Errno.handle when getcwd fails in FeatureLoader, as if it was in Ruby

Author: chrisseaton

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -1088,6 +1088,10 @@ public DynamicObject getKernelModule() {
         return kernelModule;
     }
 
+    public DynamicObject getErrnoModule() {
+        return errnoModule;
+    }
+
     public GlobalVariables getGlobalVariables() {
         return globalVariables;
     }

src/main/java/org/truffleruby/language/loader/FeatureLoader.java

@@ -154,7 +154,7 @@ public String getWorkingDirectory() {
         final Pointer buffer = GetThreadBufferNode.getBuffer(context, bufferSize);
         final long address = nfi.asPointer((TruffleObject) getcwd.call(buffer.getAddress(), bufferSize));
         if (address == 0) {
-            throw new UnsupportedOperationException("getcwd() failed");
+            context.send(context.getCoreLibrary().getErrnoModule(), "handle");
         }
         final byte[] bytes = buffer.readZeroTerminatedByteArray(context, 0);
         final Encoding localeEncoding = context.getEncodingManager().getLocaleEncoding();