Make cider-repl-set-ns more reliable on Piggieback connections

Fixes #3503
Partially reverts 5f705b

CHANGELOG.md

@@ -37,8 +37,9 @@
 - [#3250](https://github.com/clojure-emacs/cider/issues/3250): Don't lose the CIDER session over TRAMP files.
 - [#3413](https://github.com/clojure-emacs/cider/issues/3413): Make jump-to-definition work in projects needing `cider-path-translations` (i.e. Dockerized projects).
 - [#2436](https://github.com/clojure-emacs/cider/issues/2436): Prevent malformed `cider-repl-history-file`s from failing `cider-jack-in`.
-- [#3456](https://github.com/clojure-emacs/cider/issues/3456): restore xref-based jump-to-definition in Babashka (and any nREPL clients not having cider-nrepl).
+- [#3456](https://github.com/clojure-emacs/cider/issues/3456): Restore xref-based jump-to-definition in Babashka (and any nREPL clients not having cider-nrepl).
 - [#3466](https://github.com/clojure-emacs/cider/issues/3466): Restore usual `cider--connected-handler` performance for JVM Clojure repls.
+- [#3503](https://github.com/clojure-emacs/cider/issues/3503): Make `cider-repl-set-ns` more reliable on Piggieback connections.
 - Fix the `xref-find-definitions` CIDER backend to return correct filenames.
 - Fix the `cider-xref-fn-deps` buttons to direct to the right file.
 - Fix the `cider-find-keyword` overall reliability and correctness, particularly for ClojureScript.

cider-repl.el

@@ -1321,8 +1321,15 @@ command will prompt for the name of the namespace to switch to."
       ;; That's why we eval them separately instead of combining them with `do'.
       (when cider-repl-require-ns-on-set
         (cider-sync-tooling-eval (format "(require '%s)" ns) nil connection))
-      (cider-tooling-eval (format "(in-ns '%s)" ns)
-                          (cider-repl-switch-ns-handler connection)))))
+      (let ((f (if (equal 'cljs
+                          (with-current-buffer connection
+                            cider-repl-type))
+                   ;; For cljs, don't use cider-sync-tooling-eval, because Piggieback will later change the ns (issue #3503):
+                   #'cider-nrepl-request:eval
+                 ;; When possible, favor cider-sync-tooling-eval because it preserves *1, etc (commit 5f705b):
+                 #'cider-sync-tooling-eval)))
+        (funcall f (format "(in-ns '%s)" ns)
+                 (cider-repl-switch-ns-handler connection))))))
 
 
 ;;; Location References