d162ca083 100644
--- a/lm-coursier/src/main/scala/lmcoursier/CoursierDependencyResolution.scala
+++ b/lm-coursier/src/main/scala/lmcoursier/CoursierDependencyResolution.scala
@@ -604,6 +604,8 @@ object CoursierDependencyResolution:
             .toOption
             .flatten
         }
+        .flatMap(CrossVersion.partialVersion)
+        .map((major, minor) => s"$major.$minor")
         .getOrElse("2.1")
     s"Coursier/$version (+https://github.com/coursier)"
 
diff --git a/main/src/main/scala/sbt/coursierint/LMCoursier.scala b/main/src/main/scala/sbt/coursierint/LMCoursier.scala
index 947466de2..70233ac7e 100644
--- a/main/src/main/scala/sbt/coursierint/LMCoursier.scala
+++ b/main/src/main/scala/sbt/coursierint/LMCoursier.scala
@@ -38,7 +38,11 @@ object LMCoursier {
   def defaultUserAgent(sbtVer: String): String =
     sys.props.get("sbt.http.agent").getOrElse {
       val cs = CoursierDependencyResolution.coursierUserAgent
-      s"$cs sbt/$sbtVer (+https://www.scala-sbt.org/)".trim
+      val sbtMajorMinor = CrossVersion
+        .partialVersion(sbtVer)
+        .map((major, minor) => s"$major.$minor")
+        .getOrElse(sbtVer)
+      s"$cs sbt/$sbtMajorMinor (+https://www.scala-sbt.org/)".trim
     }
 
   def defaultCacheLocation: File =
diff --git a/main/src/test/scala/sbt/coursierint/UserAgentSpec.scala b/main/src/test/scala/sbt/coursierint/UserAgentSpec.scala
new file mode 100644
index 000000000..85f8c103a
--- /dev/null
+++ b/main/src/test/scala/sbt/coursierint/UserAgentSpec.scala
@@ -0,0 +1,41 @@
+/*
+ * sbt
+ * Copyright 2023, Scala center
+ * Copyright 2011 - 2022, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under Apache License 2.0 (see LICENSE)
+ */
+
+package sbt.coursierint
+
+import hedgehog.*
+import hedgehog.runner.*
+
+object UserAgentSpec extends Properties:
+  private val UserAgent =
+    raw"""Coursier/\d+\.\d+ \(\+https://github\.com/coursier\) sbt/2\.0 \(\+https://www\.scala-sbt\.org/\)""".r
+
+  override def tests: List[Test] =
+    List(
+      property(
+        "defaultUserAgent only includes major.minor of sbt",
+        versionGen.forAll.map { (major, minor, rest) =>
+          val ua = LMCoursier.defaultUserAgent(s"$major.$minor$rest")
+          Result.assert(ua.endsWith(s" sbt/$major.$minor (+https://www.scala-sbt.org/)"))
+        }
+      ),
+      example(
+        "defaultUserAgent only includes major.minor of Coursier",
+        Result.assert(UserAgent.matches(LMCoursier.defaultUserAgent("2.0.0")))
+      ),
+    )
+
+  private def versionGen: Gen[(Int, Int, String)] =
+    for
+      major <- Gen.int(Range.linear(0, 100))
+      minor <- Gen.int(Range.linear(0, 100))
+      patch <- Gen.int(Range.linear(0, 100))
+      suffix <- Gen.element1("", "-M2", "-RC1", "-SNAPSHOT", "-bin-20260924")
+      rest <- Gen.element1("", s".$patch$suffix")
+    yield (major, minor, rest)
+end UserAgentSpec