Render CSV append errors as markdown (#39651)

src/metabase/upload.clj

@@ -579,6 +579,19 @@
     :type/Date                   ::date
     :type/Text                   ::text))
 
+(defn- not-blank [s]
+  (when-not (str/blank? s)
+    s))
+
+(defn- extra-and-missing-error-markdown [extra missing]
+  (->> [[(tru "The CSV file contains extra columns that are not in the table:") extra]
+        [(tru "The CSV file is missing columns that are in the table:") missing]]
+       (keep (fn [[header columns]]
+               (when (seq columns)
+                 (str/join "\n" (cons header (map #(str "- " %) columns))))))
+       (str/join "\n\n")
+       (not-blank)))
+
 (defn- check-schema
   "Throws an exception if:
     - the CSV file contains duplicate column names
@@ -593,18 +606,7 @@
       (throw (ex-info (tru "The CSV file contains duplicate column names.")
                       {:status-code 422})))
     (when (or extra missing)
-      (let [format-columns (fn [cols]
-                             (str/join ", " (map #(str "\"" % "\"") cols)))
-            error-message (cond
-                            (and extra missing)
-                            (tru "The CSV file contains extra columns that are not in the table: {0}. The CSV file is missing columns that are in the table: {1}."
-                                 (format-columns extra) (format-columns missing))
-                            extra
-                            (tru "The CSV file contains extra columns that are not in the table: {0}."
-                                 (format-columns extra))
-                            missing
-                            (tru "The CSV file is missing columns that are in the table: {0}."
-                                 (format-columns missing)))]
+      (let [error-message (extra-and-missing-error-markdown extra missing)]
         (throw (ex-info error-message {:status-code 422}))))))
 
 (defn- append-csv!*

test/metabase/upload_test.clj

@@ -1282,7 +1282,7 @@
               :data    {:status-code 422}}
              (catch-ex-info (append-csv-with-defaults! :is-upload false)))))
     (testing "The CSV file must not be empty"
-      (is (= {:message "The CSV file is missing columns that are in the table: \"name\".",
+      (is (= {:message "The CSV file is missing columns that are in the table:\n- name",
               :data    {:status-code 422}}
              (catch-ex-info (append-csv-with-defaults! :file (csv-file-with [] (mt/random-name)))))))
     (testing "Uploads must be supported"
@@ -1313,19 +1313,34 @@
                      (rows-for-table table))))
             (io/delete-file file)))))))
 
+(defn- trim-lines [s]
+  (->> (str/split-lines s)
+       (map str/trim)
+       (str/join "\n")))
+
 (deftest append-column-mismatch-test
   (mt/test-drivers (mt/normal-drivers-with-feature :uploads)
     (with-uploads-allowed
       (testing "Append should fail if there are extra or missing columns in the CSV file"
         (doseq [[csv-rows error-message]
                 {["_mb_row_id,id,name,extra column one,EXTRA COLUMN TWO"]
-                 "The CSV file contains extra columns that are not in the table: \"extra_column_two\", \"extra_column_one\"."
+                 (trim-lines "The CSV file contains extra columns that are not in the table:
+                              - extra_column_two
+                              - extra_column_one")
 
                  [""]
-                 "The CSV file is missing columns that are in the table: \"id\", \"name\"."
+                 (trim-lines "The CSV file is missing columns that are in the table:
+                              - id
+                              - name")
 
                  ["_mb_row_id,extra 1, extra 2"]
-                 "The CSV file contains extra columns that are not in the table: \"extra_2\", \"extra_1\". The CSV file is missing columns that are in the table: \"id\", \"name\"."}]
+                 (trim-lines "The CSV file contains extra columns that are not in the table:
+                              - extra_2
+                              - extra_1
+
+                              The CSV file is missing columns that are in the table:
+                              - id
+                              - name")}]
           (with-upload-table!
             [table (create-upload-table!
                     {:col->upload-type (ordered-map/ordered-map