Fix: Initialize Sentry in Logback appender when DSN is not set in XML…

… config (#1296)

* Fix: Start Logback appender when DSN is not set in XML config

Fixes #1295

* changelog.

CHANGELOG.md

@@ -1,6 +1,7 @@
 # vNext
 
 * Fix: Fix setting in-app-includes from external properties (#1291)
+* Fix: Initialize Sentry in Logback appender when DSN is not set in XML config (#1296)
 * Fix: Fix JUL integration SDK name (#1293)
 
 # 4.2.0

sentry-logback/src/main/java/io/sentry/logback/SentryAppender.java

@@ -35,7 +35,7 @@ public final class SentryAppender extends UnsynchronizedAppenderBase<ILoggingEve
   @Override
   public void start() {
     if (!Sentry.isEnabled()) {
-      if (options.getDsn() != null && !options.getDsn().endsWith("_IS_UNDEFINED")) {
+      if (options.getDsn() == null || !options.getDsn().endsWith("_IS_UNDEFINED")) {
         options.setEnableExternalConfiguration(true);
         options.setSentryClientName(BuildConfig.SENTRY_LOGBACK_SDK_NAME);
         options.setSdkVersion(createSdkVersion(options));

sentry-logback/src/test/kotlin/io/sentry/logback/SentryAppenderTest.kt

@@ -308,10 +308,19 @@ class SentryAppenderTest {
     }
 
     @Test
-    fun `does not initialize Sentry when environment variable with DSN is not set`() {
+    fun `does not initialize Sentry when environment variable with DSN is passed through environment variable that is not set`() {
         // environment variables referenced in the logback.xml that are not set in the OS, have value "ENV_NAME_IS_UNDEFINED"
         fixture = Fixture(dsn = "DSN_IS_UNDEFINED", minimumEventLevel = Level.DEBUG)
 
         assertTrue(fixture.loggerContext.statusManager.copyOfStatusList.none { it.level == Status.WARN })
     }
+
+    @Test
+    fun `does initialize Sentry when DSN is not set`() {
+        System.setProperty("sentry.dsn", "http://key@localhost/proj")
+        fixture = Fixture(dsn = null, minimumEventLevel = Level.DEBUG)
+
+        assertTrue(Sentry.isEnabled())
+        System.clearProperty("sentry.dsn")
+    }
 }