handle anyhow exceptions in LS gracefully

Summary:
when processing an event returned an error response, we would still crash. instead, we should attempt to continue

this change affects any event that returns an anyhow error. however, the only 6 usages are in did_change events (the spot we are targeting to ignore errors)

Reviewed By: samwgoldman

Differential Revision: D87239356

fbshipit-source-id: f4a9a5866c74812a7324f16896a7788c138039f7

Author: kinto0

pyrefly/lib/lsp/non_wasm/server.rs

@@ -183,6 +183,7 @@ use serde::de::DeserializeOwned;
 use serde_json::Value;
 use starlark_map::small_map::SmallMap;
 use starlark_map::small_set::SmallSet;
+use tracing::error;
 use tracing::info;
 
 use crate::ModuleInfo;
@@ -612,15 +613,19 @@ pub fn lsp_loop(
             &mut canceled_requests,
             subsequent_mutation,
             event,
-        )? {
-            ProcessEvent::Continue => {
+        ) {
+            Ok(ProcessEvent::Continue) => {
                 let process_duration = process_start.elapsed().as_secs_f32();
                 info!(
                     "Language server processed event `{}` in {:.2}s ({:.2}s waiting)",
                     event_description, process_duration, queue_duration
                 );
             }
-            ProcessEvent::Exit => break,
+            Ok(ProcessEvent::Exit) => break,
+            Err(e) => {
+                // Log the error and continue processing the next event
+                error!("Error processing event `{}`: {:?}", event_description, e);
+            }
         }
     }
     info!("waiting for connection to close");