Fix join validation (#31869)

e2e/test/scenarios/joins/reproductions/31769-mlv2-join-dropped.cy.spec.js

+import {
+  popover,
+  restore,
+  startNewQuestion,
+  selectSavedQuestionsToJoin,
+  visualize,
+} from "e2e/support/helpers";
+import { SAMPLE_DATABASE } from "e2e/support/cypress_sample_database";
+
+const { ORDERS, ORDERS_ID, PRODUCTS, PRODUCTS_ID, PEOPLE, PEOPLE_ID } =
+  SAMPLE_DATABASE;
+
+const Q1 = {
+  "source-table": ORDERS_ID,
+  joins: [
+    {
+      fields: "all",
+      alias: "Products",
+      "source-table": PRODUCTS_ID,
+      condition: [
+        "=",
+        ["field", ORDERS.PRODUCT_ID, null],
+        ["field", PRODUCTS.ID, { "join-alias": "Products" }],
+      ],
+    },
+    {
+      fields: "all",
+      alias: "People — User",
+      "source-table": PEOPLE_ID,
+      condition: [
+        "=",
+        ["field", ORDERS.USER_ID, null],
+        ["field", PEOPLE.ID, { "join-alias": "People — User" }],
+      ],
+    },
+  ],
+  aggregation: [["count"]],
+  breakout: [
+    [
+      "field",
+      PRODUCTS.CATEGORY,
+      { "base-type": "type/Text", "join-alias": "Products" },
+    ],
+  ],
+};
+
+const Q2 = {
+  "source-table": PRODUCTS_ID,
+  aggregation: [["count"]],
+  breakout: [["field", PRODUCTS.CATEGORY, { "base-type": "type/Text" }]],
+};
+
+describe("issue 31769", () => {
+  beforeEach(() => {
+    restore();
+    cy.signInAsAdmin();
+
+    cy.createQuestion({ name: "Q1", query: Q1 }).then(() => {
+      cy.createQuestion({ name: "Q2", query: Q2 }).then(response => {
+        cy.wrap(response.body.id).as("card_id_q2");
+        startNewQuestion();
+      });
+    });
+  });
+
+  it("shouldn't drop joins using MLv2 format (metabase#31769)", () => {
+    selectSavedQuestionsToJoin("Q1", "Q2");
+
+    popover().findByText("Products → Category").click();
+    popover().findByText("Category").click();
+
+    visualize();
+
+    // Asserting there're two columns from Q1 and two columns from Q2
+    cy.findAllByTestId("header-cell").should("have.length", 4);
+
+    cy.get("@card_id_q2").then(cardId => {
+      cy.findByTestId("TableInteractive-root")
+        .findByText(`Question ${cardId} → Category`)
+        .should("exist");
+    });
+
+    cy.findByTestId("TableInteractive-root")
+      .findByText("Products → Category")
+      .should("exist");
+  });
+});

frontend/src/metabase-lib/queries/structured/Join.ts

@@ -661,7 +661,9 @@ export default class Join extends MBQLObjectClause {
     const dimensions = [...this.parentDimensions(), ...this.joinDimensions()];
     return dimensions.every(
       dimension =>
-        dimensionOptions.hasDimension(dimension.getMLv1CompatibleDimension()) || // For some GUI queries created in earlier versions of Metabase,
+        dimensionOptions.hasDimension(dimension) ||
+        dimensionOptions.hasDimension(dimension.getMLv1CompatibleDimension()) ||
+        // For some GUI queries created in earlier versions of Metabase,
         // some dimensions are described as field literals
         // Usually it's [ "field", field_numeric_id, null|object ]
         // And field literals look like [ "field", "PRODUCT_ID", {'base-type': 'type/Integer' } ]