Thread: pgsql: Disallow USING clause when altering type of generated column

Disallow USING clause when altering type of generated column

This does not make sense.  It would write the output of the USING
clause into the converted column, which would violate the generation
expression.  This adds a check to error out if this is specified.

There was a test for this, but that test errored out for a different
reason, so it was not effective.

Reported-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Yugo NAGATA <nagata@sraoss.co.jp>
Discussion: https://www.postgresql.org/message-id/flat/c7083982-69f4-4b14-8315-f9ddb20b9834%40eisentraut.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/4d68a043245a6947d676a216aaac0714bcaf97d5

Modified Files
--------------
src/backend/commands/tablecmds.c        | 13 ++++++++++++-
src/test/regress/expected/generated.out |  3 ++-
2 files changed, 14 insertions(+), 2 deletions(-)