ON DELETE triggers don't work as documented

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Your name : Mike Glover
Your email address : mpg4(at)mdi(dot)cc

System Configuration
---------------------
Architecture (example: Intel Pentium) : Mixed ix86

Operating System (example: Linux 2.0.26 ELF) : Linux 2.4.x

PostgreSQL version (example: PostgreSQL-7.2.1): PostgreSQL-7.2.1

Compiler used (example: gcc 2.95.2) : gcc 2.96

Please enter a FULL description of your problem:
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The docs state (section 23.9):

If a non-NULL value is returned then the operation proceeds with that row value. Note that returning a row value different from the original value of NEW alters the row that will be inserted or updated.

the above suggests that returning NEW for a delete should cause the delete to proceed. In fact, I've found it necessary to return a record with the row format of the table and all empty fields.

Please describe a way to repeat the problem. Please try to provide a
concise reproducible example, if at all possible:
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db=# create table test (field1 int, field2 text);
CREATE
db=# create or replace function test_trigger () returns opaque as '
mdisys'# DECLARE
mdisys'# BEGIN
mdisys'# return NEW;
mdisys'# END
mdisys'# ' language plpgsql;
CREATE
db=# create trigger run_test_trigger before delete on test for each row execute procedure test_trigger();
CREATE
db=# insert into test values (1, 'foo');
INSERT 123700 1
db=# insert into test values (2, 'bar');
INSERT 123701 1
db=# delete from test where field1=1;
DELETE 0
db=# select * from test;
field1 | field2
--------+--------
1 | foo
2 | bar
(2 rows)

db=#

If you know how this problem might be fixed, list the solution below:
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I believe this is a documentation bug.