Check for mixed SDK versions

Author: adinauer

sentry/src/main/java/io/sentry/SentryClient.java

@@ -767,6 +767,9 @@ public void captureSession(final @NotNull Session session, final @Nullable Hint
             .log(SentryLevel.ERROR, "The BeforeEnvelope callback threw an exception.", e);
       }
     }
+
+    SentryIntegrationPackageStorage.getInstance().checkForMixedVersions(options.getLogger());
+
     if (hint == null) {
       transport.send(envelope);
     } else {

sentry/src/main/java/io/sentry/SentryIntegrationPackageStorage.java

@@ -5,6 +5,7 @@
 import io.sentry.util.Objects;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArraySet;
+
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -15,6 +16,8 @@ public final class SentryIntegrationPackageStorage {
   private static volatile @Nullable SentryIntegrationPackageStorage INSTANCE;
   private static final @NotNull AutoClosableReentrantLock staticLock =
       new AutoClosableReentrantLock();
+  private static volatile @Nullable Boolean mixedVersionsDetected = null;
+  private static final @NotNull AutoClosableReentrantLock mixedVersionsLock = new AutoClosableReentrantLock();
 
   public static @NotNull SentryIntegrationPackageStorage getInstance() {
     if (INSTANCE == null) {
@@ -64,12 +67,42 @@ public void addPackage(final @NotNull String name, final @NotNull String version
 
     SentryPackage newPackage = new SentryPackage(name, version);
     packages.add(newPackage);
+    try (final @NotNull ISentryLifecycleToken ignored = mixedVersionsLock.acquire()) {
+      mixedVersionsDetected = null;
+    }
   }
 
   public @NotNull Set<SentryPackage> getPackages() {
     return packages;
   }
 
+  public boolean checkForMixedVersions(final @NotNull ILogger logger) {
+    final @Nullable Boolean mixedVersionsDetectedBefore = mixedVersionsDetected;
+    if (mixedVersionsDetectedBefore != null) {
+      return mixedVersionsDetectedBefore;
+    }
+    try (final @NotNull ISentryLifecycleToken ignored = mixedVersionsLock.acquire()) {
+      final @NotNull String sdkVersion = BuildConfig.VERSION_NAME;
+      boolean mixedVersionsDetectedThisCheck = false;
+
+      for (SentryPackage pkg : packages) {
+        if (pkg.getName().startsWith("maven:io.sentry:") && !sdkVersion.equalsIgnoreCase(pkg.getVersion())) {
+          logger.log(SentryLevel.ERROR, "The Sentry SDK has been configured with mixed versions. Expected %s to match core SDK version %s but was %s", pkg.getName(), sdkVersion, pkg.getVersion());
+          mixedVersionsDetectedThisCheck = true;
+        }
+      }
+
+      if (mixedVersionsDetectedThisCheck) {
+        logger.log(SentryLevel.ERROR, "^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
+        logger.log(SentryLevel.ERROR, "^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
+        logger.log(SentryLevel.ERROR, "^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
+        logger.log(SentryLevel.ERROR, "^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
+      }
+      mixedVersionsDetected = mixedVersionsDetectedThisCheck;
+      return mixedVersionsDetectedThisCheck;
+    }
+  }
+
   @TestOnly
   public void clearStorage() {
     integrations.clear();