feat: Add compatibility with connection poolers on transaction mode

Update the hasql-transaction library to version 1.0.1

Add hints and kill thread at configuration read when using incompatible pooling modes: statement pooling and transaction pooling with prepared statements enabled.

test/fixtures/schema.sql

@@ -2041,9 +2041,10 @@ returns setof v2.parents as $$
   select * from v2.parents where id < $1;
 $$ language sql;
 
--- Only used for manually testing creating prepared statements
-create view prepared_statements as
-select * from pg_catalog.pg_prepared_statements;
+-- Used to test if prepared statements are used
+create function uses_prepared_statements() returns bool as $$
+  select count(name) > 0 from pg_catalog.pg_prepared_statements
+$$ language sql;
 
 create or replace function change_max_rows_config(val int, notify bool default false) returns void as $_$
 begin

test/io-tests/test_io.py

@@ -708,3 +708,22 @@ def test_invalid_role_claim_key_notify_reload(defaultenv):
         )
 
         postgrest.session.post("/rpc/reset_invalid_role_claim_key")
+
+def test_db_prepared_statements_enable(defaultenv):
+    "Should use prepared statements when the setting is enabled."
+
+    with run(env=defaultenv) as postgrest:
+        response = postgrest.session.post("/rpc/uses_prepared_statements")
+        assert response.text == "true"
+
+def test_db_prepared_statements_disable(defaultenv):
+    "Should not use any prepared statements when the setting is disabled."
+
+    env = {
+        **defaultenv,
+        "PGRST_DB_PREPARED_STATEMENTS": "false",
+    }
+
+    with run(env=env) as postgrest:
+        response = postgrest.session.post("/rpc/uses_prepared_statements")
+        assert response.text == "false"