XCTL of a value field of the LINKed DTO is refused by name (X39, Part of #5060)

docs/language_status/register/X39.md

@@ -27,8 +27,9 @@ reached: "no (unit-proven on CicsTask, the model-port DTO case included, and the
 - **Model ports (#4956).** A model-port program is LINKed with its caller's DTO object only, no bytes, so `CicsTask.link` marks
   the callee `linkedDto` and `xctl` refuses, by the same name and message, a successful XCTL whose COMMAREA is that DTO or an
   object it holds by reference (a nested group, a table or its element, a list element, a map value, the byte area). A copy
-  (a new object), a failed XCTL, level 1 and the XCTL target's own DTO are not refused. Not detectable, so not refused: a
-  String or number field passed as the COMMAREA (a value, the same as a copy).
+  (a new object), a failed XCTL, level 1 and the XCTL target's own DTO are not refused. A String or number cannot be traced by
+  reference (#5060), so a successful XCTL whose COMMAREA equals a value the DTO holds (any field, nested or primitive) is refused
+  too; an equal-valued copy is over-refused (refuse, never guess), a value the DTO does not hold is not.
 - **Aliases (#4957).** The det port marks an XCTL whose COMMAREA lies inside any LINKAGE 01 record, not only DFHCOMMAREA: a CALLed
   subprogram's USING record (`CALL 'SUB' USING DFHCOMMAREA`) is the LINK caller's storage under another name, and refuses by the
   same runtime check (only when the program was LINKed with a COMMAREA). `SET ADDRESS OF` (direct or through a pointer) is

gitgalaxy/tools/cobol_to_java/cobol_to_java_transaction_forge.py

@@ -5283,13 +5283,19 @@ def commarea_alternative_todos(commarea: dict) -> list[str]:
                 || o instanceof Double || o instanceof Float);
     }
 
-    /** #4956: whether `part` is `whole` or an object `whole` holds (a nested group, a table, an element, a byte
+    /** #5060: a String or number `part` cannot be traced by reference, so it counts when it equals a value `whole`
+     *  holds (an equal-valued copy is refused too: refuse, never guess).
+     *  #4956: whether `part` is `whole` or an object `whole` holds (a nested group, a table, an element, a byte
      *  area), by reference -- what an XCTL of a LINKed program's DTO, or of a part of it, passes. */
     private static boolean within(Object whole, Object part, java.util.IdentityHashMap<Object, Boolean> seen) {
         if (whole == part) {
             return true;
         }
-        if (!aliasable(whole) || seen.put(whole, Boolean.TRUE) != null) {
+        boolean byValue = part != null && !aliasable(part);  // #5060: a value is traced by equality, not identity
+        if (!aliasable(whole)) {
+            return byValue && part.equals(whole);
+        }
+        if (seen.put(whole, Boolean.TRUE) != null) {
             return false;
         }
         Class<?> type = whole.getClass();
@@ -5308,7 +5314,7 @@ def commarea_alternative_todos(commarea: dict) -> list[str]:
         } else if (!type.getName().startsWith("java.")) {
             for (Class<?> k = type; k != null && k != Object.class; k = k.getSuperclass()) {
                 for (java.lang.reflect.Field f : k.getDeclaredFields()) {
-                    if (java.lang.reflect.Modifier.isStatic(f.getModifiers()) || f.getType().isPrimitive()) {
+                    if (java.lang.reflect.Modifier.isStatic(f.getModifiers()) || (f.getType().isPrimitive() && !byValue)) {
                         continue;
                     }
                     try {
@@ -5357,7 +5363,7 @@ def commarea_alternative_todos(commarea: dict) -> list[str]:
                 snapshot.apply(commarea), "resp", resp, "resp2", resp2);
         boolean ofLinkage = xctlOfLinkage;
         xctlOfLinkage = false;
-        boolean ofDto = linkedDto && aliasable(commarea) && within(this.commarea, commarea, new java.util.IdentityHashMap<>());
+        boolean ofDto = linkedDto && commarea != null && within(this.commarea, commarea, new java.util.IdentityHashMap<>());
         if ("NORMAL".equals(resp) && (ofLinkage && callerArea || ofDto)) {
             throw new UnsupportedOperationException("XCTL passing the COMMAREA its LINK caller passed: IBM does not say "
                     + "whether the target addresses the caller's storage or a copy, not modelled");

