min and max should not return markers

Problem reported by Glenn Morris in:
http://lists.gnu.org/archive/html/emacs-devel/2017-03/msg00147.html
* src/data.c (minmax_driver): Convert any marker result to an
integer, since some callers assume this.
* test/src/data-tests.el (data-tests-max, data-tests-min):
Test for this.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/data.c b/src/data.c
index 29547d8a9ba..c480ed2068a 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2972,9 +2972,9 @@ minmax_driver (ptrdiff_t nargs, Lisp_Object *args,
       if (argnum == 0 || !NILP (arithcompare (val, accum, comparison)))
         accum = val;
       else if (FLOATP (accum) && isnan (XFLOAT_DATA (accum)))
-        break;
+        return accum;
     }
-  return accum;
+  return MARKERP (accum) ? make_number (marker_position (accum)) : accum;
 }
 
 DEFUN ("max", Fmax, Smax, 1, MANY, 0,