Support watching several shadow-cljs builds.

Add a cider-shadow-watched-builds customization variable which is the list of
builds to watch. If not defined fallback on watching the default build set in
cider-shadow-default-options or prompt the user.

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New features
 
 * [#2909](https://github.com/clojure-emacs/cider/issues/2909): Add new customization variable `cider-inspector-auto-select-buffer` to control the auto selection of the inspector buffer.
+* Add a new customization variable cider-shadow-watched-builds to allow watching several shadow-cljs builds at the same time.
 
 ### Bugs fixed
 

cider.el

@@ -719,6 +719,11 @@ Generally you should not disable this unless you run into some faulty check."
       options
     (concat ":" options)))
 
+(defcustom cider-shadow-watched-builds nil
+  "Defines the list of builds `shadow-cljs' should watch."
+  :type '(repeat string)
+  :package-version '(cider . "0.26.2"))
+
 (defcustom cider-shadow-default-options nil
   "Defines default `shadow-cljs' options."
   :type 'string
@@ -758,17 +763,26 @@ not just a string."
 We have to prompt the user to select a build, that's why
 this is a command, not just a string."
   (let* ((shadow-require "(require '[shadow.cljs.devtools.api :as shadow])")
+
+         (default-build (cider-normalize-cljs-init-options
+                         (or cider-shadow-default-options
+                             (car cider-shadow-watched-builds)
+                             (completing-read "Select shadow-cljs build: "
+                                              (cider--shadow-get-builds)))))
+
+         (watched-builds (or (mapcar #'cider-normalize-cljs-init-options cider-shadow-watched-builds)
+                             (list default-build)))
+
+         (watched-builds-form (mapconcat (lambda (build) (format "(shadow/watch %s)" build))
+                                         watched-builds
+                                         " "))
          ;; form used for user-defined builds
-         (user-build-form "(do %s (shadow/watch %s) (shadow/nrepl-select %s))")
+         (user-build-form "(do %s %s (shadow/nrepl-select %s))")
          ;; form used for built-in builds like :browser-repl and :node-repl
-         (default-build-form "(do %s (shadow/%s))")
-         (options (or cider-shadow-default-options
-                      (completing-read "Select shadow-cljs build: "
-                                       (cider--shadow-get-builds))))
-         (build (cider-normalize-cljs-init-options options)))
-    (if (member build '(":browser-repl" ":node-repl"))
-        (format default-build-form shadow-require (string-remove-prefix ":" build))
-      (format user-build-form shadow-require build build))))
+         (default-build-form "(do %s (shadow/%s))"))
+    (if (member default-build '(":browser-repl" ":node-repl"))
+        (format default-build-form shadow-require (string-remove-prefix ":" default-build))
+      (format user-build-form shadow-require watched-builds-form default-build))))
 
 (defcustom cider-figwheel-main-default-options nil
   "Defines the `figwheel.main/start' options.

doc/modules/ROOT/pages/cljs/shadow-cljs.adoc

@@ -44,7 +44,8 @@ root of your project.
 [source,clojure]
 ----
 ((nil . ((cider-default-cljs-repl . shadow)
-         (cider-shadow-default-options . "<your-build-name-here>"))))
+         (cider-shadow-default-options . "<your-build-name-here>")
+         (cider-shadow-watched-builds . ("<first-build>" "<other-build>")))))
 ----
 
 === Using cider-connect-cljs