Fix table columns remapped fields (#39798)

e2e/test/scenarios/question/reproductions/39795-reorder-column-field-mapping.cy.spec.js

+import { SAMPLE_DB_ID } from "e2e/support/cypress_data";
+import { SAMPLE_DATABASE } from "e2e/support/cypress_sample_database";
+import {
+  getDraggableElements,
+  moveColumnDown,
+  visitQuestionAdhoc,
+  restore,
+} from "e2e/support/helpers";
+
+const { ORDERS, ORDERS_ID, PRODUCTS } = SAMPLE_DATABASE;
+
+describe("issue 39795", () => {
+  beforeEach(() => {
+    restore();
+    cy.signInAsAdmin();
+
+    //If you comment out this post, then the test will pass.
+    cy.request("post", `/api/field/${ORDERS.PRODUCT_ID}/dimension`, {
+      human_readable_field_id: PRODUCTS.TITLE,
+      name: "Product ID",
+      type: "external",
+    });
+  });
+
+  it("should allow me to re-order even when a field is set with a different display value (metabase#39795)", () => {
+    visitQuestionAdhoc({
+      dataset_query: {
+        database: SAMPLE_DB_ID,
+        query: {
+          "source-table": ORDERS_ID,
+        },
+        type: "query",
+      },
+    });
+    cy.findByTestId("viz-settings-button").click();
+    moveColumnDown(getDraggableElements().first(), 2);
+
+    // We are not able to re-order because the dataset will also contain values a column for Product ID
+    // This causes the isValid() check to fire, and you are always forced into the default value for table.columns
+    getDraggableElements().eq(2).should("contain.text", "ID");
+  });
+});

frontend/src/metabase-lib/Question.ts

@@ -515,7 +515,7 @@ class Question {
     return this;
   }
 
-  _syncTableColumnSettings({ data: { cols = [] } = {} }: Dataset) {
+  _syncTableColumnSettings({ data = {} }: Dataset) {
     const columnSettings = this.setting("table.columns") || [];
     // "table.columns" receive a value only if there are custom settings
     // e.g. some columns are hidden. If it's empty, it means everything is visible
@@ -524,6 +524,8 @@ class Question {
       return this;
     }
 
+    // remove columns used for remapping only
+    const cols = data.cols.filter(col => col.remapped_from == null);
     const columnIndexes = findColumnIndexesForColumnSettings(
       cols,
       columnSettings,