fix deadlock in file.rs

compiler/load/src/file.rs

@@ -293,7 +293,7 @@ struct ModuleCache<'a> {
     sources: MutMap<ModuleId, (PathBuf, &'a str)>,
 }
 
-fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) -> BuildTask<'a> {
+fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) -> Vec<BuildTask<'a>> {
     // we blindly assume all dependencies are met
 
     match state.dependencies.status.get_mut(&(module_id, phase)) {
@@ -301,11 +301,20 @@ fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) ->
             // start this phase!
             *current = Status::Pending;
         }
-        Some(Status::Pending) | Some(Status::Done) => {
+        Some(Status::Pending) => {
             // don't start this task again!
-            todo!();
+            return vec![];
+        }
+        Some(Status::Done) => {
+            // don't start this task again, but tell those waiting for it they can continue
+            return state
+                .dependencies
+                .notify(module_id, phase)
+                .into_iter()
+                .map(|(module_id, phase)| start_phase(module_id, phase, state))
+                .flatten()
+                .collect();
         }
-
         None => match phase {
             Phase::LoadHeader => {
                 // this is fine, mark header loading as pending
@@ -321,6 +330,7 @@ fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) ->
         },
     }
 
+    let task = {
         match phase {
             Phase::LoadHeader => {
                 let dep_name = state
@@ -350,7 +360,8 @@ fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) ->
 
                 let deps_by_name = &parsed.deps_by_name;
                 let num_deps = deps_by_name.len();
-            let mut dep_idents: MutMap<ModuleId, IdentIds> = IdentIds::exposed_builtins(num_deps);
+                let mut dep_idents: MutMap<ModuleId, IdentIds> =
+                    IdentIds::exposed_builtins(num_deps);
 
                 let State {
                     ident_ids_by_module,
@@ -496,6 +507,9 @@ fn start_phase<'a>(module_id: ModuleId, phase: Phase, state: &mut State<'a>) ->
                 }
             }
         }
+    };
+
+    vec![task]
 }
 
 #[derive(Debug)]
@@ -1329,6 +1343,21 @@ where
     .unwrap()
 }
 
+fn start_tasks<'a>(
+    work: MutSet<(ModuleId, Phase)>,
+    state: &mut State<'a>,
+    injector: &Injector<BuildTask<'a>>,
+    worker_listeners: &'a [Sender<WorkerMsg>],
+) -> Result<(), LoadingProblem> {
+    for (module_id, phase) in work {
+        for task in start_phase(module_id, phase, state) {
+            enqueue_task(&injector, worker_listeners, task)?
+        }
+    }
+
+    Ok(())
+}
+
 fn update<'a>(
     mut state: State<'a>,
     msg: Msg<'a>,
@@ -1384,19 +1413,11 @@ fn update<'a>(
 
             state.module_cache.headers.insert(header.module_id, header);
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
-
-                enqueue_task(&injector, worker_listeners, task)?
-            }
 
             let work = state.dependencies.notify(home, Phase::LoadHeader);
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
-
-                enqueue_task(&injector, worker_listeners, task)?
-            }
 
             Ok(state)
         }
@@ -1412,11 +1433,7 @@ fn update<'a>(
 
             let work = state.dependencies.notify(module_id, Phase::Parse);
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
-
-                enqueue_task(&injector, worker_listeners, task)?
-            }
 
             Ok(state)
         }
@@ -1452,11 +1469,7 @@ fn update<'a>(
                 .dependencies
                 .notify(module_id, Phase::CanonicalizeAndConstrain);
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
-
-                enqueue_task(&injector, worker_listeners, task)?
-            }
 
             Ok(state)
         }
@@ -1503,11 +1516,7 @@ fn update<'a>(
                     .notify(module_id, Phase::CanonicalizeAndConstrain),
             );
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
-
-                enqueue_task(&injector, worker_listeners, task)?
-            }
 
             Ok(state)
         }
@@ -1594,11 +1603,7 @@ fn update<'a>(
                     state.constrained_ident_ids.insert(module_id, ident_ids);
                 }
 
-                for (module_id, phase) in work {
+                start_tasks(work, &mut state, &injector, worker_listeners)?;
-                    let task = start_phase(module_id, phase, &mut state);
-
-                    enqueue_task(&injector, worker_listeners, task)?
-                }
             }
 
             Ok(state)
@@ -1646,11 +1651,8 @@ fn update<'a>(
                 .dependencies
                 .notify(module_id, Phase::FindSpecializations);
 
-            for (module_id, phase) in work {
+            start_tasks(work, &mut state, &injector, worker_listeners)?;
-                let task = start_phase(module_id, phase, &mut state);
 
-                enqueue_task(&injector, worker_listeners, task)?
-            }
             Ok(state)
         }
         MadeSpecializations {
@@ -1718,11 +1720,7 @@ fn update<'a>(
                 // the originally requested module, we're all done!
                 return Ok(state);
             } else {
-                for (module_id, phase) in work {
+                start_tasks(work, &mut state, &injector, worker_listeners)?;
-                    let task = start_phase(module_id, phase, &mut state);
-
-                    enqueue_task(&injector, worker_listeners, task)?
-                }
             }
 
             Ok(state)