Refactor conditional method invocation to more robust approach (#175)

Author: borkdude

.github/workflows/ci.yml

@@ -45,6 +45,14 @@ jobs:
         java -version
         bb --version
 
+    - name: 🔧 Install bb from dev build (until next release)
+      shell: bash
+      run: |
+        curl -sLO https://raw.githubusercontent.com/babashka/babashka/master/install
+        chmod +x ./install
+        ./install --dev-build --dir /tmp
+        cp /tmp/bb "$(which bb)"
+
     - name: Run bb tests
       run: |
         bb test:bb

deps.edn

@@ -1,4 +1,5 @@
 {:deps {babashka/fs {:mvn/version "0.4.18"}}
+ :paths ["src" "resources"]
  :aliases {:test {:extra-paths ["test"]
                   :extra-deps {io.github.cognitect-labs/test-runner {:git/tag "v0.5.1" :git/sha "dfb30dd"}}
                   :main-opts ["-m" "cognitect.test-runner"]}

project.clj

@@ -7,6 +7,7 @@
             :url "https://www.eclipse.org/legal/epl-1.0/"}
   :dependencies [[org.clojure/clojure "1.9.0"]
                  [babashka/fs "0.4.18"]]
+  :source-paths ["src" "resources"]
   :deploy-repositories [["clojars" {:url "https://clojars.org/repo"
                                     :username :env/clojars_user
                                     :password :env/clojars_pass

resources/META-INF/native-image/babashka/process/reflect-config.json

@@ -0,0 +1,4 @@
+[ {
+  "name" : "org.graalvm.nativeimage.ProcessProperties",
+  "methods": [{"name": "exec"}]
+} ]

src/babashka/process.cljc

@@ -604,16 +604,10 @@
                      :err :string} opts)]
     @(process* {:cmd cmd :opts opts :prev prev})))
 
-(def ^:private has-exec?
-  (boolean (try (.getMethod ^Class
-                 (resolve 'org.graalvm.nativeimage.ProcessProperties) "exec"
-                            (into-array [java.nio.file.Path (Class/forName "[Ljava.lang.String;") java.util.Map]))
-                (catch Exception _ false))))
-
-(defmacro ^:no-doc
-  if-has-exec [then else]
-  (if has-exec?
-    then else))
+(def ^:private exec-meth
+  (delay (try (.getMethod (Class/forName "org.graalvm.nativeimage.ProcessProperties") "exec"
+                          (into-array [java.nio.file.Path (Class/forName "[Ljava.lang.String;") java.util.Map]))
+              (catch Exception _ nil))))
 
 (defn exec
   "Replaces the current process image with the process image specified
@@ -649,10 +643,10 @@
           ^java.util.Map env (into (or (as-string-map env)
                                        (into {} (System/getenv)))
                                    (as-string-map extra-env))]
-      (if-has-exec
-       (org.graalvm.nativeimage.ProcessProperties/exec (fs/path program)
-                                                       (into-array String args)
-                                                       env)
+      (if-let [^java.lang.reflect.Method meth @exec-meth]
+        (.invoke meth nil (into-array Object [(fs/path program)
+                                              (into-array String args)
+                                              env]))
        (throw (ex-info "exec is not supported in non-GraalVM environments" {:cmd cmd}))))))
 
 (def ^:private default-shell-opts