Improve handling of temporary file changes in watch mode

lib/snapshot-manager.js

@@ -355,10 +355,10 @@ class Manager {
 		const {dir, relFile, snapFile, snapPath, reportPath} = this;
 
 		if (this.updating && this.newBlocksByTitle.size === 0) {
-			return [
-				...cleanFile(snapPath),
-				...cleanFile(reportPath),
-			];
+			return {
+				changedFiles: [cleanFile(snapPath), cleanFile(reportPath)].flat(),
+				temporaryFiles: [],
+			};
 		}
 
 		if (!this.hasChanges) {
@@ -376,11 +376,14 @@ class Manager {
 
 		fs.mkdirSync(dir, {recursive: true});
 
-		const paths = [snapPath, reportPath];
-		const tmpfileCreated = tmpfile => paths.push(tmpfile);
+		const temporaryFiles = [];
+		const tmpfileCreated = file => temporaryFiles.push(file);
 		writeFileAtomic.sync(snapPath, buffer, {tmpfileCreated});
 		writeFileAtomic.sync(reportPath, reportBuffer, {tmpfileCreated});
-		return paths;
+		return {
+			changedFiles: [snapPath, reportPath],
+			temporaryFiles,
+		};
 	}
 }
 

lib/watcher.js

@@ -164,6 +164,7 @@ export default class Watcher {
 		this.testDependencies = [];
 		this.trackTestDependencies(api);
 
+		this.temporaryFiles = new Set();
 		this.touchedFiles = new Set();
 		this.trackTouchedFiles(api);
 
@@ -245,9 +246,13 @@ export default class Watcher {
 					return;
 				}
 
-				for (const file of evt.files) {
+				for (const file of evt.files.changedFiles) {
 					this.touchedFiles.add(file);
 				}
+
+				for (const file of evt.files.temporaryFiles) {
+					this.temporaryFiles.add(file);
+				}
 			});
 		});
 	}
@@ -393,6 +398,14 @@ export default class Watcher {
 				return false;
 			}
 
+			// Unlike touched files, temporary files are never cleared. We may see
+			// adds and unlinks detected separately, so we track the temporary files
+			// as long as AVA is running.
+			if (this.temporaryFiles.has(path)) {
+				debug('Ignoring known temporary file %s', path);
+				return false;
+			}
+
 			return true;
 		});