[fix] [#21] Work around issue with use in Cljs core.async/go bodies

Problem:
  (clojure.core.async/go (taoensso.telemere/log! "hello")) ; Compiles fine
  (cljs.core.async/go    (taoensso.telemere/log! "hello")) ; Compile fails

I could try to get to the bottom of exactly what's going on - but ultimately
IOC mechanisms like `go` are always going to be a bit fragile, especially for
heavily-optimized/unusual code.

In this case, the problem is thankfully only with Cljs - and Telemere's Cljs
performance isn't too critical - so I think we can afford to just bypass any
potential fiddling by the `go` macro by wrapping Cljs Telemere expansions in
an IIFE ((fn [] ...)).

Downside is the (small) added cost of a function construction and call.
Upside   is avoiding potential issues with core.async and other similar
IOC-style systems (Electric Clojure, etc.)

projects/main/project.clj

@@ -46,7 +46,8 @@
      *unchecked-math*     false #_:warn-on-boxed}
 
     :dependencies
-    [[org.clojure/test.check             "1.1.1"]
+    [[org.clojure/core.async           "1.6.681"]
+     [org.clojure/test.check             "1.1.1"]
      [org.clojure/tools.logging          "1.3.0"]
      [org.slf4j/slf4j-api               "2.0.16"]
      [com.taoensso/telemere-shell "1.0.0-SNAPSHOT"]

projects/main/src/taoensso/telemere/impl.cljc

@@ -687,6 +687,13 @@
                         (sig-middleware# signal#) ; Apply signal middleware, can throw
                         (do              signal#)))))
 
+               ;; Could avoid double `run-form` expansion with a fn wrap (>0 cost)
+               ;; (let [run-fn-form (when run-form `(fn [] (~run-form)))]
+               ;;   `(let [~'run-fn-form ~run-fn-form]
+               ;;      (if-not ~allow?
+               ;;        (run-fn-form)
+               ;;        (let [...]))))
+
                into-let-form
                (enc/cond!
                  (not trace?) ; Don't trace
@@ -734,39 +741,37 @@
                            (enc/try*
                              (do            (RunResult. ~run-form nil (- (enc/now-nano*) t0#)))
                              (catch :all t# (RunResult. nil       t#  (- (enc/now-nano*) t0#)))
-                             (finally (.close otel-scope#))))))])]
-
-           ;; Could avoid double `run-form` expansion with a fn wrap (>0 cost)
-           ;; (let [run-fn-form (when run-form `(fn [] (~run-form)))]
-           ;;   `(let [~'run-fn-form ~run-fn-form]
-           ;;      (if-not ~allow?
-           ;;        (run-fn-form)
-           ;;        (let [...]))))
-
-           ;; Unless otherwise specified, allow errors to throw on call
-           `(let [~'__kind  ~kind-form
-                  ~'__ns    ~ns-form
-                  ~'__id    ~id-form
-                  ~'__level ~level-form]
-
-              (enc/if-not ~allow?
-                ~run-form
-                (let [~'__inst   ~inst-form
-                      ~'__thread ~thread-form
-                      ~'__root0  ~root-form0 ; ?{:keys [id uid]}
-
-                      ~@into-let-form ; Inject conditional bindings
-                      signal# ~signal-delay-form]
-
-                  (dispatch-signal!
-                    ;; Unconditionally send same wrapped signal to all handlers.
-                    ;; Each handler will use wrapper for handler filtering,
-                    ;; unwrapping (realizing) only allowed signals.
-                    (WrappedSignal. ~'__ns ~'__kind ~'__id ~'__level signal#))
-
-                  (if ~'__run-result
-                    ( ~'__run-result signal#)
-                    true)))))))))
+                             (finally (.close otel-scope#))))))])
+
+               final-form
+               ;; Unless otherwise specified, allow errors to throw on call
+               `(let [~'__kind  ~kind-form
+                      ~'__ns    ~ns-form
+                      ~'__id    ~id-form
+                      ~'__level ~level-form]
+
+                  (enc/if-not ~allow?
+                    ~run-form
+                    (let [~'__inst   ~inst-form
+                          ~'__thread ~thread-form
+                          ~'__root0  ~root-form0 ; ?{:keys [id uid]}
+
+                          ~@into-let-form ; Inject conditional bindings
+                          signal# ~signal-delay-form]
+
+                      (dispatch-signal!
+                        ;; Unconditionally send same wrapped signal to all handlers.
+                        ;; Each handler will use wrapper for handler filtering,
+                        ;; unwrapping (realizing) only allowed signals.
+                        (WrappedSignal. ~'__ns ~'__kind ~'__id ~'__level signal#))
+
+                      (if ~'__run-result
+                        ( ~'__run-result signal#)
+                        true))))]
+
+           (if cljs?
+             `((fn [] ~final-form)) ; IIFE wrap for use in `go` and other IOC-style bodies
+             (do       final-form)))))))
 
 (comment
   (with-signal  (signal! {:level :warn :let [x :x] :msg ["Test" "message" x] :data {:a :A :x x} :run (+ 1 2)}))

projects/main/test/taoensso/telemere_tests.cljc

@@ -1,6 +1,7 @@
 (ns taoensso.telemere-tests
   (:require
    [clojure.test            :as test :refer [deftest testing is]]
+   [clojure.core.async      :as async]
    [taoensso.encore         :as enc  :refer [throws? submap?] :rename {submap? sm?}]
    [taoensso.encore.signals :as sigs]
    [taoensso.telemere       :as tel]
@@ -658,6 +659,12 @@
            ;;
            (do (enc/set-var-root! impl/*sig-handlers* nil) :unset-handler)])))])
 
+;;;;
+
+(deftest _core-async
+  (testing "Signals in go macros"
+    [(async/go (tel/log! "hello"))]))
+
 ;;;; Interop
 
 (comment (def ^org.slf4j.Logger sl (org.slf4j.LoggerFactory/getLogger "my.class")))