`IF NOT EXISTS` not supported on `CREATE TABLE`

[aminalplanet]

It seems like pg-mem does not support IF NOT EXISTS on table creation. A few of my tables require other tables to exist beforehand, so for tests I am auto-creating any table dependencies as I go. Since some of those dependencies overlap, I rely on IF NOT EXISTS to smooth things out when a table has already been auto-created beforehand.

I'll dive into the codebase and see if I can implement this feature myself, but documenting it here all the same.

To Reproduce

Fails on playground:

CREATE TABLE IF NOT EXISTS "user" ("id" SERIAL NOT NULL, "name" text NOT NULL, PRIMARY KEY ("id"));
CREATE TABLE IF NOT EXISTS "user" ("id" SERIAL NOT NULL, "name" text NOT NULL, PRIMARY KEY ("id"));

Error

🔨 Not supported 🔨 : The query you ran generated an AST which parts have not been read by the query planner. This means that those parts could be ignored:

    ⇨ .columns[0].constraints[0].type ("not null")
    ⇨ .columns[1].constraints[0].type ("not null")
    ⇨ .constraints[0].type ("primary key")
    ⇨ .constraints[0].columns[0].name ("id")
    ⇨ .constraints[0].columns ([{"name":"id","_location":{"start":209,"end":213}}])

👉 pg-mem is work-in-progress, and it would seem that you've hit one of its limits.

*️⃣ Reconsituted failed SQL statement: CREATE TABLE IF NOT EXISTS "user"  (id serial   not null  , name text   not null  ,  primary key (id)  )