[MLv2] Fix join clause dispatches for card and table sources (#32769)

src/metabase/lib/join.cljc

@@ -335,6 +335,20 @@
        :stages   [mbql-stage]}
       lib.options/ensure-uuid))
 
+(defmethod join-clause-method :metadata/card
+  [card]
+  (-> {:lib/type :mbql/join
+       :stages [{:source-card (:id card)
+                 :lib/type :mbql.stage/mbql}]}
+      lib.options/ensure-uuid))
+
+(defmethod join-clause-method :metadata/table
+  [table]
+  (-> {:lib/type :mbql/join
+       :stages [{:source-table (:id table)
+                 :lib/type :mbql.stage/mbql}]}
+      lib.options/ensure-uuid))
+
 (defn- with-join-conditions-add-alias-to-rhses
   "Add `join-alias` to the RHS of all [[standard-join-condition?]] `conditions` that don't already have a `:join-alias`.
   If an RHS already has a `:join-alias`, don't second guess what was already explicitly specified."

test/metabase/lib/join_test.cljc

@@ -63,7 +63,29 @@
                             :source-table (meta/id :orders)}]
              :lib/options {:lib/uuid string?}
              :fields      :all}
-            (lib/join-clause (meta/table-metadata :orders))))))
+            (lib/join-clause (meta/table-metadata :orders)))))
+  (testing "source-card"
+    (let [query {:lib/type :mbql/query
+                 :lib/metadata lib.tu/metadata-provider-with-mock-cards
+                 :database (meta/id)
+                 :stages [{:lib/type :mbql.stage/mbql
+                           :source-card (:id (lib.tu/mock-cards :orders))}]}
+          product-card (lib.tu/mock-cards :products)
+          [_ orders-product-id] (lib/join-condition-lhs-columns query product-card nil nil)
+          [products-id] (lib/join-condition-rhs-columns query product-card orders-product-id nil)]
+      (is (=? {:stages [{:joins [{:stages [{:source-card (:id product-card)}]}]}]}
+          (lib/join query (lib/join-clause product-card [(lib/= orders-product-id products-id)]))))))
+  (testing "source-table"
+    (let [query {:lib/type :mbql/query
+                 :lib/metadata lib.tu/metadata-provider-with-mock-cards
+                 :database (meta/id)
+                 :stages [{:lib/type :mbql.stage/mbql
+                           :source-card (:id (lib.tu/mock-cards :orders))}]}
+          product-table (meta/table-metadata :products)
+          [_ orders-product-id] (lib/join-condition-lhs-columns query product-table nil nil)
+          [products-id] (lib/join-condition-rhs-columns query product-table orders-product-id nil)]
+      (is (=? {:stages [{:joins [{:stages [{:source-table (:id product-table)}]}]}]}
+              (lib/join query (lib/join-clause product-table [(lib/= orders-product-id products-id)])))))))
 
 (deftest ^:parallel join-saved-question-test
   (is (=? {:lib/type :mbql/query

test/metabase/lib/test_metadata.cljc

@@ -123,7 +123,8 @@
   {:arglists '([table-name])}
   keyword)
 
-(defmulti ^:private field-metadata-method
+(defmulti field-metadata-method
+  "Metadata for fields"
   {:arglists '([table-name field-name])}
   (fn [table-name field-name]
     [(keyword table-name) (keyword field-name)]))

test/metabase/lib/test_util.cljc

@@ -261,3 +261,31 @@
    meta/metadata-provider
    (mock-metadata-provider
     {:cards [categories-native-card]})))
+
+(def mock-cards
+  "Map of mock MBQL query Card against the test tables."
+  (into {}
+        (for [[idx table] (m/indexed [:categories
+                                      :checkins
+                                      :users
+                                      :venues
+                                      :products
+                                      :orders
+                                      :people
+                                      :reviews])]
+          [table {:lib/type :metadata/card
+                  :id idx
+                  :name (str "Mock " (name table) " card")
+                  :dataset-query {:database (meta/id)
+                                  :type :query
+                                  :query {:source-table (meta/id table)}}
+                  :result-metadata (for [[[meta-table meta-col] _] (methods meta/field-metadata-method)
+                                         :when (= table meta-table)]
+                                     (dissoc (meta/field-metadata table meta-col) :id :table-id))}])))
+
+(def metadata-provider-with-mock-cards
+  "A metadata provider with all of the [[mock-cards]]. Composed with the normal [[meta/metadata-provider]]."
+  (lib.metadata.composed-provider/composed-metadata-provider
+    meta/metadata-provider
+    (mock-metadata-provider
+      {:cards (vals mock-cards)})))