Fix #906: merge-opts loses :features of previous context (#921)

CHANGELOG.md

@@ -14,6 +14,7 @@ SCI is used in [babashka](https://github.com/babashka/babashka),
 
 - Fix [#626](https://github.com/babashka/sci/issues/626): add `cljs.core/exists?`
 - Fix [#919](https://github.com/babashka/sci/issues/919): :js-libs + refer + rename clashes with core var
+- Fix [#906](https://github.com/babashka/sci/issues/906): `merge-opts` loses `:features` or previous context
 
 ## 0.8.41 (2023-11-24)
 

src/sci/impl/opts.cljc

@@ -213,7 +213,8 @@
                 #?(:cljs :js-libs)
                 :ns-aliases]
          :or {load-fn (:load-fn env)
-              #?@(:cljs [async-load-fn (:async-load-fn env)])}} opts
+              #?@(:cljs [async-load-fn (:async-load-fn env)])
+              features (:features ctx)}} opts
         raw-classes (merge (:raw-classes @!env) classes)
         classes (normalize-classes raw-classes)
         _ (init-env! !env bindings aliases namespaces classes raw-classes imports load-fn #?(:cljs async-load-fn) #?(:cljs js-libs) ns-aliases)

test/sci/core_test.cljc

@@ -1428,6 +1428,11 @@
     (swap! C sci/merge-opts {:namespaces {'n {'foo 2}}})
     (is (= 2 (sci/eval-form @C 'n/foo)))))
 
+(deftest merge-opts-preserves-features-test
+  (let [ctx(sci/init {:features #{:cljs}})]
+    (is (= 2 (sci/eval-string* ctx "#?(:clj 1 :cljs 2)")))
+    (is (= 2 (sci/eval-string* (sci/merge-opts ctx {}) "#?(:clj 1 :cljs 2)")))))
+
 (deftest dynamic-meta-def-test
   (is (= false (eval* "(def ^{:private (if (odd? 1) false true)} foo) (:private (meta #'foo))")))
   (is (= "6" (eval* "(def ^{:doc (str (+ 1 2 3))} foo) (:doc (meta #'foo))")))