Colander missing=drop + Sphinx (via cornice-autodoc) result in 'not JSON serializable' while building docs

[evgenyz]

When building docs with Sphinx I got:

Exception occurred:
  File "/usr/lib64/python3.4/json/encoder.py", line 173, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <colander._drop object at 0x7f1cfc41ceb8> is not JSON serializable

The problem part is missing=drop declaration.

   title = SchemaNode(
        String(),
        location="body",
        type='non-empty string',
        missing=drop)

And if you change it to missing=None, problem goes away.

Everything is current from pip (in virtualenv), Python 3.4

[tisdall]

Can you provide your whole schema? missing=colander.drop only works on elements that are children of a MappingSchema.

[evgenyz]

It's just as simple as

class BrowseFiltersSchema(MappingSchema):
   title = SchemaNode(
      String(),
      location="body",
      type='non-empty string',
      missing=drop)

[almet]

Oh that's interesting. I don't know why this is happening and was working before. Did colander changed something in their implem? Is it a python 3k only problem?

I would be happy to fix this in the documentation. If you want you can submit a pull request and I will happily merge it. Otherwise I can just fix it

[evgenyz]

Actually, I don't really know what is the exact underlying problem that causes such a behavior (nor I have any patch). But I'll gladly provide support in fixing this for anyone who have ideas about where to dig.

[tisdall]

I'm wondering if this is related to #317

[evgenyz]

I've applied patch from #317 manually. Still no difference (it seems that this code path is not used in the docs generation process at all).

[tisdall]

@evgenyz - I wasn't suggesting using that patch... only that it may be related. #317 seems to fail some tests so I'm not even sure it fixes what it's mentioning.

[leplatrem]

We're moving the ext out the Cornice repo. Please reopen the issue in https://github.com/Cornices/cornice.ext.sphinx if still relevant and useful for your use case ;)