Allow multiple key-value pairs for assoc-default (#31130)

src/metabase/util.cljc

@@ -787,8 +787,17 @@
 
 (defn assoc-default
   "Called like `(assoc m k v)`, this does [[assoc]] iff `m` does not contain `k`
-  and `v` is not nil."
-  [m k v]
-  (if (or (nil? v) (contains? m k))
-    m
-    (assoc m k v)))
+  and `v` is not nil. Can be called with multiple key value pairs. If a key occurs
+  more than once, only the first occurrence with a non-nil value is used."
+  ([m k v]
+   (if (or (nil? v) (contains? m k))
+     m
+     (assoc m k v)))
+  ([m k v & kvs]
+    (let [ret (assoc-default m k v)]
+      (if kvs
+        (if (next kvs)
+          (recur ret (first kvs) (second kvs) (nnext kvs))
+          (throw (ex-info "assoc-default expects an even number of key-values"
+                          {:kvs kvs})))
+        ret))))

test/metabase/util_test.cljc

@@ -391,3 +391,23 @@
     (is (= {:foo false}
            (u/assoc-dissoc {:foo "bar"} :foo false))
         "false should be assoc'd")))
+
+(deftest ^:parallel assoc-default-test
+  (testing "nil map"
+    (is (= {:x 0}
+           (u/assoc-default nil :x 0))))
+  (testing "empty map"
+    (is (= {0 :x}
+           (u/assoc-default {} 0 :x))))
+  (testing "existing key"
+    (is (= {:x 0}
+           (u/assoc-default {:x 0} :x 1))))
+  (testing "nil value"
+    (is (= {:x 0}
+           (u/assoc-default {:x 0} :y nil))))
+  (testing "multiple defaults"
+    (is (= {:x nil, :z 1}
+           (u/assoc-default {:x nil} :x 0 :y nil :z 1))))
+  (testing "multiple defaults for the same key"
+    (is (= {:x nil, :y 1, :z 2}
+           (u/assoc-default {:x nil} :x 0, :y nil, :y 1, :z 2, :x 3, :z 4)))))