Don't prune cljsjs namespaces in clean-ns

These namespaces represent externs.  For now the exact symbols are
unknowable, so we can't determine if the ns is in use.  As a temporary
fix we just ignore these libspecs.  While I consider this a temp hack
it's unlikely to ever get improved on, unless someone else builds tooling
we can delegate to.

This fixes clojure-emacs/clj-refactor.el#275

CHANGELOG.md

@@ -13,17 +13,17 @@
 * Make `find-symbol` able to handle macros.
 
 ### Bugs fixed
-
-[clojure-emacs/clj-refactor.el#223](https://github.com/clojure-emacs/clj-refactor.el/issues/223) Fix clean-ns removing metadata when file starts with a comment.
-[#103](https://github.com/clojure-emacs/refactor-nrepl/issues/108) `find-symbol` failes in projects with `cljc` files.
-[#106](https://github.com/clojure-emacs/refactor-nrepl/issues/106) Failure to build ASTs when namespaced keywords are present in the project.
+* [clojure-emacs/clj-refactor.el#223](https://github.com/clojure-emacs/clj-refactor.el/issues/223) Fix clean-ns removing metadata when file starts with a comment.
+* [#103](https://github.com/clojure-emacs/refactor-nrepl/issues/108) `find-symbol` failes in projects with `cljc` files.
+* [#106](https://github.com/clojure-emacs/refactor-nrepl/issues/106) Failure to build ASTs when namespaced keywords are present in the project.
 
 ### Changes
 
+* [clojure-emacs/clj-refactor.el#275](https://github.com/clojure-emacs/clj-refactor.el/issues/275) clean-ns will no longer prune cljsjs requires.
 * New option for `clean-ns`, `prune-ns-form`, to avoid pruning the ns-form.
 * Get rid of the client namespace
 
-* [#118](https://github.com/clojure-emacs/refactor-nrepl/issues/118)Improve the `find-symbol` reply.  It's now a map instead of a
+* [#118](https://github.com/clojure-emacs/refactor-nrepl/issues/118) Improve the `find-symbol` reply.  It's now a map instead of a
   vector.
 * Remove `find-debug-fns`.  None of us ever used this and there's some
   overlap with `find-usages`.

src/refactor_nrepl/ns/prune_dependencies.clj

@@ -99,9 +99,8 @@
                 (= (:refer libspec) :all))
     (:refer libspec)))
 
-(defn- remove-unused-requires [symbols-in-file current-ns libspecs]
-  (map (partial remove-unused-syms-and-specs symbols-in-file current-ns)
-       libspecs))
+(defn- remove-unused-requires [symbols-in-file current-ns libspec]
+  (remove-unused-syms-and-specs symbols-in-file current-ns libspec))
 
 (defn- remove-unused-renamed-symbols
   [symbols-in-file {:keys [rename] :as libspec}]
@@ -111,11 +110,22 @@
                      :when (symbols-in-file (str alias))]
                  [sym alias]))))
 
+(defn- libspec-should-never-be-pruned? [libspec]
+  ;; The symbols of cljsjs namespaces are externs, and unknowable for now,
+  ;; so we just ignore these libspecs
+  (.startsWith (str (:ns libspec)) "cljsjs"))
+
+(defn- prune-libspec [symbols-in-file current-ns libspec]
+  (if (libspec-should-never-be-pruned? libspec)
+    libspec
+    (some->> libspec
+             (remove-unused-renamed-symbols symbols-in-file)
+             (remove-unused-requires symbols-in-file current-ns))))
+
 (defn- prune-libspecs
   [libspecs symbols-in-file current-ns]
   (->> libspecs
-       (map (partial remove-unused-renamed-symbols symbols-in-file))
-       (remove-unused-requires symbols-in-file current-ns)
+       (map (partial prune-libspec symbols-in-file current-ns))
        (filter (complement nil?))))
 
 (defn- prune-imports

test/resources/cljsns.cljs

@@ -1,6 +1,7 @@
 (ns resources.cljsns
   (:require [cljs.test :refer-macros [is deftest]]
             [cljs.test :refer-macros [is]]
+            [cljsjs.js-yaml] ; this one should not be pruned as it contains externs
             [clojure.string :refer [split-lines join]]
             [cljs.pprint :as pprint]
             [clojure.set :as set])
@@ -17,7 +18,7 @@
 
 (deftest tt
   (testing "whatever"
-      (is (= 1 1))))
+    (is (= 1 1))))
 
 (defn foo []
   `(join "foo bar"))

test/resources/cljsns_cleaned.cljs

@@ -1,6 +1,7 @@
 (ns resources.cljsns
   (:require [cljs.pprint :as pprint]
             [cljs.test :refer-macros [deftest is]]
+            cljsjs.js-yaml
             [clojure.set :as set]
             [clojure.string :refer [join split-lines]])
   (:require-macros cljs.analyzer.api