Form parsing with data stream regression: Multipart(failed to lock multipart state)

[johnli360]

Rocket Version

0.5.1

Operating System

Ubuntu 22.04.5 LTS

Rust Toolchain Version

rustc 1.86.0

What happened?

Executing the following request: touch test && curl -F file=@test http://localhost:8000/upload, on the Rocket code provided in the test case on version 0.5.0 works (i.e. the request form is parsed without issue, and 200 OK is returned). On 0.5.1 I get:

POST /upload multipart/form-data:
   >> Matched: (upload) POST /upload multipart/form-data
   >> Data guard `Form < MyForm < '_ > >` failed: Errors([Error { name: None, value: None, kind: Multipart(failed to lock multipart state), entity: Form }]).
   >> Outcome: Error(400 Bad Request)
   >> No 400 catcher registered. Using Rocket default.
   >> Response succeeded.

Test Case

use rocket::data::Data;
use rocket::form::{DataField, Errors, Form, FromFormField};
use rocket::{FromForm, launch, post, routes};

struct Upload<'r> {
    data: Data<'r>,
}

#[rocket::async_trait]
impl<'v> FromFormField<'v> for Upload<'v> {
    async fn from_data(f: DataField<'v, '_>) -> Result<Self, Errors<'v>> {
        Ok(Upload { data: f.data })
    }
}

#[derive(FromForm)]
struct MyForm<'a> {
    file: Upload<'a>,
}

#[post("/upload", format = "multipart/form-data", data = "<form>")]
fn upload(form: Form<MyForm<'_>>) {
    println!("upload!");
}

#[launch]
fn rocket() -> _ {
    rocket::build().mount("/", routes![upload])
}

Log Output

-- configuration trace information --
   >> "address" parameter source: rocket::Config::default()
   >> "port" parameter source: rocket::Config::default()
   >> "workers" parameter source: rocket::Config::default()
   >> "max_blocking" parameter source: rocket::Config::default()
   >> "keep_alive" parameter source: rocket::Config::default()
   >> "ident" parameter source: rocket::Config::default()
   >> "ip_header" parameter source: rocket::Config::default()
   >> "limits" parameter source: rocket::Config::default()
   >> "temp_dir" parameter source: rocket::Config::default()
   >> "log_level" parameter source: `ROCKET_` environment variable(s)
   >> "shutdown" parameter source: rocket::Config::default()
   >> "cli_colors" parameter source: rocket::Config::default()
🔧 Configured for debug.
   >> address: 127.0.0.1
   >> port: 8000
   >> workers: 12
   >> max blocking threads: 512
   >> ident: Rocket
   >> IP header: X-Real-IP
   >> limits: bytes = 8KiB, data-form = 2MiB, file = 1MiB, form = 32KiB, json = 1MiB, msgpack = 1MiB, string = 8KiB
   >> temp dir: /tmp
   >> http/2: true
   >> keep-alive: 5s
   >> tls: disabled
   >> shutdown: ctrlc = true, force = true, signals = [SIGTERM], grace = 2s, mercy = 3s
   >> log level: debug
   >> cli colors: true
📬 Routes:
   >> (upload) POST /upload multipart/form-data
📡 Fairings:
   >> Shield (liftoff, response, singleton)
🛡️ Shield:
   >> Permissions-Policy: interest-cohort=()
   >> X-Content-Type-Options: nosniff
   >> X-Frame-Options: SAMEORIGIN
🚀 Rocket has launched from http://127.0.0.1:8000

--> /home/sejnld/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rocket-0.5.1/src/server.rs:77
	received request: Request {
    method: POST,
    uri: /upload,
    version: HTTP/1.1,
    headers: {
        "host": "localhost:8000",
        "user-agent": "curl/7.81.0",
        "accept": "*/*",
        "content-length": "196",
        "content-type": "multipart/form-data; boundary=------------------------954c7e155e174b71",
    },
    body: Body(
        Streaming,
    ),
}
POST /upload multipart/form-data:
   >> Matched: (upload) POST /upload multipart/form-data
   >> multipart field: Field { state: Mutex { data: MultipartState { buffer: StreamBuffer, boundary: "------------------------954c7e155e174b71", stage: ReadingFieldData, next_field_idx: 1, curr_field_name: Some("file"), curr_field_size_limit: 2097152, curr_field_size_counter: 0, constraints: Constraints { size_limit: SizeLimit { whole_stream: 2097152, per_field: 2097152, field_map: {} }, allowed_fields: None } }}, done: false, headers: {"content-disposition": "form-data; name=\"file\"; filename=\"test\"", "content-type": "application/octet-stream"}, content_disposition: ContentDisposition { field_name: Some("file"), file_name: Some("test") }, content_type: Some("application/octet-stream"), idx: 0 }
   >> Data guard `Form < MyForm < '_ > >` failed: Errors([Error { name: None, value: None, kind: Multipart(failed to lock multipart state), entity: Form }]).
   >> Outcome: Error(400 Bad Request)
   >> No 400 catcher registered. Using Rocket default.

--> /home/sejnld/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rocket-0.5.1/src/server.rs:166
	sending response: Response {
    status: 400,
    version: HTTP/1.1,
    headers: {
        "content-type": "text/html; charset=utf-8",
        "server": "Rocket",
        "permissions-policy": "interest-cohort=()",
        "x-content-type-options": "nosniff",
        "x-frame-options": "SAMEORIGIN",
        "content-length": "471",
    },
    body: Body(
        Streaming,
    ),
}
   >> Response succeeded.

Additional Context

No response

System Checks

• My bug report relates to functionality.
• I have tested against the latest Rocket release or a recent git commit.
• I have tested against the latest stable rustc toolchain.
• I was unable to find this issue previously reported.