ref(core): Remove force new trace transaction flag

Use parent span presence as the session trace lifecycle opt-out instead of a separate TransactionContext flag.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry/api/sentry.api

@@ -4593,9 +4593,7 @@ public final class io/sentry/TransactionContext : io/sentry/SpanContext {
 	public fun getParentSamplingDecision ()Lio/sentry/TracesSamplingDecision;
 	public fun getTransactionNameSource ()Lio/sentry/protocol/TransactionNameSource;
 	public fun isForNextAppStart ()Z
-	public fun isForceNewTrace ()Z
 	public fun setForNextAppStart (Z)V
-	public fun setForceNewTrace (Z)V
 	public fun setName (Ljava/lang/String;)V
 	public fun setParentSampled (Ljava/lang/Boolean;)V
 	public fun setParentSampled (Ljava/lang/Boolean;Ljava/lang/Boolean;)V

sentry/src/main/java/io/sentry/Scopes.java

@@ -1027,8 +1027,7 @@ && getOptions().getProfileLifecycle() == ProfileLifecycle.TRACE
     final @NotNull PropagationContext propagationContext =
         getCombinedScopeView().getPropagationContext();
     if (getOptions().isEnableSessionTraceLifecycle()
-        && transactionContext.getParentSpanId() == null
-        && !transactionContext.isForceNewTrace()) {
+        && transactionContext.getParentSpanId() == null) {
       return TransactionContext.fromPropagationContextAsRoot(
           propagationContext, transactionContext);
     }

sentry/src/main/java/io/sentry/TransactionContext.java

@@ -17,7 +17,6 @@ public final class TransactionContext extends SpanContext {
   private @NotNull TransactionNameSource transactionNameSource;
   private @Nullable TracesSamplingDecision parentSamplingDecision;
   private boolean isForNextAppStart = false;
-  private boolean forceNewTrace = false;
 
   @ApiStatus.Internal
   public static TransactionContext fromPropagationContext(
@@ -57,7 +56,6 @@ public static TransactionContext fromPropagationContext(
     sessionContext.transactionNameSource = transactionContext.transactionNameSource;
     sessionContext.parentSamplingDecision = transactionContext.parentSamplingDecision;
     sessionContext.isForNextAppStart = transactionContext.isForNextAppStart;
-    sessionContext.forceNewTrace = transactionContext.forceNewTrace;
     return sessionContext;
   }
 
@@ -169,28 +167,6 @@ public void setTransactionNameSource(final @NotNull TransactionNameSource transa
     this.transactionNameSource = transactionNameSource;
   }
 
-  /**
-   * Forces this transaction to start a new trace when session trace lifecycle is enabled.
-   * Explicitly continued traces with a parent span are still preserved.
-   *
-   * @return true if this transaction should not reuse the session propagation context.
-   */
-  @ApiStatus.Experimental
-  public boolean isForceNewTrace() {
-    return forceNewTrace;
-  }
-
-  /**
-   * Forces this transaction to start a new trace when session trace lifecycle is enabled.
-   * Explicitly continued traces with a parent span are still preserved.
-   *
-   * @param forceNewTrace true to keep this transaction on a new trace.
-   */
-  @ApiStatus.Experimental
-  public void setForceNewTrace(final boolean forceNewTrace) {
-    this.forceNewTrace = forceNewTrace;
-  }
-
   @ApiStatus.Internal
   public void setForNextAppStart(final boolean forNextAppStart) {
     isForNextAppStart = forNextAppStart;

sentry/src/test/java/io/sentry/ScopesTest.kt

@@ -1837,24 +1837,11 @@ class ScopesTest {
   }
 
   @Test
-  fun `when session trace lifecycle is enabled, forceNewTrace keeps transaction trace`() {
-    val scopes = generateScopes { it.isEnableSessionTraceLifecycle = true }
-    val context = TransactionContext("name", "op")
-    context.setForceNewTrace(true)
-
-    val transaction = scopes.startTransaction(context)
-
-    assertTrue(transaction is SentryTracer)
-    assertEquals(context.traceId, transaction.root.spanContext.traceId)
-  }
-
-  @Test
-  fun `forceNewTrace does not override continued trace with parent span`() {
+  fun `continued trace with parent span is not remapped to session trace`() {
     val scopes = generateScopes { it.isEnableSessionTraceLifecycle = true }
     val traceId = "75302ac48a024bde9a3b3734a82e36c8"
     val parentSpanId = "1000000000000000"
     val context = scopes.continueTrace("$traceId-$parentSpanId-1", emptyList())!!
-    context.setForceNewTrace(true)
 
     val transaction = scopes.startTransaction(context)