Merge pull request #3481 from takluyver/rmagic-nicer-errors

Display R errors without Python traceback

IPython/extensions/rmagic.py

@@ -578,6 +578,7 b' class RMagics(Magics):'
         self.r('png("%s/Rplots%%03d.png",%s)' % (tmpd.replace('\\', '/'), png_args))
 
         text_output = ''
+        try:
         if line_mode:
             for line in code.split(';'):
                 text_result, result = self.eval(line)
@@ -589,6 +590,13 b' class RMagics(Magics):'
             text_result, result = self.eval(code)
             text_output += text_result
 
+        except RInterpreterError as e:
+            print(e.stdout)
+            if not e.stdout.endswith(e.err):
+                print(e.err)
+            rmtree(tmpd)
+            return
+
         self.r('dev.off()')
 
         # read out all the saved .png files