[FIX] fiber, lifecycle: trigger a render during the fiber.complete

Have a component which does a render in its onWillPatch, onPatched, onMounted hooks.

Before this commit, the result was incorrect: the second rendering was not taken into account.

After this commit, those renderings are correctly applied at the price of a delayed render when the fiber
is in a critical state.

src/component/component_node.ts

@@ -136,13 +136,19 @@ export class ComponentNode<T extends typeof Component = typeof Component>
   }
 
   async render() {
-    const current = this.fiber;
+    let current = this.fiber;
+    if (current && current.root.locked) {
+      await Promise.resolve();
+      // situation may have changed after the microtask tick
+      current = this.fiber;
+    }
     if (current && !current.bdom && !fibersInError.has(current)) {
       return;
     }
     if (!this.bdom && !current) {
       return;
     }
+
     const fiber = makeRootFiber(this);
     this.fiber = fiber;
     this.app.scheduler.addFiber(fiber);

src/component/fibers.ts

@@ -118,9 +118,13 @@ export class RootFiber extends Fiber {
   willPatch: Fiber[] = [];
   patched: Fiber[] = [];
   mounted: Fiber[] = [];
+  // A fiber is typically locked when it is completing and the patch has not, or is being applied.
+  // i.e.: render triggered in onWillUnmount or in willPatch will be delayed
+  locked: boolean = false;
 
   complete() {
     const node = this.node;
+    this.locked = true;
     let current: Fiber | undefined = undefined;
     try {
       // Step 1: calling all willPatch lifecycle hooks
@@ -142,6 +146,11 @@ export class RootFiber extends Fiber {
       node.bdom!.patch(this.bdom!, Object.keys(node.children).length > 0);
       this.appliedToDom = true;
 
+      this.locked = false;
+      // unregistering the fiber before mounted since it can do another render
+      // and that the current rendering is obviously completed
+      node.fiber = null;
+
       // Step 4: calling all mounted lifecycle hooks
       let mountedFibers = this.mounted;
       while ((current = mountedFibers.pop())) {
@@ -163,9 +172,8 @@ export class RootFiber extends Fiber {
           }
         }
       }
-      // unregistering the fiber
-      node.fiber = null;
     } catch (e) {
+      this.locked = false;
       handleError({ fiber: current || this, error: e });
     }
   }
@@ -205,6 +213,11 @@ export class MountFiber extends RootFiber {
           mount(node.bdom!, this.target, firstChild);
         }
       }
+
+      // unregistering the fiber before mounted since it can do another render
+      // and that the current rendering is obviously completed
+      node.fiber = null;
+
       node.status = STATUS.MOUNTED;
       this.appliedToDom = true;
       let mountedFibers = this.mounted;
@@ -215,7 +228,6 @@ export class MountFiber extends RootFiber {
           }
         }
       }
-      node.fiber = null;
     } catch (e) {
       handleError({ fiber: current as Fiber, error: e });
     }