empty stub for os.fsync

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/PosixModuleBuiltins.java

@@ -2042,4 +2042,18 @@ PNone killFallback(VirtualFrame frame, Object pid, Object signal,
             return kill(frame, castInt.execute(pid), castInt.execute(signal), readSignalNode, isNode);
         }
     }
+
+    @Builtin(name = "fsync", minNumOfPositionalArgs = 1)
+    @GenerateNodeFactory
+    abstract static class FSyncNode extends PythonUnaryBuiltinNode {
+        @Specialization
+        PNone fsync(VirtualFrame frame, int fd) {
+            try {
+                getContext().getResources().fsync(fd);
+            } catch (ArrayIndexOutOfBoundsException e) {
+                throw raiseOSError(frame, OSErrorEnum.ENOENT.getNumber());
+            }
+            return PNone.NONE;
+        }
+    }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PosixResources.java

@@ -209,6 +209,10 @@ public int dup(int fd) {
         return dupFd;
     }
 
+    public void fsync(int fd) throws ArrayIndexOutOfBoundsException {
+        files.get(fd); // for the side-effect
+    }
+
     @TruffleBoundary(allowInlining = true)
     public int[] pipe() throws IOException {
         Pipe pipe = Pipe.open();