Give DebugBreakpointNode some section to prevent NPE (#11594)

Fixes `NullPointerException` by giving `DebugBreakpointNode` a source section.

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/DebuggingEnsoTest.java

@@ -317,6 +317,41 @@ public class DebuggingEnsoTest {
     }
   }
 
+  @Test
+  public void testEvaluateExpressionInDebugBreakpoint() {
+    Value fooFunc =
+        createEnsoMethod(
+            """
+
+        import Standard.Base.Runtime.Debug
+
+        foo x =
+            a = 6
+            b = 7
+            Debug.breakpoint
+        """,
+            "foo");
+
+    int[] res = {0};
+    try (DebuggerSession session =
+        debugger.startSession(
+            (SuspendedEvent event) -> {
+              switch (event.getSourceSection().getCharacters().toString().strip()) {
+                case "Debug.breakpoint" -> {
+                  DebugStackFrame stackFrame = event.getTopStackFrame();
+                  DebugValue evaluatedValue = stackFrame.eval("a * b");
+                  assertTrue(evaluatedValue.isNumber());
+                  assertEquals(42, res[0] = evaluatedValue.asInt());
+                }
+              }
+              event.getSession().suspendNextExecution();
+            })) {
+      session.suspendNextExecution();
+      fooFunc.execute(0);
+    }
+    assertEquals("Really suspended at 42", 42, res[0]);
+  }
+
   @Test
   public void testRewriteLocalVariable() {
     Value fooFunc =

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/debug/DebugBreakpointNode.java

@@ -8,6 +8,8 @@ import com.oracle.truffle.api.instrumentation.InstrumentableNode;
 import com.oracle.truffle.api.instrumentation.ProbeNode;
 import com.oracle.truffle.api.instrumentation.Tag;
 import com.oracle.truffle.api.nodes.Node;
+import com.oracle.truffle.api.source.Source;
+import com.oracle.truffle.api.source.SourceSection;
 import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.runtime.EnsoContext;
 import org.enso.interpreter.runtime.callable.CallerInfo;
@@ -20,6 +22,13 @@ import org.enso.interpreter.runtime.state.State;
     autoRegister = false)
 @GenerateWrapper
 public abstract class DebugBreakpointNode extends Node implements InstrumentableNode {
+  private static final SourceSection DEBUG_SECTION;
+
+  static {
+    var src = Source.newBuilder("enso", "Debug.breakpoint", "Debug.enso").build();
+    DEBUG_SECTION = src.createUnavailableSection();
+  }
+
   /**
    * Creates a new instance of this node.
    *
@@ -29,13 +38,18 @@ public abstract class DebugBreakpointNode extends Node implements Instrumentable
     return DebugBreakpointNodeGen.create();
   }
 
+  @Override
+  public final SourceSection getSourceSection() {
+    return DEBUG_SECTION;
+  }
+
   /**
    * Tells Truffle this node is instrumentable.
    *
    * @return {@code true} – this node is always instrumentable.
    */
   @Override
-  public boolean isInstrumentable() {
+  public final boolean isInstrumentable() {
     return true;
   }
 
@@ -55,7 +69,7 @@ public abstract class DebugBreakpointNode extends Node implements Instrumentable
    * @return {@code true} if the tag is {@link DebuggerTags.AlwaysHalt}, {@code false} otherwise
    */
   @Override
-  public boolean hasTag(Class<? extends Tag> tag) {
+  public final boolean hasTag(Class<? extends Tag> tag) {
     return tag == DebuggerTags.AlwaysHalt.class;
   }
 
@@ -66,7 +80,7 @@ public abstract class DebugBreakpointNode extends Node implements Instrumentable
    * @return the wrapper instance wrapping both this and the probe node
    */
   @Override
-  public WrapperNode createWrapper(ProbeNode probeNode) {
+  public final WrapperNode createWrapper(ProbeNode probeNode) {
     return new DebugBreakpointNodeWrapper(this, probeNode);
   }
 }