Commit cancel, resume and delete with their checkpoint, and refuse a self-target

transact/src/main/java/dev/dbos/transact/DBOS.java

@@ -872,6 +872,8 @@ public <E extends Exception> void runStep(
    *     will be resumed in the default execution context
    * @return A handle to the resumed workflow
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being resumed, or one of
+   *     its steps: a workflow can't resume itself. Nothing is resumed.
    */
   @SuppressWarnings("unchecked")
   public <T, E extends Exception> @NonNull WorkflowHandle<T, E> resumeWorkflow(
@@ -892,6 +894,8 @@ public <E extends Exception> void runStep(
    * @param workflowId ID of the workflow to resume; must not be null
    * @return A handle to the resumed workflow
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being resumed, or one of
+   *     its steps: a workflow can't resume itself. Nothing is resumed.
    */
   public <T, E extends Exception> @NonNull WorkflowHandle<T, E> resumeWorkflow(
       @NonNull String workflowId) {
@@ -909,6 +913,8 @@ public <E extends Exception> void runStep(
    *     workflows will be resumed in the default execution context
    * @return A list of handles to the resumed workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being resumed, or
+   *     one of its steps: a workflow can't resume itself. Nothing is resumed.
    */
   public @NonNull List<WorkflowHandle<Object, Exception>> resumeWorkflows(
       @NonNull List<String> workflowIds, @Nullable String queueName) {
@@ -924,6 +930,8 @@ public <E extends Exception> void runStep(
    * @param workflowIds a list of workflow IDs to resume; must not be null
    * @return A list of handles to the resumed workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being resumed, or
+   *     one of its steps: a workflow can't resume itself. Nothing is resumed.
    */
   public @NonNull List<WorkflowHandle<Object, Exception>> resumeWorkflows(
       @NonNull List<String> workflowIds) {
@@ -937,6 +945,8 @@ public <E extends Exception> void runStep(
    *
    * @param workflowId ID of the workflow to cancel
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being cancelled, or one of
+   *     its steps: a workflow can't cancel itself. Nothing is cancelled.
    */
   public void cancelWorkflow(@NonNull String workflowId) {
     cancelWorkflows(List.of(workflowId), false);
@@ -948,6 +958,9 @@ public void cancelWorkflow(@NonNull String workflowId) {
    * @param workflowId ID of the workflow to cancel
    * @param cancelChildren if true, recursively cancel all descendant workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being cancelled, or one of
+   *     its steps, or, when {@code cancelChildren}, from inside one of its descendants: a workflow
+   *     can't cancel itself or a tree it belongs to. Nothing is cancelled.
    */
   public void cancelWorkflow(@NonNull String workflowId, boolean cancelChildren) {
     cancelWorkflows(List.of(workflowId), cancelChildren);
@@ -959,6 +972,8 @@ public void cancelWorkflow(@NonNull String workflowId, boolean cancelChildren) {
    *
    * @param workflowIds a list of workflow IDs to cancel; must not be null
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being cancelled, or
+   *     one of its steps: a workflow can't cancel itself. Nothing is cancelled.
    */
   public void cancelWorkflows(@NonNull List<String> workflowIds) {
     cancelWorkflows(workflowIds, false);
@@ -970,6 +985,9 @@ public void cancelWorkflows(@NonNull List<String> workflowIds) {
    * @param workflowIds a list of workflow IDs to cancel; must not be null
    * @param cancelChildren if true, recursively cancel all descendant workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being cancelled, or
+   *     one of its steps, or, when {@code cancelChildren}, from inside one of their descendants: a
+   *     workflow can't cancel itself or a tree it belongs to. Nothing is cancelled.
    */
   public void cancelWorkflows(@NonNull List<String> workflowIds, boolean cancelChildren) {
     ensureLaunched("cancelWorkflows").cancelWorkflows(workflowIds, cancelChildren);
@@ -981,6 +999,8 @@ public void cancelWorkflows(@NonNull List<String> workflowIds, boolean cancelChi
    *
    * @param workflowId ID of the workflow to delete; must not be null
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being deleted, or one of
+   *     its steps: a workflow can't delete itself. Nothing is deleted.
    */
   public void deleteWorkflow(@NonNull String workflowId) {
     deleteWorkflows(List.of(workflowId), false);
@@ -994,6 +1014,9 @@ public void deleteWorkflow(@NonNull String workflowId) {
    * @param deleteChildren if true, also delete any child workflows; if false, preserve child
    *     workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside the workflow being deleted, or one of
+   *     its steps, or, when {@code deleteChildren}, from inside one of its descendants: a workflow
+   *     can't delete itself or a tree it belongs to. Nothing is deleted.
    */
   public void deleteWorkflow(@NonNull String workflowId, boolean deleteChildren) {
     deleteWorkflows(List.of(workflowId), deleteChildren);
@@ -1005,6 +1028,8 @@ public void deleteWorkflow(@NonNull String workflowId, boolean deleteChildren) {
    *
    * @param workflowIds a list of workflow IDs to delete; must not be null
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being deleted, or
+   *     one of its steps: a workflow can't delete itself. Nothing is deleted.
    */
   public void deleteWorkflows(@NonNull List<String> workflowIds) {
     deleteWorkflows(workflowIds, false);
@@ -1018,6 +1043,9 @@ public void deleteWorkflows(@NonNull List<String> workflowIds) {
    * @param deleteChildren if true, also delete any child workflows; if false, preserve child
    *     workflows
    * @throws IllegalStateException if called before DBOS is launched
+   * @throws IllegalArgumentException if called from inside one of the workflows being deleted, or
+   *     one of its steps, or, when {@code deleteChildren}, from inside one of their descendants: a
+   *     workflow can't delete itself or a tree it belongs to. Nothing is deleted.
    */
   public void deleteWorkflows(@NonNull List<String> workflowIds, boolean deleteChildren) {
     ensureLaunched("deleteWorkflows").deleteWorkflows(workflowIds, deleteChildren);

