automate; read slf4j version from properties instead of hardcoding

Author: ivy-rew

pom.xml

@@ -41,7 +41,6 @@
   <properties>
     <java.version>21</java.version>
     <maven.version>3.9.9</maven.version>
-    <!-- version should match ivy Engine sfl4j version! And version in EngineClassLoaderFactory.SLF4J_VERSION -->
     <slf4j.version>2.0.13</slf4j.version>
     <junit-jupiter.version>5.12.2</junit-jupiter.version>
     <site.path>snapshot</site.path>
@@ -207,6 +206,16 @@
   </dependencies>
 
   <build>
+    <resources>
+      <resource>
+        <directory>src/main/resources</directory>
+      </resource>
+      <resource>
+        <directory>src/main/resources-filtered</directory>
+        <targetPath>ch/ivyteam/ivy/maven/engine</targetPath>
+        <filtering>true</filtering>
+      </resource>
+    </resources>
     <plugins>
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>

src/main/java/ch/ivyteam/ivy/maven/engine/EngineClassLoaderFactory.java

@@ -26,6 +26,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Properties;
 import java.util.function.Predicate;
 
 import org.apache.maven.artifact.Artifact;
@@ -53,8 +54,7 @@ public interface OsgiDir {
     String LIB_BOOT = "lib/boot";
   }
 
-  /** must match version in pom.xml */
-  private static final String SLF4J_VERSION = "2.0.13";
+  private static final String SLF4J_VERSION = readSlf4jVersion();
 
   private static final List<String> ENGINE_LIB_DIRECTORIES = Arrays.asList(
       OsgiDir.INSTALL_AREA + "/" + OsgiDir.LIB_BOOT,
@@ -90,6 +90,17 @@ public List<File> getSlf4jJars() {
         maven.getJar("org.slf4j", "log4j-over-slf4j", SLF4J_VERSION));
   }
 
+  private static String readSlf4jVersion() {
+    String versions = "versions.properties";
+    try (var in = EngineClassLoaderFactory.class.getResourceAsStream(versions)) {
+      Properties props = new Properties();
+      props.load(in);
+      return props.getProperty("slf4j", "");
+    } catch (IOException ex) {
+      throw new RuntimeException("Failed to read SLF4j version from file: " + versions, ex);
+    }
+  }
+
   public static List<File> getOsgiBootstrapClasspath(Path engineDirectory) {
     if (engineDirectory == null || !Files.isDirectory(engineDirectory)) {
       throw new RuntimeException("The engineDirectory is missing: " + engineDirectory);

src/main/resources-filtered/versions.properties

@@ -0,0 +1 @@
+slf4j=${slf4j.version}