Save method behaviour changed?

[byrnejb]

I have this code in a working RoR-3.1 app:

  # save
  #
  # Override AR save method to catch DBMS specific errors
  # such as uniqueness constraint violations
  def save
    super
    rescue ActiveRecord::StatementInvalid => this_exception
      errors.add( currency_code, hll_ar_exception( this_exception ) )
      false
  end

In RoR-3.2.12  this no longer works.  Once I pass a save involving a duplicate record it never returns to the calling method.  For example:

  def save
    super
    fail( " die die die " )
    rescue ActiveRecord::StatementInvalid => this_exception

produces no output and does not throw an exception but in the log file I see this none-the-less:

PG::Error: ERROR:  duplicate key value violates unique constraint "idxu_currencies_currency_code"
DETAIL:  Key (currency_code)=(JPY) already exists.


How do I get the old behaviour back?  Calling save! instead super does not change the outcome.

[tamouse mailing lists]

I don't know the answer to your question, but I'm wondering if you can
circumvent the exception altogether by using valid? to see if it's a
valid record before attempting the save?

[James B. Byrne]

Rails validation for duplicate records is, to put it bluntly, a joke.
The code I wrote is intended to compensate for that fact by using the
DBMS as it is intended to be used. Up to the current version of Rails
this worked as I intended. Now it does not. I simply want to
discover what has changed and how I get around it.


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[Frederick Cheung]

On Tue, Mar 5, 2013 at 7:32 PM, byrnejb <byr...@harte-lyne.ca> wrote:

I have this code in a working RoR-3.1 app:

  # save
  #
  # Override AR save method to catch DBMS specific errors
  # such as uniqueness constraint violations

Where is this code? in a model, in module that is included into various models, somewhere else?

As an aside recent versions of rails raise ActiveRecord::RecordNotUnique in such cases, although this is a subclass of ActiveRecord::StatementInvalid so shouldn't change behaviour as far as you're concern. You're also changing the signature of save although I don't think that is related to the problem at hand.

  

Fred

[James B. Byrne]

On Wed, March 6, 2013 04:54, Frederick Cheung wrote:
> On Tue, Mar 5, 2013 at 7:32 PM, byrnejb <byr...@harte-lyne.ca> wrote:
>
>> I have this code in a working RoR-3.1 app:
>>
>> # save
>> #
>> # Override AR save method to catch DBMS specific errors
>> # such as uniqueness constraint violations
>>
>
> Where is this code? in a model, in module that is included into
> various models, somewhere else?

It is contained in a model:

class Currency < ActiveRecord::Base
include HLLActiveRow

after_save( :save_errors )
. . .

# save
#
# Override AR save method to catch DBMS specific errors
# such as uniqueness constraint violations

def save( * )
begin
puts( "I go" )
super
puts( "I return" )

rescue ActiveRecord::StatementInvalid => this_exception

errors.add( currency_code, hll_ar_exception( this_exception ) )

# errors.add_to_base(hll_ar_exception(this_exception))
false
end
end
. . .

I see that in the new persistence layer save is now deifined thus:



# File activerecord/lib/active_record/persistence.rb, line 82
def save(*)
begin
create_or_update
rescue ActiveRecord::RecordInvalid
false
end
end

Which bears some similarity to what I was doing for previous versions.
The rescue was added to persistence.rb in this commit two years ago:

https://github.com/rails/rails/commit/656e7b08073fa4e620a6d9ce0de554f8f5be96bb


But my code has been working subsequent to this up to v3.2. Something
else has changed to cause the effect I am now experiencing. The main
problem from my point of view is that I expect the save call to return
to the invoking method immediately after the point super is invoked
and that is not happening. That is what I find astonishing.

>
> As an aside recent versions of rails raise
> ActiveRecord::RecordNotUnique in
> such cases, although this is a subclass of
> ActiveRecord::StatementInvalid
> so shouldn't change behaviour as far as you're concern. You're also
> changing the signature of save although I don't think that is related
> to the problem at hand.

As far as I can see, save rescues but does not re-raise such
exceptions so I do not know where it is being returned from.

[James B. Byrne]

On Wed, March 6, 2013 04:54, Frederick Cheung wrote:
>
> As an aside recent versions of rails raise
> ActiveRecord::RecordNotUnique in
> such cases, although this is a subclass of
> ActiveRecord::StatementInvalid
> so shouldn't change behaviour as far as you're concern. You're also
> changing the signature of save although I don't think that is related
> to the problem at hand.
>

On: Tue Mar 5, 2013 1:48 pm ((PST)), "Les Nightingill"
codeh...@comcast.net lesnightingill wrote:
>
> perhaps the exception being raised is not
> ActiveRecord::StatementInvalid.
>
> suggest trying rescue with no exception specified to see if there is a
> different exception being raised.
>
> Les


Bingo! Rails-3.2.12 implements code similar to that I was providing
in hll_ar_exception( this_exception ) ) and actually returns the
exact message from PG that I was checking for therein.

def save( * )
begin
puts( "I go" )
super
puts( "I return" )

rescue => e
puts( e.inspect )
false
end
end


Using the default profile...
.................I go
#<ActiveRecord::RecordNotUnique: PG::Error: ERROR: duplicate key

value violates unique constraint "idxu_currencies_currency_code"
DETAIL: Key (currency_code)=(JPY) already exists.

: INSERT INTO "currencies" ("changed_at", "changed_by", "created_at",
"created_by", "currency_code", "currency_name", "discount_factor",
"effective_from", "fx_accounting_factor", "fx_accounting_margin",
"is_payable", "is_receivable", "premium_factor", "superseded_after")
VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14)
RETURNING "id">
..F-

(::) failed steps (::)

Mystery solved. Thanks.