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From "Kevin R. Coombes" <>
Subject Re: [jira] [Commented] (COUCHDB-1407) JSON encoding of number changes
Date Mon, 13 Feb 2012 18:52:12 GMT
I've been staying out of the fray so far, but I want to (mostly) endorse 
Paul's summary and suggestion.  The hear tof my arguemnt is two simple 
[1] JSON only defines Number. It does not define separate integer and 
floating point numbers.
[2] CouchDB promises to respond to HTTP requests to PUT and GET data, 
and the return value is documented to be JSON.

These two points imply that CouchDB only knows about the kinds of data 
structures that JSON defines and supports, and thus can/should make no 
promises about the representation of  numbers beyond what you can get 
from JSON..

  If an application depends on the distinction between integers and 
floating point values, then it is up to the person writing the 
application to make sure this distinction survives.  As has already been 
pointed out, they can accomplish that goal by storing all numbers as 
(JSON) strings and using their application to decode/eval them.  This 
fix requires no changes to the CouchDB code.

I would not even change the encoder to deal with decimal points and 
precision.  I would advocate just making sure that the documentation is 
clear on this point.  In particular, it is probably necessary to 
document (as a breaking change that may require people to rewrite some 
of their applications) the fact that 1.2 may drop trailing zeros after 
the decimal point.

You cannot really promise to support different types of numbers without 
radically changing the CouchDB code.  You would then have to continually 
fight with JSON to get it to support something that is beyond its 
capabilities.  Maintenance would become a nightmare. Let's try to avoid 
that road....


On 2/13/2012 12:07 PM, Paul Joseph Davis (Commented) (JIRA) wrote:
>      [
> Paul Joseph Davis commented on COUCHDB-1407:
> --------------------------------------------
> As mentioned on the dev@ thread, I'm pretty dead set against this approach. While there
seems to be some sort of general consensus that storing numbers as uninterpreted bytes and
repeating them back is the way to go it really misses the entirety of the issue.
> First, CouchDB has never claimed to pass numbers around while keeping byte identical
representations. This patch attempts to change that drastically with a very large number of
consequences that we haven't begun to investigate.
> Secondly, if we were to actually consider going this route then we'd also be obliged
to start looking at every other place where we change representations internally as well.
> Thirdly, if we were to do that then we'd also have to get into all of the cases where
we're stricter than JSON specifically allows and then try and address all of those issues
as well.
> Basically, how about we just fix the encoder to spit out a decimal point and an appropriate
amount of precision and then start documenting our round tripping limitations.
>> JSON encoding of number changes
>> -------------------------------
>>                  Key: COUCHDB-1407
>>                  URL:
>>              Project: CouchDB
>>           Issue Type: Bug
>>           Components: HTTP Interface
>>     Affects Versions: 1.2
>>          Environment: Ubuntu 12.04 (alpha)
>>             Reporter: Adam Lofts
>>          Attachments: 0001-Only-validate-numbers-on-JSON-decoding.patch
>> JSON encoding of Number has changed from 1.0.2 to 1.2. JSON only defines Number but
this change causes issues in my app because python decodes the number as an int in 1.2.
>> Test case:
>> PORT=5985
>> curl -X DELETE http://localhost:$PORT/test-floats/
>> curl -X PUT http://localhost:$PORT/test-floats/
>> curl -X PUT http://localhost:$PORT/test-floats/doc1 -H "Content-Type: application/json"
-d "{ \"a\": 1.0 }"
>> curl http://localhost:$PORT/test-floats/doc1
>> Run against 1.0.2:
>> {"ok":true}
>> {"ok":true}
>> {"ok":true,"id":"doc1","rev":"1-78e61304147429d3d500aee7806fd26d"}
>> {"_id":"doc1","_rev":"1-78e61304147429d3d500aee7806fd26d","a":1.0}
>> Run against 1.2:
>> {"ok":true}
>> {"ok":true}
>> {"ok":true,"id":"doc1","rev":"1-78e61304147429d3d500aee7806fd26d"}
>> {"_id":"doc1","_rev":"1-78e61304147429d3d500aee7806fd26d","a":1}
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