[GR-52676] Handle the Panama Truffle NFI backend not being available …

…when embedded

* We cannot just add it as a dependency of TruffleRuby because
  the Panama backend is 22+ but Truffle 24.2 will still support JDK 21.
  We can add it as a dependency once Truffle drops supports for JDK 21.

lib/truffle/truffle/cext.rb

@@ -190,7 +190,20 @@ def self.init_libtrufflerubytrampoline(libtrampoline)
 
     init_functions = libtrampoline[:rb_tr_trampoline_init_functions]
     init_functions = Primitive.interop_eval_nfi('(env,(string):pointer):void').bind(init_functions)
-    if Truffle::Boot.get_option 'cexts-panama' and Primitive.vm_java_version >= 22 and !TruffleRuby.native?
+
+    panama = Truffle::Boot.get_option('cexts-panama') && Primitive.vm_java_version >= 22 && !TruffleRuby.native?
+    if panama
+      # Check if the Panama backend is available, it might not be when embedding TruffleRuby
+      rb_tr_invoke = LIBTRUFFLERUBY['rb_tr_invoke']
+      begin
+        keep_alive << rb_tr_invoke.createNativeClosure('panama')
+      rescue Polyglot::ForeignException => e
+        warn "warning: the Panama Truffle NFI backend for running C extensions faster was not available (#{e.message}). Add 'org.graalvm.truffle:truffle-nfi-panama' to Maven dependencies to resolve that."
+        panama = false
+      end
+    end
+
+    if panama
       init_functions.call(-> name {
         closure = LIBTRUFFLERUBY[name].createNativeClosure('panama')
         keep_alive << closure

src/test-embedding/java/org/truffleruby/test/embedding/ContextPermissionsTest.java

@@ -77,6 +77,13 @@ public void testRequireGem() {
         }
     }
 
+    @Test
+    public void testRequireCExtension() {
+        try (Context context = Context.newBuilder("ruby").allowIO(IOAccess.ALL).allowNativeAccess(true).build()) {
+            Assert.assertEquals("Etc", context.eval("ruby", "require 'etc'; Etc.to_s").asString());
+        }
+    }
+
     @Test
     public void testThreadsNoNative() throws Throwable {
         // The ruby.single_threaded option needs to be set because --single-threaded defaults to --embedded.