Thread: pgsql: Fix json_to_record() bug with nested objects.

pgsql: Fix json_to_record() bug with nested objects.

From
Tom Lane
Date:
Fix json_to_record() bug with nested objects.

A thinko concerning nesting depth caused json_to_record() to produce bogus
output if a field of its input object contained a sub-object with a field
name matching one of the requested output column names.  Per bug #13996
from Johann Visagie.

I added a regression test case based on his example, plus parallel tests
for json_to_recordset, jsonb_to_record, jsonb_to_recordset.  The latter
three do not exhibit the same bug (which suggests that we may be missing
some opportunities to share code...) but testing seems like a good idea
in any case.

Back-patch to 9.4 where these functions were introduced.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/a9d199f6d3b998929cdb8e8aa61e5cd8db9b220f

Modified Files
--------------
src/backend/utils/adt/jsonfuncs.c   |  2 +-
src/test/regress/expected/json.out  | 16 ++++++++++++++++
src/test/regress/expected/jsonb.out | 16 ++++++++++++++++
src/test/regress/sql/json.sql       |  7 +++++++
src/test/regress/sql/jsonb.sql      |  8 ++++++++
5 files changed, 48 insertions(+), 1 deletion(-)


Re: pgsql: Fix json_to_record() bug with nested objects.

From
Andrew Dunstan
Date:

On 03/02/2016 11:31 PM, Tom Lane wrote:
> I added a regression test case based on his example, plus parallel tests
> for json_to_recordset, jsonb_to_record, jsonb_to_recordset.  The latter
> three do not exhibit the same bug (which suggests that we may be missing
> some opportunities to share code...)



Not really. The jsonb variants don't do any re-parsing at all, so
lex_level simply doesn't come into play, and for json_to_recordset we
want things from lex_level 2, not 1, as the json is supposed to be an
array of objects instead of just an object.

That's not to say that the code can't be improved - It very probably can.

cheers

andrew