From 2e3fa98e5be9799892f2340ca166f36ef913cc4b Mon Sep 17 00:00:00 2001
From: Peter Taoussanis <peter@taoensso.com>
Date: Tue, 13 Dec 2022 10:36:10 +0100
Subject: [PATCH] [fix] [#12] Fix issue with duplicate side effects when using
 within another macro

---
 src/taoensso/truss/impl.cljc   |  8 ++++++--
 test/taoensso/truss_tests.cljc | 26 +++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/taoensso/truss/impl.cljc b/src/taoensso/truss/impl.cljc
index b79bf7b..dfe4842 100644
--- a/src/taoensso/truss/impl.cljc
+++ b/src/taoensso/truss/impl.cljc
@@ -245,14 +245,18 @@
 
 (defn- ns-sym [] (symbol (str *ns*)))
 
+#?(:clj
+   (defn const-form? "See issue #12" [x]
+     (not (or (list? x) (instance? clojure.lang.Cons x)))))
+
 #?(:clj
    (defmacro -invar
      "Written to maximize performance + minimize post Closure+gzip Cljs code size."
      [elidable? truthy? line pred x ?data-fn]
-     (let [safe-x? (not (list? x)) ; Pre-evaluated (common case)
+     (let [const-x? (const-form? x) ; Common case
            [pred* safe-pred?] (xpred #?(:clj nil :cljs &env) pred)]
 
-       (if safe-x? ; Common case
+       (if const-x? ; Common case
          (if safe-pred? ; Common case
            `(if (~pred* ~x)
               ~(if truthy? true x)
diff --git a/test/taoensso/truss_tests.cljc b/test/taoensso/truss_tests.cljc
index b0e42db..a81959d 100644
--- a/test/taoensso/truss_tests.cljc
+++ b/test/taoensso/truss_tests.cljc
@@ -4,7 +4,10 @@
    [clojure.string  :as str]
    [taoensso.encore :as enc   :refer [throws throws?]]
    [taoensso.truss  :as truss :refer [have have? have! have!?]]
-   [taoensso.truss.impl :as impl]))
+   [taoensso.truss.impl :as impl])
+
+  #?(:cljs
+     (:require-macros [taoensso.truss-tests :refer [my-macro1]])))
 
 (comment
   (remove-ns      'taoensso.truss-tests)
@@ -125,4 +128,25 @@
 
 ;;;;
 
+#?(:clj (defmacro my-macro1 "See issue #12" [n x] `(have string? (do (swap! ~n inc) ~x))))
+
+(deftest _side-effects
+  (testing "Side effects"
+
+    (let [n (atom 0)]
+      [(is (= (have string? (do (swap! n inc) "str")) "str"))
+       (is (= @n 1))])
+
+    (let [n (atom 0)]
+      [(is (throws? (have string? (do (swap! n inc) :kw))))
+       (is (= @n 1))])
+
+    (let [n (atom 0)]
+      [(is (= (my-macro1 n "str") "str"))
+       (is (= @n 1))])
+
+    (let [n (atom 0)]
+      [(is (throws? (my-macro1 n :kw)))
+       (is (= @n 1))])))
+
 #?(:cljs (test/run-tests))