transact/src/main/java/dev/dbos/transact/DBOSClient.java

@@ -1597,7 +1597,7 @@ public void cancelWorkflows(@NonNull List<String> workflowIds) {
    * @param cancelChildren if true, recursively cancel all descendant workflows
    */
   public void cancelWorkflows(@NonNull List<String> workflowIds, boolean cancelChildren) {
-    systemDatabase.cancelWorkflows(workflowIds, cancelChildren);
+    systemDatabase.cancelWorkflows(workflowIds, cancelChildren, null);
   }
 
   /**
@@ -1627,7 +1627,7 @@ public void updateWorkflowAttributes(
    */
   public <T, E extends Exception> @NonNull WorkflowHandle<T, E> resumeWorkflow(
       @NonNull String workflowId, @Nullable String queueName) {
-    systemDatabase.resumeWorkflows(List.of(workflowId), queueName);
+    systemDatabase.resumeWorkflows(List.of(workflowId), queueName, null);
     return retrieveWorkflow(workflowId);
   }
 
@@ -1674,7 +1674,7 @@ public void updateWorkflowAttributes(
    */
   public @NonNull List<WorkflowHandle<Object, Exception>> resumeWorkflows(
       @NonNull List<String> workflowIds, @Nullable String queueName) {
-    systemDatabase.resumeWorkflows(workflowIds, queueName);
+    systemDatabase.resumeWorkflows(workflowIds, queueName, null);
     return workflowIds.stream().map(this::retrieveWorkflow).toList();
   }
 
@@ -1719,7 +1719,7 @@ public void deleteWorkflows(@NonNull List<String> workflowIds) {
    *     workflows
    */
   public void deleteWorkflows(@NonNull List<String> workflowIds, boolean deleteChildren) {
-    systemDatabase.deleteWorkflows(workflowIds, deleteChildren);
+    systemDatabase.deleteWorkflows(workflowIds, deleteChildren, null);
   }
 
   /**

transact/src/main/java/dev/dbos/transact/database/StepCaller.java

@@ -0,0 +1,22 @@
+package dev.dbos.transact.database;
+
+/**
+ * The workflow execution a DBOS operation, such as a send or a cancel, is made from. The operation
+ * lands only while that execution still owns the workflow.
+ */
+public sealed interface StepCaller {
+  /** The calling workflow. */
+  String workflowId();
+
+  /** The token of the calling workflow's execution. */
+  String ownerXid();
+
+  /** A call from the workflow body, recorded as the workflow's step {@code stepId}. */
+  record FromWorkflow(String workflowId, int stepId, String ownerXid) implements StepCaller {}
+
+  /**
+   * A call from inside a step, which records nothing of its own but is still checked against the
+   * owner.
+   */
+  record FromStep(String workflowId, String ownerXid) implements StepCaller {}
+}