Description:
------------
The change to using `serialize_precision` in `json_encode()` may have had some side affects. Floating point numbers under 1.0 get a different precision than other floating point numbers and the precision for those numbers can be unpredictable.

I noticed that `var_export()` is behaving the in the same way, but that is far less critical because it's not used as a data exchange format.


At the moment, I have a single workaround for a single case - When encoding a JSON object only dealing with the exact same precision values, setting `serialize_precision` to 2 gives the expected result. That won't work for objects with mixed precision though.

Test script:
---------------
<?php

# Getting the precision on the cli seems to change it.
# Before these two lines were added, I was getting 53 points of precision.
# After, it adhered to the value for serialize_precision and stayed there.
#print 'Precision is set to '.ini_get('precision').PHP_EOL;
#print 'Serialize Precision is set to '.ini_get('serialize_precision').PHP_EOL;

$data = array(
        0.35,
        (float)0.35,
        round(0.35, 2),
        0.15,
        1.25,
        1.23,
        1.0,
        0.9,
        4,
);

print 'var_export: '.PHP_EOL.var_export($data, 1).PHP_EOL;

print 'json_encode: '.PHP_EOL.json_encode($data, JSON_PRESERVE_ZERO_FRACTION).PHP_EOL;

print 'print_r'.PHP_EOL;

print_r($data);



Expected result:
----------------
var_export:
array (
  0 => 0.35,
  1 => 0.35,
  2 => 0.35,
  3 => 0.15,
  4 => 1.25,
  5 => 1.23,
  6 => 1.0,
  7 => 0.9,
  8 => 4,
)
json_encode:
[0.35,0.35,0.35,0.15,1.25,1.23,1.0,0.9,4]
print_r
Array
(
    [0] => 0.35
    [1] => 0.35
    [2] => 0.35
    [3] => 0.15
    [4] => 1.25
    [5] => 1.23
    [6] => 1
    [7] => 0.9
    [8] => 4
)

Actual result:
--------------
var_export:
array (
  0 => 0.34999999999999997779553950749686919152736663818359375,
  1 => 0.34999999999999997779553950749686919152736663818359375,
  2 => 0.34999999999999997779553950749686919152736663818359375,
  3 => 0.1499999999999999944488848768742172978818416595458984375,
  4 => 1.25,
  5 => 1.229999999999999982236431605997495353221893310546875,
  6 => 1.0,
  7 => 0.90000000000000002220446049250313080847263336181640625,
  8 => 4,
)
json_encode:
[0.34999999999999997779553950749686919152736663818359375,0.34999999999999997779553950749686919152736663818359375,0.34999999999999997779553950749686919152736663818359375,0.1499999999999999944488848768742172978818416595458984375,1.25,1.229999999999999982236431605997495353221893310546875,1.0,0.90000000000000002220446049250313080847263336181640625,4]
print_r
Array
(
    [0] => 0.35
    [1] => 0.35
    [2] => 0.35
    [3] => 0.15
    [4] => 1.25
    [5] => 1.23
    [6] => 1
    [7] => 0.9
    [8] => 4
)