runtime: Remove unnecessary block_in_place + block_on

Subgraph runners execute on dedicated OS threads inside
graph::block_on(runner.run()), so process_mapping_trigger is already
in a valid async context. The block_in_place + block_on combo only
existed to allow the nested block_on call, but since all WASM host
functions are async and use .await, there is no need to exit and
re-enter the runtime context.

Replace with a direct .await using FutureExt::catch_unwind for panic
recovery.

Author: lutter

runtime/wasm/src/host.rs

@@ -1,9 +1,10 @@
 use std::cmp::PartialEq;
-use std::panic;
+use std::panic::AssertUnwindSafe;
 use std::time::Instant;
 
 use anyhow::Context;
 use async_trait::async_trait;
+use graph::futures03::FutureExt as _;
 
 use graph::blockchain::{Blockchain, HostFn, RuntimeAdapter};
 use graph::components::store::{EnsLookup, SubgraphFork};
@@ -194,31 +195,26 @@ where
         let logger_for_panic = logger.cheap_clone();
         let metrics_for_trigger = metrics.cheap_clone();
 
-        // Run the WASM instantiation and handler inside block_in_place.
-        // This tells tokio "I'm about to block" so it can move async work
-        // to other threads, preventing executor starvation.
-        let result = tokio::task::block_in_place(|| {
-            let handle_fut = async {
-                let _section = metrics_for_trigger.stopwatch.start_section("module_init");
-                let module = crate::module::WasmInstance::from_valid_module_with_ctx(
-                    valid_module,
-                    ctx,
-                    metrics_for_trigger.cheap_clone(),
-                    experimental_features,
-                )
-                .await
-                .context("module instantiation failed")?;
-                drop(_section);
-
-                let _section = metrics_for_trigger.stopwatch.start_section("run_handler");
-                if ENV_VARS.log_trigger_data {
-                    debug!(logger_for_panic, "trigger data: {:?}", trigger);
-                }
-                module.handle_trigger(trigger).await
-            };
-
-            panic::catch_unwind(panic::AssertUnwindSafe(|| graph::block_on(handle_fut)))
-        });
+        let handle_fut = async {
+            let _section = metrics_for_trigger.stopwatch.start_section("module_init");
+            let module = crate::module::WasmInstance::from_valid_module_with_ctx(
+                valid_module,
+                ctx,
+                metrics_for_trigger.cheap_clone(),
+                experimental_features,
+            )
+            .await
+            .context("module instantiation failed")?;
+            drop(_section);
+
+            let _section = metrics_for_trigger.stopwatch.start_section("run_handler");
+            if ENV_VARS.log_trigger_data {
+                debug!(logger_for_panic, "trigger data: {:?}", trigger);
+            }
+            module.handle_trigger(trigger).await
+        };
+
+        let result = AssertUnwindSafe(handle_fut).catch_unwind().await;
 
         let result = match result {
             Ok(result) => result,