fix(user-report): Make all fields but event-id optional

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+**Bug Fixes**:
+
+- Make all fields but event-id optional to fix regressions in user feedback ingestion. ([#886](https://github.com/getsentry/relay/pull/886))
+
 ## 20.12.1
 
 - No documented changes.

relay-general/src/protocol/user_report.rs

@@ -1,16 +1,40 @@
 use crate::protocol::EventId;
 
-use serde::{Deserialize, Serialize};
+use serde::{de::DeserializeOwned, Deserialize, Deserializer, Serialize};
 
 /// User feedback for an event as sent by the client to the userfeedback/userreport endpoint.
+///
+/// Historically the "schema" for user report has been "defined" as the set of possible
+/// keyword-arguments `sentry.models.UserReport` accepts. Anything the model constructor
+/// accepts goes.
+///
+/// For example, `{"email": null}` is only invalid because `UserReport(email=None).save()` is. SDKs
+/// may neither send this (historically, in Relay we relaxed this already), but more importantly
+/// the ingest consumer may never receive this... because it would end up crashing the ingest
+/// consumer (while in older versions of Sentry it would simply crash the endpoint).
+///
+/// The database/model schema is a bunch of not-null strings that have (pgsql) defaults, so that's
+/// how we end up with this struct definition.
 #[derive(Debug, Deserialize, Serialize)]
 pub struct UserReport {
     /// The event ID for which this user feedback is created.
     pub event_id: EventId,
     /// The user's name.
+    #[serde(default, deserialize_with = "null_to_default")]
     pub name: String,
     /// The user's email address.
+    #[serde(default, deserialize_with = "null_to_default")]
     pub email: String,
     /// Comments supplied by the user.
+    #[serde(default, deserialize_with = "null_to_default")]
     pub comments: String,
 }
+
+fn null_to_default<'de, D, V>(deserializer: D) -> Result<V, D::Error>
+where
+    D: Deserializer<'de>,
+    V: Default + DeserializeOwned,
+{
+    let opt = Option::deserialize(deserializer)?;
+    Ok(opt.unwrap_or_default())
+}