validate corrupts patches when adding array then appending

[albanm]

Hello,

You can try the following code:

var jsonpatch = require('./src/json-patch');
var patches = [{op: 'add', value: [], path: '/foo'}, {op: 'add', value: 2, path: '/foo/-'}];
jsonpatch.validate(patches, {});
console.log(patches);

It outputs:

[ { op: 'add', value: [ 2 ], path: '/foo' },
  { op: 'add', value: 2, path: '/foo/-' } ]

As you can see the value object of the first patch has been modified. Instead of an empty array it is now an array containing the value of the second patch.

[baranga]

This also works with objects:

var jsonpatch = require('./src/json-patch');
var patches = [{op: 'add', value: {}, path: '/foo'}, {op: 'add', value: 'a', path: '/foo/a'}];
jsonpatch.validate(patches, {});
console.log(patches);

Output:

[ { op: 'add', value: { a: 'a' }, path: '/foo' },
  { op: 'add', value: 'a', path: '/foo/a' } ]

Looks like patch value gets copied by reference instead of deep copy.

[MarkHerhold]

How does this work with undefined values? IIRC, this repo tries to respect
undefined fields despite them not being serializable to/from JSON (which is
a bad idea anyway IMO) .

On Tue, May 3, 2016, 9:53 AM baranga notifications@github.com wrote:

This also works with objects:

var jsonpatch = require('./src/json-patch');
var patches = [{op: 'add', value: {}, path: '/foo'}, {op: 'add', value: 'a', path: '/foo/a'}];
jsonpatch.validate(patches, {});
console.log(patches);

Looks like patch value gets copied by reference instead of deep copy.

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#76 (comment)

[baranga]

@MarkHerhold I don't understand your question. How to deep copy something with a undefined in it? That should not happen because you can not express a patch operation with value of undefined.

[MarkHerhold]

@baranga You are right, it shouldn't happen in the traditional JSON sense, but JSON-Patch treats undefined as a first-class citizen. ;)

Here's an example:

> var jsonpatch = require('fast-json-patch')
undefined
> var obj = {};
undefined
> jsonpatch.apply(obj, [{op: 'add', path:"/thing", value: undefined}]);
true
> Object.keys(obj)
[ 'thing' ]
> obj.thing
undefined

See also #90 #60 #32 and probably others...

[baranga]

@MarkHerhold That still works. deepClone only does a JSON encode/decode roundtrip if value is of type object. See json-patch-duplex.ts.

Is that behaviour covered by the test suites? I run them with my modifications and got same errors as on master.

[baranga]

Ok, now I see the issue:

> var jsonpatch = require('./src/json-patch-duplex')
undefined
> var obj = {}
undefined
> jsonpatch.apply(obj, [{op: 'add', path: '/deepThing', value: {undef: undefined}}])
true
> Object.keys(obj)
[ 'deepThing' ]
> Object.keys(obj.deepThing)
[]

But the last should be:

> Object.keys(obj.deepThing)
[ 'undef' ]

[baranga]

@MarkHerhold So right now something broken can't be fixed because the lib supports a non standard feature?

[MarkHerhold]

No, there are other more expensive clone strategies and implementations.
e.g. lodash's clone.

I personally think we should cut a v1 release, dropping support for
undefined and apply your PR.

On Wed, May 4, 2016, 3:19 AM baranga notifications@github.com wrote:

@MarkHerhold https://github.com/MarkHerhold So right now something
broken can't be fixed because the lib supports a non standard feature?

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#76 (comment)

[warpech]

The part regarding undefined is fixed in 1.0.0

[baranga]

This issue is still present. I updated my possible fix #100 to newest version: #134. This comes with a speed penalty.