Stream: bugs

Topic: basic-webserver sqlite constraint violation errors swallowed

Isaac Van Doren (Dec 24 2024 at 20:57):

It appears that constraint violations (uniqueness, not null, etc) are not reported as errors in Roc for the basic-webserver sqlite impl. Is this a known issue? I know there was some work on a new implementation so maybe this will be fixed by that work anyway.

With this db

create table test (username text unique);
insert into test (username) values ('isaac');

and this server

app [Model, init!, respond!] {
    pf: platform "platform/main.roc",
}

import pf.Http exposing [Request, Response]
import pf.Sqlite3

Model : {}

init! : {} => Result Model []
init! = \{} ->
    Ok {}

respond! : Request, Model => Result Response _
respond! = \_, _ ->
    _ =
        Sqlite3.execute! {
            path: "bug.db",
            query: "insert into test (username) values ('isaac')",
            bindings: [],
        }
        |> try
    Ok { status: 200, headers: [], body: [] }

Sqlite.execute! returns an Ok even though the insert failed for violating uniqueness constraint.

Brendan Hansknecht (Dec 24 2024 at 21:50):

We feed straight to the SQlite driver (though one of the more major updates got reverted, so not sure the exact state)

Ayaz Hafiz (Dec 24 2024 at 21:54):

bug is probably ignoring the error case here
https://github.com/roc-lang/basic-webserver/blob/ead72acb6e22c7cc74c2634d4bf83618ea1a924c/crates/roc_host/src/roc.rs#L378

Brendan Hansknecht (Dec 24 2024 at 21:55):

Might be, but I don't think insert returns anything via the cursor. I think with SQlite you have to separately request how many rows were inserted or updated to know if an insert failed.

Ayaz Hafiz (Dec 24 2024 at 22:00):

i think that's fine, the cursor will just return done immediately then. but the statement doesn't execute until you call next it looks like

Brendan Hansknecht (Dec 24 2024 at 22:00):

Ah yeah. Makes sense

Isaac Van Doren (Dec 25 2024 at 20:06):

Cool, thanks!

Last updated: Jul 26 2025 at 12:14 UTC