Some more checks on ID

Author: Evanthx

temporal-sdk/src/main/java/io/temporal/client/StartNexusOperationOptions.java

@@ -51,11 +51,14 @@ private Builder(StartNexusOperationOptions options) {
     }
 
     /**
-     * Required. Unique identifier for this operation within its namespace. Callers must supply this
-     * explicitly; the SDK does not invent one on the caller's behalf.
+     * Required. Unique identifier for this operation within its namespace.
      */
     public Builder setId(@Nonnull String id) {
-      this.id = Objects.requireNonNull(id, "id");
+      Objects.requireNonNull(id, "id");
+      if (id.isEmpty()) {
+        throw new IllegalArgumentException("id must not be empty");
+      }
+      this.id = id;
       return this;
     }
 
@@ -102,9 +105,9 @@ public Builder setIdConflictPolicy(@Nullable NexusOperationIdConflictPolicy idCo
     }
 
     public StartNexusOperationOptions build() {
-      if (id == null) {
+      if (id == null || id.isEmpty()) {
         throw new IllegalStateException(
-            "StartNexusOperationOptions.Builder.setId(...) must be called with a non-null id "
+            "StartNexusOperationOptions.Builder.setId(...) must be called with a non-empty id "
                 + "before build(); the SDK does not generate operation IDs.");
       }
       return new StartNexusOperationOptions(this);

temporal-sdk/src/test/java/io/temporal/client/StartNexusOperationOptionsTest.java

@@ -0,0 +1,53 @@
+package io.temporal.client;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Pure unit tests for {@link StartNexusOperationOptions.Builder} input validation. ID is required —
+ * callers must supply a non-empty value via {@link StartNexusOperationOptions.Builder#setId} and
+ * the SDK does not invent one on their behalf.
+ */
+public class StartNexusOperationOptionsTest {
+
+  @Test
+  public void buildThrowsWhenIdNotSet() {
+    try {
+      StartNexusOperationOptions.newBuilder().build();
+      Assert.fail("expected IllegalStateException when id is unset");
+    } catch (IllegalStateException expected) {
+      Assert.assertTrue(
+          "error message should mention setId, got: " + expected.getMessage(),
+          expected.getMessage() != null && expected.getMessage().contains("setId"));
+    }
+  }
+
+  @Test
+  public void setIdRejectsNull() {
+    try {
+      StartNexusOperationOptions.newBuilder().setId(null);
+      Assert.fail("expected NullPointerException when setId is called with null");
+    } catch (NullPointerException expected) {
+      // expected
+    }
+  }
+
+  @Test
+  public void setIdRejectsEmpty() {
+    try {
+      StartNexusOperationOptions.newBuilder().setId("");
+      Assert.fail("expected IllegalArgumentException when setId is called with an empty string");
+    } catch (IllegalArgumentException expected) {
+      Assert.assertTrue(
+          "error message should mention empty, got: " + expected.getMessage(),
+          expected.getMessage() != null && expected.getMessage().contains("empty"));
+    }
+  }
+
+  @Test
+  public void buildSucceedsWithNonEmptyId() {
+    StartNexusOperationOptions options =
+        StartNexusOperationOptions.newBuilder().setId("my-id").build();
+    Assert.assertEquals("my-id", options.getId());
+  }
+}