Fix %e handling of 0

Author: sparkprime

stdlib/std.jsonnet

@@ -543,7 +543,7 @@ limitations under the License.
 
     // Render floating point in scientific form
     local render_float_sci(n__, zero_pad, blank, sign, ensure_pt, trailing, caps, prec) =
-      local exponent = std.floor(std.log(std.abs(n__)) / std.log(10));
+      local exponent = if n__ == 0 then 0 else std.floor(std.log(std.abs(n__)) / std.log(10));
       local suff = (if caps then 'E' else 'e')
                    + render_int(exponent, 3, 0, false, true, 10, '');
       local mantissa = n__ / std.pow(10, exponent);

test_suite/format.jsonnet

@@ -134,7 +134,9 @@ std.assertEqual(std.format('thing-%#-8.4X', [910.3]), 'thing-0X038E  ') &&
 
 // e
 std.assertEqual(std.format('%e', [910]), '9.100000e+02') &&
+std.assertEqual(std.format('%e', [0]), '0.000000e+00') &&
 std.assertEqual(std.format('%.0le', [910]), '9e+02') &&
+std.assertEqual(std.format('%.0le', [0]), '0e+00') &&
 std.assertEqual(std.format('%#e', [-910]), '-9.100000e+02') &&
 std.assertEqual(std.format('%16e', [910]), '    9.100000e+02') &&
 std.assertEqual(std.format('%016e', [910]), '00009.100000e+02') &&