tests/cobol_mainframe/test_model_link_xctl_4956.py

@@ -6,7 +6,8 @@
 area). IBM (EXEC CICS XCTL, COMMAREA: "the contents of the data-area are passed") does not say whether the target then
 addresses the caller's storage or a copy. A copy (a new object), a failed XCTL, an XCTL at level 1 or of a task's own
 start COMMAREA, and the target of an XCTL passing its own DTO again (a copy of a copy) are not refused. A String or
-number field is a value, not an object the caller holds: it cannot be told from a copy and is passed as it is.
+number cannot be traced by reference (#5060): one equal to a value the DTO holds is refused too, an equal-valued copy
+included (refuse, never guess); a value the DTO does not hold is passed as it is.
 """
 
 from __future__ import annotations
@@ -62,6 +63,12 @@
                         case "mapped" -> d.byKey.get("k");
                         case "bytes" -> d.raw;
                         case "name" -> d.name;
+                        case "number" -> d.num;
+                        case "nested" -> d.grp.text;
+                        case "tabled" -> d.table[1].text;
+                        case "keyed" -> d.byKey.get("k").text;
+                        case "fresh" -> "zzz";
+                        case "none" -> null;
                         case "copy", "hop" -> new Dto();
                         default -> d;
                     };
@@ -96,7 +103,10 @@
         for (String s : new String[] {"whole", "group", "table", "element", "listed", "mapped", "bytes"}) {
             System.out.println(s + " " + run(s, false, true));
         }
-        for (String s : new String[] {"name", "copy", "failed", "hop"}) {
+        for (String s : new String[] {"name", "number", "nested", "tabled", "keyed"}) {
+            System.out.println(s + " " + run(s, false, true));
+        }
+        for (String s : new String[] {"copy", "fresh", "none", "failed", "hop"}) {
             System.out.println(s + " " + run(s, false, true));
         }
         System.out.println("level1 " + run("whole", true, true));
@@ -114,7 +124,8 @@ def _jdk() -> Path | None:
 @pytest.mark.skipif(_jdk() is None, reason="no JDK (JDK_17 / JAVA_HOME)")
 def test_cictask_refuses_an_xctl_of_the_dto_its_program_was_linked_with(tmp_path):
     """The whole DTO and every object it holds (group, table, element, list element, map value, byte area) are the
-    caller's storage: refused. A copy, a failed XCTL (the program goes on), a String field (a value), a copy-of-a-copy
+    caller's storage: refused; so is a String or number equal to a value the DTO holds (#5060: a value cannot be traced,
+    so an equal-valued copy is refused too). A copy, a distinct value, no COMMAREA, a failed XCTL (the program goes on), a copy-of-a-copy
     hop, a level-1 task and a LINK that passed no DTO are not; the DTO holding itself does not loop."""
     from gitgalaxy.tools.cobol_to_java.cobol_to_java_transaction_forge import CICS_SPEC_JAVA, CICS_TASK_JAVA
 
@@ -138,8 +149,14 @@ def test_cictask_refuses_an_xctl_of_the_dto_its_program_was_linked_with(tmp_path
         "listed REFUSED true",
         "mapped REFUSED true",
         "bytes REFUSED true",
-        "name NORMAL>EE",
+        "name REFUSED true",
+        "number REFUSED true",
+        "nested REFUSED true",
+        "tabled REFUSED true",
+        "keyed REFUSED true",
         "copy NORMAL>EE",
+        "fresh NORMAL>EE",
+        "none NORMAL>EE",
         "failed PGMIDERR",
         "hop NORMAL>EE",
         "level1 NORMAL>EE",