build: always prefer slf4j instead of log4j 1.x

Make sure we get slf4j in every test source set and every application by
default. Saves configuration effort when creating a new library that tests
VIATRA or other dependencies that require log4j.

2 files changed, 21 insertions, 0 deletions

diff --git a/buildSrc/src/main/kotlin/refinery-java-application.gradle.kts b/buildSrc/src/main/kotlin/refinery-java-application.gradle.kts
index b3fab1fa..65409acf 100644
--- a/buildSrc/src/main/kotlin/refinery-java-application.gradle.kts
+++ b/buildSrc/src/main/kotlin/refinery-java-application.gradle.kts
@@ -1,3 +1,5 @@
+import org.gradle.accessors.dm.LibrariesForLibs
+
 plugins {
         application
         id("com.github.johnrengelman.shadow")
@@ -5,6 +7,18 @@ plugins {
 
 apply(plugin = "refinery-java-conventions")
 
+// Use log4j-over-slf4j instead of log4j 1.x when running the application.
+configurations.named("runtimeClasspath") {
+        exclude(group = "log4j", module = "log4j")
+}
+
+val libs = the<LibrariesForLibs>()
+
+dependencies {
+        implementation(libs.slf4j.simple)
+        implementation(libs.slf4j.log4j)
+}
+
 for (taskName in listOf("distTar", "distZip", "shadowDistTar", "shadowDistZip")) {
         tasks.named(taskName) {
                 enabled = false
diff --git a/buildSrc/src/main/kotlin/refinery-java-conventions.gradle.kts b/buildSrc/src/main/kotlin/refinery-java-conventions.gradle.kts
index 2d5ce8b5..3f9b4208 100644
--- a/buildSrc/src/main/kotlin/refinery-java-conventions.gradle.kts
+++ b/buildSrc/src/main/kotlin/refinery-java-conventions.gradle.kts
@@ -17,6 +17,11 @@ repositories {
         }
 }
 
+// Use log4j-over-slf4j instead of log4j 1.x in the tests.
+configurations.testRuntimeClasspath {
+        exclude(group = "log4j", module = "log4j")
+}
+
 val libs = the<LibrariesForLibs>()
 
 dependencies {
@@ -28,6 +33,8 @@ dependencies {
         testImplementation(libs.junit.params)
         testImplementation(libs.mockito.core)
         testImplementation(libs.mockito.junit)
+        testImplementation(libs.slf4j.simple)
+        testImplementation(libs.slf4j.log4j)
 }
 
 java.toolchain {