Allow array variables in mail> operator parameters

digdag-standards/src/main/java/io/digdag/standards/operator/MailOperatorFactory.java

@@ -118,13 +118,13 @@ public TaskResult runTask()
 
             List<String> toList;
             try {
-                toList = params.getList("to", String.class);
+                toList = params.parseList("to", String.class);
             }
             catch (ConfigException ex) {
                 toList = ImmutableList.of(params.get("to", String.class));
             }
-            List<String> bccList = params.getListOrEmpty("bcc", String.class);
-            List<String> ccList = params.getListOrEmpty("cc", String.class);
+            List<String> bccList = params.parseListOrGetEmpty("bcc", String.class);
+            List<String> ccList = params.parseListOrGetEmpty("cc", String.class);
 
             boolean isHtml = params.get("html", boolean.class, false);
 

digdag-standards/src/test/java/io/digdag/standards/operator/MailOperatorFactoryTest.java

@@ -354,6 +354,68 @@ public void errorCheckStringBcc()
         }
     }
 
+    @Test
+    public void sendToWithArrayVariable()
+    {
+        // This test simulates what happens when you write:
+        //   _export:
+        //     address_list: ["bob@example.com", "charlie@example.com"]
+        //   +task:
+        //     mail>:
+        //     to: ${address_list}
+        //
+        // After template substitution, the "to" parameter becomes a JSON string like:
+        // '["bob@example.com", "charlie@example.com"]'
+        //
+        // The parseList method should parse this JSON string and convert it to a List
+        Config config = mailConfig.deepCopy();
+        config.set("to", "[\"bob@example.com\", \"charlie@example.com\"]");
+
+        Operator op = factory.newOperator(newContext(
+                tempPath,
+                newTaskRequest().withConfig(config)));
+        op.run();
+        greenMail.waitForIncomingEmail(5000, 2);
+        receiveCheck("bob@example.com", 1);
+        receiveCheck("charlie@example.com", 1);
+    }
+
+    @Test
+    public void sendCcWithArrayVariable()
+    {
+        // After template substitution, the "cc" parameter becomes a JSON string
+        Config config = mailConfig.deepCopy();
+        config.set("to", "bob@example.com");
+        config.set("cc", "[\"charlie@example.com\", \"david@example.com\"]");
+
+        Operator op = factory.newOperator(newContext(
+                tempPath,
+                newTaskRequest().withConfig(config)));
+        op.run();
+        greenMail.waitForIncomingEmail(5000, 3);
+        receiveCheck("bob@example.com", 1);
+        receiveCheck("charlie@example.com", 1);
+        receiveCheck("david@example.com", 1);
+    }
+
+    @Test
+    public void sendBccWithArrayVariable()
+    {
+        // After template substitution, the "bcc" parameter becomes a JSON string
+        Config config = mailConfig.deepCopy();
+        config.set("to", "bob@example.com");
+        config.set("bcc", "[\"charlie@example.com\", \"david@example.com\"]");
+
+        Operator op = factory.newOperator(newContext(
+                tempPath,
+                newTaskRequest().withConfig(config)));
+        op.run();
+        greenMail.waitForIncomingEmail(5000, 3);
+        receiveCheck("bob@example.com", 1);
+        receiveCheck("charlie@example.com", 1);
+        receiveCheck("david@example.com", 1);
+    }
+
     private void receiveCheck(String user, int size)
     {
         AbstractServer server = greenMail.getPop3();