Fix watcher rebuild on page add and delete

src/functions/bundler/all-pages-esbuild-context-bundler.ts

@@ -32,6 +32,17 @@ type HydrationVirtualEntry = PageFiles & { tsx: string };
 // be recreated (entry points are fixed at context creation).
 let last_entry_keys: string[] | undefined = undefined;
 let last_root_file_path: string | undefined = undefined;
+// Local paths of the pages that made it into the current entry set. Pages
+// skipped at build time (e.g. created empty, no default export yet) are
+// absent, so the watcher can treat their later edits as structural.
+let last_entry_pages = new Set<string>();
+
+/**
+ * True when `local_path` is a hydration entry of the current esbuild context.
+ */
+export function isHydrationEntryPage(local_path: string): boolean {
+    return last_entry_pages.has(local_path);
+}
 
 function arraysEqual(a: string[], b: string[]): boolean {
     if (a.length !== b.length) return false;
@@ -133,6 +144,9 @@ export default async function allPagesESBuildContextBundler(params?: Params) {
 
             last_entry_keys = entry_keys;
             last_root_file_path = root_file_path;
+            last_entry_pages = new Set(
+                [...entryToPage.values()].map((p) => p.local_path),
+            );
         }
 
         await global.BUNEXT_BUNDLER_CTX!.rebuild();

src/functions/server/watcher-esbuild-ctx.ts

@@ -5,7 +5,10 @@ import grabDirNames from "../../utils/grab-dir-names";
 import fullRebuild from "./full-rebuild";
 import { AppData } from "../../data/app-data";
 import checkExcludedPatterns from "../../utils/check-excluded-patterns";
-import allPagesESBuildContextBundler from "../bundler/all-pages-esbuild-context-bundler";
+import allPagesESBuildContextBundler, {
+    isHydrationEntryPage,
+} from "../bundler/all-pages-esbuild-context-bundler";
+import grabAllPages from "../../utils/grab-all-pages";
 import serverPostBuildFn from "./server-post-build-fn";
 import { log } from "../../utils/log";
 import { logBuildErrorsOnce } from "../../utils/build-error-log";
@@ -26,12 +29,28 @@ export function restartWatcher() {
 
     if (Date.now() - last_watcher_restart < 1000) return;
 
+    // Files created between close() and the new watcher's initial scan
+    // completing emit no `add` (ignoreInitial treats them as pre-existing).
+    // Snapshot the page set so the new watcher can detect them on `ready`.
+    const pages_snapshot = grabPagesSnapshot();
+
     try {
         global.BUNEXT_PAGES_SRC_WATCHER.close();
     } catch (error) {}
     global.BUNEXT_PAGES_SRC_WATCHER = undefined;
     last_watcher_restart = Date.now();
-    watcherEsbuildCTX();
+    watcherEsbuildCTX({ pages_snapshot });
+}
+
+function grabPagesSnapshot(): string | undefined {
+    try {
+        return grabAllPages()
+            .map((p) => p.local_path)
+            .sort()
+            .join("\n");
+    } catch (error) {
+        return undefined;
+    }
 }
 
 /**
@@ -52,6 +71,9 @@ const REBUILD_DEBOUNCE_MS = 200;
 let pending_structural = false;
 let pending_content_file: string | undefined = undefined;
 let debounce_timer: ReturnType<typeof setTimeout> | undefined = undefined;
+// Guards against overlapping runners: BUNEXT_RECOMPILING alone is not enough
+// since the artifact tracker clears it mid-run.
+let runner_active = false;
 
 function scheduleRebuild() {
     if (debounce_timer) {
@@ -59,6 +81,14 @@ function scheduleRebuild() {
     }
     debounce_timer = setTimeout(async () => {
         debounce_timer = undefined;
+
+        // Another rebuild (fullRebuild, or a runner already looping) owns the
+        // bundler. Retry later rather than dropping the pending events.
+        if (runner_active || global.BUNEXT_RECOMPILING) {
+            scheduleRebuild();
+            return;
+        }
+
         try {
             await runRebuilds();
         } catch (error: any) {
@@ -69,9 +99,6 @@ function scheduleRebuild() {
                     (line) => log.error(line),
                 );
             }
-        } finally {
-            global.BUNEXT_RECOMPILING = false;
-            global.BUNEXT_IS_SERVER_COMPONENT = false;
         }
     }, REBUILD_DEBOUNCE_MS);
 }
@@ -84,9 +111,7 @@ function scheduleRebuild() {
  * tracker then queues the single-flighted SSR rebuild and pushes HMR updates.
  */
 async function runRebuilds() {
-    if (global.BUNEXT_RECOMPILING) {
-        return;
-    }
+    runner_active = true;
     global.BUNEXT_RECOMPILING = true;
     global.BUNEXT_IS_SERVER_COMPONENT = false;
 
@@ -140,6 +165,7 @@ async function runRebuilds() {
             }
         }
     } finally {
+        runner_active = false;
         global.BUNEXT_RECOMPILING = false;
         global.BUNEXT_IS_SERVER_COMPONENT = false;
     }
@@ -193,7 +219,9 @@ function buildIgnoredPatterns() {
     return ignored;
 }
 
-export default async function watcherEsbuildCTX() {
+export default async function watcherEsbuildCTX(params?: {
+    pages_snapshot?: string;
+}) {
     const pages_src_watcher = chokidar.watch(ROOT_DIR, {
         ignored: buildIgnoredPatterns(),
         persistent: true,
@@ -205,6 +233,17 @@ export default async function watcherEsbuildCTX() {
         (event, filePath) => handleEvent(event, filePath),
     );
 
+    const pages_snapshot = params?.pages_snapshot;
+    if (pages_snapshot !== undefined) {
+        pages_src_watcher.on("ready", () => {
+            const current = grabPagesSnapshot();
+            if (current !== undefined && current !== pages_snapshot) {
+                pending_structural = true;
+                scheduleRebuild();
+            }
+        });
+    }
+
     global.BUNEXT_PAGES_SRC_WATCHER = pages_src_watcher as any;
 }
 
@@ -252,10 +291,24 @@ function handleEvent(
         }
 
         if (event === "change") {
-            if (filename.match(TARGET_FILES_MATCH)) {
-                pending_content_file = full_file_path;
-                scheduleRebuild();
+            if (!filename.match(TARGET_FILES_MATCH)) {
+                return;
             }
+
+            // A page that isn't a hydration entry yet (e.g. created empty,
+            // then given its default export) needs the entry set recomputed;
+            // an incremental rebuild of the existing context would miss it.
+            if (
+                filename.match(/^src\/pages\//) &&
+                !filename.match(/^src\/pages\/api\/|\.server\.tsx?$/) &&
+                !checkExcludedPatterns({ path: filename }) &&
+                !isHydrationEntryPage(full_file_path)
+            ) {
+                pending_structural = true;
+            } else {
+                pending_content_file = full_file_path;
+            }
+            scheduleRebuild();
             return;
         }