Retry tests in CI (#7106)

buildSrc/build.gradle.kts

@@ -56,6 +56,7 @@ dependencies {
   implementation("com.diffplug.spotless:spotless-plugin-gradle:7.0.2")
   // Needed for japicmp but not automatically brought in for some reason.
   implementation("com.google.guava:guava:33.4.0-jre")
+  implementation("com.gradle.develocity:com.gradle.develocity.gradle.plugin:3.19.1")
   implementation("com.squareup:javapoet:1.13.0")
   implementation("com.squareup.wire:wire-compiler")
   implementation("com.squareup.wire:wire-gradle-plugin")

buildSrc/src/main/kotlin/otel.java-conventions.gradle.kts

@@ -113,6 +113,14 @@ tasks {
       )
     }
 
+    val defaultMaxRetries = if (System.getenv().containsKey("CI")) 2 else 0
+    val maxTestRetries = gradle.startParameter.projectProperties["maxTestRetries"]?.toInt() ?: defaultMaxRetries
+
+    develocity.testRetry {
+      // You can see tests that were retried by this mechanism in the collected test reports and build scans.
+      maxRetries.set(maxTestRetries);
+    }
+
     testLogging {
       exceptionFormat = TestExceptionFormat.FULL
       showExceptions = true