Fingerprinting: correctly handle datetimes that are also FKs (#10621)

src/metabase/sync/analyze/fingerprint/fingerprinters.clj

@@ -85,6 +85,7 @@
 (prefer-method fingerprinter [:type/* :type/PK] [:type/Number :type/*])
 (prefer-method fingerprinter [:type/* :type/PK] [:type/Text :type/*])
 (prefer-method fingerprinter [:type/DateTime :type/*] [:type/* :type/PK])
+(prefer-method fingerprinter [:type/DateTime :type/*] [:type/* :type/FK])
 
 (defn- with-global-fingerprinter
   [fingerprinter]

test/metabase/sync/analyze/fingerprint/fingerprinters_test.clj

@@ -13,6 +13,17 @@
              (fingerprinter (field/map->FieldInstance {:base_type :type/DateTime}))
              [#inst "2013" #inst "2018" #inst "2015"]))
 
+;; Correctly disambiguate multiple competing multimethods
+(expect
+  {:global {:distinct-count 3
+            :nil%           0.0}
+   :type {:type/DateTime {:earliest (du/date->iso-8601 #inst "2013")
+                          :latest   (du/date->iso-8601 #inst "2018")}}}
+  (transduce identity
+             (fingerprinter (field/map->FieldInstance {:base_type    :type/DateTime
+                                                       :special_type :type/FK}))
+             [#inst "2013" #inst "2018" #inst "2015"]))
+
 (expect
   {:global {:distinct-count 1
             :nil%           1.0}