row_to_json data gets interpreted

I have to agree. IMHO, the json adapter should exist but its registration should not be automatic.

Mmm, i think you are right, the choice of adapting automatically json is questionable.

Eric, while we decide how to fix the problem you can disable the automatic adaptation using:

import psycopg2.extensions as ext
ext.string_types.pop(ext.JSON.values[0], None)
ext.string_types.pop(ext.JSONARRAY.values[0], None)

It's enough to do it only once and is idempotent anyway. If you guard it with an if hasattr(ext, 'JSON') it would work with any psycopg release.

I've written to the mailing list my ideas about the issue. Feel free to take part to the discussion.

The automatic cast of json was introduced in a major release (2.5): although the choice can be questioned (not that anybody did) it was done in a legitimate moment. Dropping automatic casting in 2.5.x would be a bad reaction; the right moment to think about a different behaviour is for 2.6.

You have plenty of options to work around the issue:

• use psycopg < 2.4.x, which is still being maintained (pip install "psycopg2<2.5" will give you the most up-to-date)
• cast your json as text in the query
• use the above snippet to unregister the json typecaster.

Sorry for the inconvenience.