Ensure print-method for unreadable symbols preserves metadata

Author: mk

CHANGELOG.md

@@ -15,6 +15,7 @@ Changes can be:
 
 * 🔌 Make websocket reconnect automatically on close to avoid having to reload the page
 * 💫 Cache expressions that return `nil` in memory
+* 🐜 Ensure custom `print-method` supporting unreadable symbols preserves metadata
 
 ## 0.13.842 (2023-03-07)
 

src/nextjournal/clerk/viewer.cljc

@@ -343,7 +343,7 @@
 #?(:clj
    (defmethod print-method clojure.lang.Keyword [o w]
      (if (roundtrippable? o)
-       (.write w (str o))
+       (print-simple o w)
        (.write w (pr-str (->viewer-eval (if-let [ns (namespace o)]
                                           (list 'keyword ns (name o))
                                           (list 'keyword (name o)))))))))
@@ -352,7 +352,7 @@
    (defmethod print-method clojure.lang.Symbol [o w]
      (if (or (roundtrippable? o)
              (= (name o) "?@")) ;; splicing reader conditional, see issue #338
-       (.write w (str o))
+       (print-simple o w)
        (.write w (pr-str (->viewer-eval (if-let [ns (namespace o)]
                                           (list 'symbol ns (name o))
                                           (list 'symbol (name o)))))))))

test/nextjournal/clerk/viewer_test.clj

@@ -354,7 +354,11 @@
            (pr-str (symbol "~")))))
 
   (testing "splicing reader conditional prints normally (issue #338)"
-    (is (= "?@" (pr-str (symbol "?@"))))))
+    (is (= "?@" (pr-str (symbol "?@")))))
+
+  (testing "custom print-method for symbol preserves metadata"
+    (is (-> (binding [*print-meta* true]
+              (pr-str '[^:foo bar])) read-string first meta :foo))))
 
 (deftest removed-metadata
   (is (= "(do 'this)"