From 2e7fb81a739e52ec26ba6ea712172888425b8921 Mon Sep 17 00:00:00 2001
From: Tomasz Godzik <tgodzik@virtuslab.com>
Date: Tue, 21 Oct 2025 12:03:46 +0200
Subject: [PATCH] improvement: Add fallback to 2.3.0 for older Scala versions

---
 .../scala/scoverage/ScoverageSbtPlugin.scala  | 13 ++++++++++++-
 .../scoverage/good-coverage-older/build.sbt   | 17 +++++++++++++++++
 .../good-coverage-older/project/plugins.sbt   |  9 +++++++++
 .../src/main/scala/GoodCoverage.scala         |  7 +++++++
 .../src/main/scala/two/GoodCoverage.scala     |  9 +++++++++
 .../src/test/scala/GoodCoverageSpec.scala     | 19 +++++++++++++++++++
 .../scoverage/good-coverage-older/test        |  5 +++++
 7 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/build.sbt
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/project/plugins.sbt
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/src/main/scala/GoodCoverage.scala
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/src/main/scala/two/GoodCoverage.scala
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/src/test/scala/GoodCoverageSpec.scala
 create mode 100644 src/sbt-test/scoverage/good-coverage-older/test

diff --git a/src/main/scala/scoverage/ScoverageSbtPlugin.scala b/src/main/scala/scoverage/ScoverageSbtPlugin.scala
index c376fcae..76a9cdf3 100644
--- a/src/main/scala/scoverage/ScoverageSbtPlugin.scala
+++ b/src/main/scala/scoverage/ScoverageSbtPlugin.scala
@@ -70,7 +70,18 @@ object ScoverageSbtPlugin extends AutoPlugin {
     coverageReport := coverageReport0.value,
     coverageAggregate := coverageAggregate0.value,
     coverageAggregate / aggregate := false,
-    coverageDataDir := crossTarget.value
+    coverageDataDir := crossTarget.value,
+    coverageScalacPluginVersion := {
+      scalaVersion.value match {
+        case "2.13.11" => "2.3.0"
+        case "2.13.12" => "2.3.0"
+        case "2.13.13" => "2.3.0"
+        case "2.13.14" => "2.3.0"
+        case "2.13.15" => "2.3.0"
+        case "2.12.16" => "2.3.0"
+        case _         => defaultScoverageVersion
+      }
+    }
   ) ++ coverageSettings ++ scalacSettings
 
   private def isScala2(scalaVersion: String) =
diff --git a/src/sbt-test/scoverage/good-coverage-older/build.sbt b/src/sbt-test/scoverage/good-coverage-older/build.sbt
new file mode 100644
index 00000000..aa52d462
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/build.sbt
@@ -0,0 +1,17 @@
+version := "0.1"
+
+// Set older version to make sure fallbacks work correctly
+scalaVersion := "2.13.11"
+
+libraryDependencies += "org.scalameta" %% "munit" % "1.0.0-M10" % Test
+
+coverageMinimumStmtTotal := 100
+coverageMinimumBranchTotal := 100
+coverageMinimumStmtPerPackage := 100
+coverageMinimumBranchPerPackage := 100
+coverageMinimumStmtPerFile := 100
+coverageMinimumBranchPerFile := 100
+
+coverageFailOnMinimum := true
+
+allowUnsafeScalaLibUpgrade := true
\ No newline at end of file
diff --git a/src/sbt-test/scoverage/good-coverage-older/project/plugins.sbt b/src/sbt-test/scoverage/good-coverage-older/project/plugins.sbt
new file mode 100644
index 00000000..4361ea41
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/project/plugins.sbt
@@ -0,0 +1,9 @@
+val pluginVersion = sys.props.getOrElse(
+  "plugin.version",
+  throw new RuntimeException(
+    """|The system property 'plugin.version' is not defined.
+       |Specify this property using the scriptedLaunchOpts -D.""".stripMargin
+  )
+)
+
+addSbtPlugin("org.scoverage" % "sbt-scoverage" % pluginVersion)
diff --git a/src/sbt-test/scoverage/good-coverage-older/src/main/scala/GoodCoverage.scala b/src/sbt-test/scoverage/good-coverage-older/src/main/scala/GoodCoverage.scala
new file mode 100644
index 00000000..ac6582bb
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/src/main/scala/GoodCoverage.scala
@@ -0,0 +1,7 @@
+object GoodCoverage {
+
+  def sum(num1: Int, num2: Int) = {
+    if (0 == num1) num2 else if (0 == num2) num1 else num1 + num2
+  }
+
+}
diff --git a/src/sbt-test/scoverage/good-coverage-older/src/main/scala/two/GoodCoverage.scala b/src/sbt-test/scoverage/good-coverage-older/src/main/scala/two/GoodCoverage.scala
new file mode 100644
index 00000000..587e11e1
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/src/main/scala/two/GoodCoverage.scala
@@ -0,0 +1,9 @@
+package two
+
+object GoodCoverage {
+
+  def sum(num1: Int, num2: Int) = {
+    if (0 == num1) num2 else if (0 == num2) num1 else num1 + num2
+  }
+
+}
diff --git a/src/sbt-test/scoverage/good-coverage-older/src/test/scala/GoodCoverageSpec.scala b/src/sbt-test/scoverage/good-coverage-older/src/test/scala/GoodCoverageSpec.scala
new file mode 100644
index 00000000..44eec1c9
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/src/test/scala/GoodCoverageSpec.scala
@@ -0,0 +1,19 @@
+import munit.FunSuite
+
+/** Created by tbarke001c on 7/8/14.
+  */
+class GoodCoverageSpec extends FunSuite {
+
+  test("GoodCoverage should sum two numbers") {
+    assertEquals(GoodCoverage.sum(1, 2), 3)
+    assertEquals(GoodCoverage.sum(0, 3), 3)
+    assertEquals(GoodCoverage.sum(3, 0), 3)
+  }
+
+  test("two.GoodCoverage should sum two numbers") {
+    assertEquals(two.GoodCoverage.sum(1, 2), 3)
+    assertEquals(two.GoodCoverage.sum(0, 3), 3)
+    assertEquals(two.GoodCoverage.sum(3, 0), 3)
+  }
+
+}
diff --git a/src/sbt-test/scoverage/good-coverage-older/test b/src/sbt-test/scoverage/good-coverage-older/test
new file mode 100644
index 00000000..c5b157f6
--- /dev/null
+++ b/src/sbt-test/scoverage/good-coverage-older/test
@@ -0,0 +1,5 @@
+# run scoverage
+> clean
+> coverage
+> test
+> coverageReport