ep: Don't fail on lines with inference errors (#47406)

Release Notes:

- N/A

crates/edit_prediction_cli/src/example.rs

@@ -75,10 +75,21 @@ pub struct ExamplePrompt {
 pub struct ExamplePrediction {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub actual_patch: Option<String>,
+    #[serde(deserialize_with = "deserialize_null_as_empty_string")]
     pub actual_output: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub error: Option<String>,
     pub provider: PredictionProvider,
 }
 
+fn deserialize_null_as_empty_string<'de, D>(deserializer: D) -> Result<String, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let opt = Option::<String>::deserialize(deserializer)?;
+    Ok(opt.unwrap_or_default())
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct ExampleScore {
     pub delta_chr_f: f32,

crates/edit_prediction_cli/src/predict.rs

@@ -197,6 +197,7 @@ pub async fn run_prediction(
             .push(ExamplePrediction {
                 actual_patch: None,
                 actual_output: String::new(),
+                error: None,
                 provider,
             });
 
@@ -302,6 +303,7 @@ async fn predict_anthropic(
     let prediction = ExamplePrediction {
         actual_patch: Some(actual_patch),
         actual_output,
+        error: None,
         provider: if batched {
             PredictionProvider::Teacher(version)
         } else {