Re: Mention column name in error messages

On Wed, Jul 1, 2015 at 12:30 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

What seems more likely to lead to a usable patch is to arrange for the
extra information you want to be emitted as error "context", via an error
context callback that gets installed at the right times.  ...
...
with no need for int8in to be directly aware of the context.  You should
try adapting that methodology for the cases you're worried about.

Hi Tom (and others),

Sorry it took so long for me to follow up on this, hopefully I found a couple

a hours today to try writing another patch.

In any case, thanks for reviewing my first attempt and taking time to write

such a detailed critique... I've learned a lot!

I am now using the error context callback stack. The current column name

and column type are passed to the callback packed inside  a new structure

of type "TransformExprState".

Those information are then passed to `errhint` and will be presented to the

user later on (in case of coercion failure).

Please find the WIP patch attached.

(I've pushed the patch on my GH fork[1] too).