Why does op.add_column explicitly not support primary_key?

[Chais]

It's been remarked in #1232 explicitly doesn't support primary_key and I can see this in the generated MySQL.
My question is now: Why?

ALTER TABLE mytabl ADD COLUMN id INTEGER PRIMARY KEY AUTO_INCREMENT;

works perfectly fine, so why not have alembic spit that out?

[zzzeek]

shrugs, I guess I was too lazy to read PG docs.. will fix momentarily possibly, at some point

[zzzeek]

the correct reason is that the SQLAlchemy compiler does not generate the inline PRIMARY KEY directive in a column specification, it always generates table level PRIMARY KEY with CREATE TABLE. so alembic does not have a cross-dialect column compilation routine that supports this, it would either have to create its own (not possible, because we rely on dialects to generate correct per-dialect SQL) or amend the output from the dialect column specification (would work for prominent dialects but might cause problems on third party dialects which dont support the same syntax).

i've reopened #1232 but im not sure I want to hack a fix here.

[Chais]

The example above is MySQL, though.