fix: migrate legacy dir.logs log4j property

Fixes a crash on boot caused by dir.logs set in log4j2.properties, which
is not supported in log4j2.  Cannot use normal migration infra since
log4j is initialized early in the boot processs (before classpath is
fully set up).

Issue: #267
Signed-off-by: Mitch Gaffigan <mgaffigan@users.noreply.github.com>

Author: Copilot

server/src/com/mirth/connect/server/launcher/MirthLauncher.java

@@ -15,6 +15,7 @@
 import java.io.IOException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -40,11 +41,13 @@ public class MirthLauncher {
     private static final String EXTENSIONS_DIR = "./extensions";
     private static final String SERVER_LAUNCHER_LIB_DIR = "./server-launcher-lib";
     private static final String MIRTH_PROPERTIES_FILE = "./conf/mirth.properties";
+    private static final String LOG4J_PROPERTIES_FILE = "./conf/log4j2.properties";
     private static final String PROPERTY_APP_DATA_DIR = "dir.appdata";
     private static final String PROPERTY_INCLUDE_CUSTOM_LIB = "server.includecustomlib";
     private static final String[] LOG4J_JAR_FILES = { "./server-lib/log4j/log4j-core-2.25.3.jar",
             "./server-lib/log4j/log4j-api-2.25.3.jar",
             "./server-lib/log4j/log4j-1.2-api-2.25.3.jar" };
+    private static final String INVALID_LOG4J_PROPERTY = "dir.logs";
 
     private static String appDataDir = null;
 
@@ -53,6 +56,8 @@ public class MirthLauncher {
     public static void main(String[] args) {
         JarFile mirthClientCoreJarFile = null;
         try {
+            sanitizeLog4jConfiguration(new File(LOG4J_PROPERTIES_FILE));
+
             List<URL> classpathUrls = new ArrayList<>();
             // Always add log4j
             for (String log4jJar : LOG4J_JAR_FILES) {
@@ -128,6 +133,28 @@ public static void main(String[] args) {
         }
     }
 
+    private static void sanitizeLog4jConfiguration(File propertiesFile) {
+        if (!propertiesFile.exists() || !propertiesFile.isFile()) {
+            return;
+        }
+
+        try {
+            List<String> lines = FileUtils.readLines(propertiesFile, StandardCharsets.UTF_8);
+            if (lines.removeIf(MirthLauncher::isInvalidLog4jPropertyLine)) {
+                FileUtils.writeLines(propertiesFile, StandardCharsets.UTF_8.name(), lines, System.lineSeparator(), false);
+            }
+        } catch (IOException e) {
+            System.err.println("Failed to sanitize Log4j configuration: " + propertiesFile.getAbsolutePath());
+            e.printStackTrace();
+        }
+    }
+
+    private static boolean isInvalidLog4jPropertyLine(String line) {
+        String trimmedLine = line.trim();
+        int equalsIndex = trimmedLine.indexOf('=');
+        return equalsIndex >= 0 && trimmedLine.substring(0, equalsIndex).trim().equals(INVALID_LOG4J_PROPERTY);
+    }
+
     // if we have an uninstall file, uninstall the listed extensions
     private static void uninstallPendingExtensions() throws Exception {
         File extensionsDir = new File(EXTENSIONS_DIR);

server/test/com/mirth/connect/server/launcher/MirthLauncherTest.java

@@ -0,0 +1,34 @@
+package com.mirth.connect.server.launcher;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.lang.reflect.Method;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+import org.junit.Test;
+
+public class MirthLauncherTest {
+
+    @Test
+    public void testSanitizeLog4jRemovesDirLogs() throws Exception {
+        File file = File.createTempFile("log4j2", ".properties");
+        file.deleteOnExit();
+        Files.writeString(file.toPath(), String.join(System.lineSeparator(),
+                "rootLogger = ERROR,stdout,fout",
+                "dir.logs   = logs",
+                "property.log.dir = logs",
+                "appender.rolling.fileName = ${log.dir}/mirth.log"), StandardCharsets.UTF_8);
+
+        Method method = MirthLauncher.class.getDeclaredMethod("sanitizeLog4jConfiguration", File.class);
+        method.setAccessible(true);
+        method.invoke(null, file);
+
+        String fileContents = Files.readString(file.toPath(), StandardCharsets.UTF_8);
+        assertFalse(fileContents.contains("dir.logs"));
+        assertTrue(fileContents.contains("property.log.dir = logs"));
+        assertTrue(fileContents.contains("appender.rolling.fileName = ${log.dir}/mirth.log"));
+    }
+}