update.php from D5 to head doesn't work on pg7.4 - because you can't add constraints or default in the same statement as column add.
I wrote the schema SQL generator for PostgreSQL and I guess I suspected it would not work with 7.4. I developed on Windows which does not support pg 7.4 so I had no way to test with that platform. I probably should have made some noise about that. I don't know enough about the pg-using community to know whether support for 7.4 matters.
Sure, it can be patched (and i've got one i'll submit)
If you have a patch, I suggest submitting it. The conversation about what to do re: pg 7.4 can then happen in that thread. Have you tried schema.module on pg 7.4? I'm curious to know whether its database schema inspection code works... Thanks, Barry