fix(workbook): honor stable column IDs in structural edit guards

apps/api/services/workbook/column_deps.py

@@ -94,9 +94,14 @@ def referencing_columns(cols: List[dict], column: dict) -> List[dict]:
     """
     normalize = lambda value: str(value).strip().lower().replace("_", " ")
     aliases = {normalize(column[key]) for key in ("id", "name") if column.get(key)}
+    stable_ids = {candidate.get("id") for candidate in cols if candidate.get("id")}
     return [candidate for candidate in cols
             if candidate.get("id") != column.get("id")
-            and aliases.intersection(normalize(ref) for ref in _refs_in(candidate))]
+            and any(
+                (ref == column.get("id") if ref in stable_ids
+                 else normalize(ref) in aliases)
+                for ref in _refs_in(candidate)
+            )]
 
 
 def broken_rename_references(before: List[dict], after: List[dict]) -> List[dict]:
@@ -116,8 +121,12 @@ def broken_rename_references(before: List[dict], after: List[dict]) -> List[dict
         aliases = {normalize(column[key]) for key in ("id", "name") if column.get(key)}
         if name not in aliases:
             lost.add(name)
+    # Stable IDs take precedence over display aliases during execution. A
+    # retained ID cannot be broken by renaming another column's display name.
+    retained_ids = {column.get("id") for column in after if column.get("id")}
     return [column for column in after
-            if lost.intersection(normalize(ref) for ref in _refs_in(column))]
+            if any(ref not in retained_ids and normalize(ref) in lost
+                   for ref in _refs_in(column))]
 
 
 def cycle_blocked_columns(columns: List[dict]) -> set:

tests/test_column_deps.py

@@ -166,3 +166,32 @@ def test_formula_dependencies_share_escaped_and_triple_quote_rules():
     formula = 'concat("escaped \\"{literal}\\"", """{multiline}\ntext""", { Owner\'s Name })'
     assert _refs_in({"formula": formula}) == {"Owner's Name"}
     assert _refs_in({"formula": "{self}"}) == {"self"}
+
+
+def test_structure_guards_preserve_stable_id_precedence_over_display_names():
+    from apps.api.services.workbook.column_deps import referencing_columns, broken_rename_references
+    columns = [
+        {"id": "display", "name": "source", "type": "input"},
+        {"id": "source", "name": "Real", "type": "input"},
+        {"id": "derived", "type": "formula", "formula": "{source}"},
+    ]
+    assert referencing_columns(columns, columns[0]) == []
+    assert referencing_columns(columns, columns[1]) == [columns[2]]
+    # Whole-config replacement checks retain the same ID authority.
+    assert referencing_columns(columns[1:], columns[0]) == []
+    renamed = [dict(column, name="Renamed") if column["id"] == "display"
+               else dict(column) for column in columns]
+    assert broken_rename_references(columns, renamed) == []
+
+
+def test_structure_guards_still_block_ambiguous_display_alias_retargeting():
+    from apps.api.services.workbook.column_deps import referencing_columns, broken_rename_references
+    columns = [
+        {"id": "first", "name": "Shared", "type": "input"},
+        {"id": "second", "name": "Shared", "type": "input"},
+        {"id": "derived", "type": "formula", "formula": "{Shared}"},
+    ]
+    assert referencing_columns(columns, columns[0]) == [columns[2]]
+    renamed = [dict(column, name="Renamed") if column["id"] == "first"
+               else dict(column) for column in columns]
+    assert broken_rename_references(columns, renamed) == [renamed[2]]

tests/test_workbook_views.py

@@ -2845,3 +2845,27 @@ def test_duplicate_display_alias_rejects_ambiguous_public_reference(client, comp
         assert row.enrichments["result"]["status"] == "error"
         assert row.enrichments["result"]["error"] == "ambiguous_column_reference"
         assert row.enrichments["result"]["value"] is None
+
+
+@pytest.mark.parametrize("operation", ["delete", "rename", "replace"])
+def test_structure_edit_does_not_redirect_or_block_another_stable_id(client, operation):
+    tc, Session, _ = client
+    columns = [
+        {"id": "display", "name": "source", "type": "input", "width": 200},
+        {"id": "source", "name": "Actual source", "type": "input", "width": 200},
+        {"id": "derived", "name": "Derived", "type": "formula", "formula": "{source}", "width": 200},
+    ]
+    wid = _mk_workbook(Session, columns)
+    if operation == "delete":
+        response = tc.delete(f"/api/workbooks/{wid}/columns/display")
+    elif operation == "rename":
+        response = tc.patch(f"/api/workbooks/{wid}/columns/display/settings", json={
+            "changes": {"name": "Renamed"}, "expected": {"name": "source"}})
+    else:
+        response = tc.put(f"/api/workbooks/{wid}", json={"columns_config": columns[1:]})
+    assert response.status_code == 200, response.text
+    with Session() as db:
+        stored = db.get(Workbook, wid).columns_config
+        assert next(c for c in stored if c["id"] == "source") == columns[1]
+        assert next(c for c in stored if c["id"] == "derived")["formula"] == "{source}"
+        assert db.query(Job).count() == 0