Disable watcher whilst building, fixes #34

Author: mrbbot

package.json

@@ -15,8 +15,7 @@
   "types": "dist/index.d.ts",
   "files": [
     "dist",
-    "src",
-    "vendor"
+    "src"
   ],
   "scripts": {
     "build": "tsc -p tsconfig.build.json",

src/options/processor.ts

@@ -122,7 +122,7 @@ export class OptionsProcessor {
     this._scriptBlueprints[scriptPath] = new ScriptBlueprint(code, scriptPath);
   }
 
-  runCustomBuild(command: string, basePath?: string): Promise<void> {
+  runCustomBuild(command: string, basePath?: string): Promise<boolean> {
     return this._buildMutex.run(
       () =>
         new Promise((resolve) => {
@@ -132,12 +132,13 @@ export class OptionsProcessor {
             stdio: "inherit",
           });
           build.on("exit", (code) => {
-            if (code === 0) {
+            const succeeded = code === 0;
+            if (succeeded) {
               this.log.info("Build succeeded");
             } else {
               this.log.error(`Build failed with exit code ${code}`);
             }
-            resolve();
+            resolve(succeeded);
           });
         })
     );

src/options/watcher.ts

@@ -22,6 +22,7 @@ export class OptionsWatcher {
   private _watcher?: chokidar.FSWatcher;
   private _watchedPaths?: Set<string>;
   private _extraWatchedPaths?: Set<string>;
+  private _building = false;
 
   readonly initPromise: Promise<void>;
 
@@ -118,7 +119,7 @@ export class OptionsWatcher {
       .on("unlink", boundCallback);
   }
 
-  private _watchedPathCallback(eventPath: string) {
+  private async _watchedPathCallback(eventPath: string) {
     if (
       this._options?.buildWatchPath &&
       eventPath.startsWith(this._options.buildWatchPath)
@@ -129,13 +130,22 @@ export class OptionsWatcher {
         );
         // Re-run build, this should change a script triggering the watcher
         // again
-        void this._processor.runCustomBuild(
-          this._options.buildCommand,
-          this._options.buildBasePath
-        );
+        this._building = true;
+        try {
+          const succeeded = await this._processor.runCustomBuild(
+            this._options.buildCommand,
+            this._options.buildBasePath
+          );
+          if (succeeded) await this.reloadOptions(false);
+        } finally {
+          // Wait a little bit before starting to process watch events again
+          // to allow built file changes to come through
+          setTimeout(() => (this._building = false), 50);
+        }
       }
-    } else {
-      // If the path isn't in buildWatchPath, reload options and scripts
+    } else if (!this._building) {
+      // If the path isn't in buildWatchPath, reload options and scripts,
+      // provided we're not currently building
       this.log.debug(`${path.relative("", eventPath)} changed, reloading...`);
 
       // Log options is this was an options file, we don't want to spam the log
@@ -145,7 +155,7 @@ export class OptionsWatcher {
         eventPath === this._processor.packagePath ||
         eventPath === this._options?.envPath;
 
-      void this.reloadOptions(log);
+      await this.reloadOptions(log);
     }
   }
 

test/options/watcher.spec.ts

@@ -222,7 +222,6 @@ watchTest("rebuilds if watched build path changes", async (t) => {
   const watchedPath = path.join(tmp, "watch.txt");
   const scriptPath = path.join(tmp, "script.js");
   const relativeWatchedPath = path.relative("", watchedPath);
-  const relativeScriptPath = path.relative("", scriptPath);
   await fs.writeFile(watchedPath, "1", "utf8");
 
   const watcher = new OptionsWatcher(
@@ -247,7 +246,6 @@ watchTest("rebuilds if watched build path changes", async (t) => {
   await fs.writeFile(watchedPath, "2", "utf8");
   options = await next();
   t.is(log.debugs[0], `${relativeWatchedPath} changed, rebuilding...`);
-  t.is(log.debugs[1], `${relativeScriptPath} changed, reloading...`);
   t.is(options.scripts?.[scriptPath].code.trim(), `// build${os.EOL}// build`);
 });