[Fix #239] Teach clean-ns about more metadata

The performance hit in considering literally every piece of metadata
shouldn't be too detrimental so we'll just err on the side of caution
for now.

src/refactor_nrepl/find/symbols_in_file.clj

@@ -34,6 +34,12 @@
               (.substring s 0 (dec (.length s)))
               s))))
 
+(defn- strip-meta-from-reader
+  [metadata]
+  (-> metadata
+      (dissoc :line :column :end-line :end-column)
+      not-empty))
+
 (defn symbols-in-file
   "Return a set of all the symbols occurring in the file at path.
 
@@ -63,24 +69,33 @@
          (let [rdr (-> path slurp core/file-content-sans-ns
                        readers/indexing-push-back-reader)
                rdr-opts {:read-cond :allow :features #{dialect} :eof :eof}
-               syms (atom #{})
-               collect-symbol (fn [form]
-                                ;; Regular symbol
-                                (when (symbol? form)
-                                  (swap! syms conj (normalize-ctor-call form)))
-                                ;; Classes used in typehints
-                                (when-let [t (:tag (meta form))]
-                                  (swap! syms conj t))
-                                (when (and (keyword? form)
-                                           (core/fully-qualified? form))
-                                  (swap! syms conj
-                                         (symbol (core/prefix form)
-                                                 (core/suffix form))))
-                                form)]
-           (loop [form (reader/read rdr-opts rdr)]
-             (when (not= form :eof)
-               (walk/prewalk collect-symbol form)
-               (recur (reader/read rdr-opts rdr))))
-           (->> @syms
-                (map (partial fix-ns-of-backquoted-symbols (dialect parsed-ns)))
-                set)))))))
+               syms (atom #{})]
+           (letfn [(collect-symbols [form]
+                     (let [minimal-meta (strip-meta-from-reader (meta form))]
+                       ;; metadata used in metadata-based protocol extensions
+                       ;; see #239 for an example
+                       (when minimal-meta
+                         (->> minimal-meta
+                              seq
+                              flatten
+                              (run! collect-symbols)))
+                       ;; Regular symbol
+                       (when (symbol? form)
+                         (swap! syms conj (normalize-ctor-call form)))
+                       ;; Classes used in typehints
+                       (when-let [t (:tag minimal-meta)]
+                         (swap! syms conj t))
+                       (when (and (keyword? form)
+                                  (core/fully-qualified? form))
+                         (swap! syms conj
+                                (symbol (core/prefix form)
+                                        (core/suffix form)))))
+                     form)]
+             (loop [form (reader/read rdr-opts rdr)]
+               (when (not= form :eof)
+                 (walk/prewalk collect-symbols form)
+                 (recur (reader/read rdr-opts rdr))))
+             (->> @syms
+                  (map
+                   (partial fix-ns-of-backquoted-symbols (dialect parsed-ns)))
+                  set))))))))

src/refactor_nrepl/ns/clean_ns.clj

@@ -43,10 +43,11 @@
     (assert (core/source-file? path))
     ;; Prefix notation not supported in cljs.
     ;; We also turn it off for cljc for reasons of symmetry
-    (config/with-config {:prefix-rewriting (if (or (core/cljs-file? path)
-                                                   (core/cljc-file? path))
-                                             false
-                                             (:prefix-rewriting config/*config*))}
+    (config/with-config {:prefix-rewriting
+                         (if (or (core/cljs-file? path)
+                                 (core/cljc-file? path))
+                           false
+                           (:prefix-rewriting config/*config*))}
       (let [ns-form (validate (core/read-ns-form-with-meta path))
             deps-preprocessor (if (get config/*config* :prune-ns-form)
                                 #(prune-dependencies % path)

test/refactor_nrepl/ns/clean_ns_test.clj

@@ -235,9 +235,10 @@
     (is (= expected actual))))
 
 (deftest preserves-all-meta
-  (let [actual (pprint-ns (clean-ns ns-with-lots-of-meta))
-        expected (slurp (:path ns-with-lots-of-meta-clean))]
-    (is (= expected actual))))
+  (config/with-config {:prefix-rewriting false}
+    (let [actual (pprint-ns (clean-ns ns-with-lots-of-meta))
+          expected (slurp (:path ns-with-lots-of-meta-clean))]
+      (is (= expected actual)))))
 
 (deftest does-not-remove-dollar-sign-if-valid-symbol
   (let [cleaned (pprint-ns (clean-ns ns-using-dollar))]

test/resources/ns_with_lots_of_meta.clj

@@ -1,12 +1,19 @@
-(ns ^:md1 ^:md2 ^{:longhand "as well" :really? "yes" :ok true} ns-with-gen-class-methods-meta
+(ns ^:md1 ^:md2 ^{:longhand "as well" :really? "yes" :ok true}
+ ns-with-gen-class-methods-meta
   (:gen-class
    :methods [^:static [foo [String] String]
              ^{:test true} [bar [String] String]
              ^{:other "text"} [baz [String] String]]
    :name Name)
-  (:require [clojure.string :as s]
-            [clojure.pprint :refer [fresh-line]]))
+  (:require
+   [clojure.string :as s]
+   [clojure.pprint :refer [fresh-line]]
+   [clojure.edn :as edn]))
 
 (defn useit
   []
   (fresh-line))
+
+(defn issue-239-metadata-based-protocol-extension []
+  ;; https://github.com/clojure-emacs/refactor-nrepl/issues/239
+  ^{`s/whatever-goes true} {})

test/resources/ns_with_lots_of_meta_clean.clj

@@ -7,4 +7,5 @@
              ^{:other "text"} [baz [String] String]]
    :name Name)
   (:require
-   [clojure.pprint :refer [fresh-line]]))
+   [clojure.pprint :refer [fresh-line]]
+   [clojure.string :as s]))