CLI: Reduce startup by using tiny-glob to only scan relevant paths

This follows-up 837af39, which introduced the ignore list to
the `--watch` mode when `run.restart()` calls `findFiles()`.

This was a big improvement for watch mode, but it still left two
major issues behind:

1. It did not apply to when running qunit normally (without --watch).
   This could be easily fixed by passing IGNORED_GLOBS in run()
   down to getFilesFromArgs/findFiles the same way.

2. We are still scanning all other top-level directories that are
   not ignored, even if they do not match any part of the glob pattern.

I investigated numerous matching libraries (picomatch, minimatch, etc.)
but it seems none of of them offer a way to determine whether
a given directory could contain a matching file. E.g. something
that returns false for `src/` when given `test/*.js`, but returns
true for `src/` if given `**/*.js`.

So rather than approaching it from the angle of a matching library,
I went looking for various "proper" glob libraries instead which
handle both the pattern matching and the directory scanning
responsibilities together.

I considered:

* isaacs/node-glob <http://npm.broofa.com/?q=glob@7.1.6>.
  10 dependencies, including 3 for minimatch. Not an option.

* mrmlnc/fast-glob <http://npm.broofa.com/?q=fast-glob@3.2.4>
  This uses picomatch, which is promising as being a popular
  dependency-free alternative to minimatch.
  But, it unfortunately does add up to 16 dependencies in total.

* Crafity/node-glob <http://npm.broofa.com/?q=node-glob@1.2.0>
  A mostly self-contained implementation with 2 dependencies
  ('async' and 'glob-to-regexp'). Unfortunately, it seems to
  not do a limited traversal but rather

* terkelg/tiny-glob <http://npm.broofa.com/?q=tiny-glob@0.2.6>
  Another self-contained implementation, with two local
  dependencies by the same author. Claims to be much faster
  than both fast-glob and node-glob. I think we have a winner.

Ref #1384.

package.json

@@ -39,7 +39,7 @@
     "commander": "2.12.2",
     "js-reporters": "1.2.1",
     "node-watch": "0.6.4",
-    "picomatch": "2.2.2"
+    "tiny-glob": "0.2.6"
   },
   "devDependencies": {
     "@babel/core": "7.11.1",

src/cli/run.js

@@ -6,13 +6,10 @@ const requireFromCWD = require( "./require-from-cwd" );
 const requireQUnit = require( "./require-qunit" );
 const utils = require( "./utils" );
 
-const IGNORED_GLOBS = [
-	".git",
-	"node_modules"
-].concat( utils.getIgnoreList( process.cwd() ) );
-
 const RESTART_DEBOUNCE_LENGTH = 200;
 
+const changedPendingPurge = [];
+
 let QUnit;
 
 function run( args, options ) {
@@ -108,12 +105,8 @@ run.restart = function( args ) {
 
 	this._restartDebounceTimer = setTimeout( () => {
 
-		const watchedFiles = utils.findFiles( process.cwd(), {
-			match: [ "**/*.js" ],
-			ignore: IGNORED_GLOBS
-		} );
-
-		watchedFiles.forEach( file => delete require.cache[ path.resolve( file ) ] );
+		changedPendingPurge.forEach( file => delete require.cache[ path.resolve( file ) ] );
+		changedPendingPurge.length = 0;
 
 		if ( QUnit.config.queue.length ) {
 			console.log( "Finishing current test and restarting..." );
@@ -158,6 +151,7 @@ run.watch = function watch() {
 		}
 	}, ( event, fullpath ) => {
 		console.log( `File ${event}: ${path.relative( baseDir, fullpath )}` );
+		changedPendingPurge.push( fullpath );
 		run.restart( args );
 	} );
 

src/cli/utils.js

@@ -2,7 +2,7 @@
 
 const fs = require( "fs" );
 const path = require( "path" );
-const picomatch = require( "picomatch" );
+const glob = require( "tiny-glob/sync" );
 
 function existsStat() {
 	try {
@@ -22,75 +22,48 @@ function getIgnoreList( baseDir ) {
 	return [];
 }
 
-function findFilesInternal( dir, options, result = [], prefix = "" ) {
-	fs.readdirSync( dir ).forEach( ( name ) => {
-		const fullName = path.join( dir, name );
-		const stat = existsStat( fullName );
-		if ( !stat ) {
-			return;
-		}
-		const prefixedName = prefix + name;
-		const isIgnore = options.ignores( prefixedName );
-
-		if ( isIgnore ) {
-			return;
-		}
-		if ( stat.isDirectory() ) {
-			findFilesInternal( fullName, options, result, prefixedName + "/" );
-		} else {
-			const isMatch = options.matchers( prefixedName );
-			if ( isMatch ) {
-				result.push( prefixedName );
-			}
-		}
-	} );
-	return result;
-}
-
-function findFiles( baseDir, options ) {
-	return findFilesInternal( baseDir, {
-		matchers: picomatch( options.match || [] ),
-		ignores: picomatch( options.ignore || [] )
-	} );
-}
-
 function getFilesFromArgs( args ) {
-	const globs = args.slice();
+	const patterns = args.slice();
 
 	// Default to files in the test directory
-	if ( !globs.length ) {
-		globs.push( "test/**/*.js" );
+	if ( !patterns.length ) {
+		patterns.push( "test/**/*.js" );
 	}
 
-	const files = [];
+	const files = new Set();
 	const filteredGlobs = [];
 
 	// For each of the potential globs, we check if it is a directory path and
 	// update it so that it matches the JS files in that directory.
-	globs.forEach( glob => {
-		const stat = existsStat( glob );
+	patterns.forEach( pattern => {
+		const stat = existsStat( pattern );
 
 		if ( stat && stat.isFile() ) {
 
-			// Remember known files to avoid (slow) directory-wide glob scanning.
+			// Optimisation:
+			// For non-glob simple files, skip (slow) directory-wide scanning.
 			// https://github.com/qunitjs/qunit/pull/1385
-			files.push( glob );
-		} else if ( stat && stat.isDirectory() ) {
-			filteredGlobs.push( `${glob}/**/*.js` );
+			files.add( pattern );
 		} else {
-			filteredGlobs.push( glob );
+			if ( stat && stat.isDirectory() ) {
+				pattern = `${pattern}/**/*.js`;
+			}
+			const results = glob( pattern, {
+				cwd: process.cwd(),
+				filesOnly: true,
+				flush: true
+			} );
+			for ( const result of results ) {
+				files.add( result );
+			}
 		}
 	} );
 
-	if ( filteredGlobs.length ) {
-		files.push.apply( files, findFiles( process.cwd(), { match: filteredGlobs } ) );
-	}
-
-	if ( !files.length ) {
+	if ( !files.size ) {
 		error( "No files were found matching: " + args.join( ", " ) );
 	}
 
-	return files;
+	return Array.from( files ).sort();
 }
 
 function error( message ) {
@@ -103,7 +76,6 @@ function capitalize( string ) {
 }
 
 module.exports = {
-	findFiles,
 	capitalize,
 	error,
 	getFilesFromArgs,

test/cli/fixtures/expected/tap-outputs.js

@@ -33,9 +33,9 @@ ok 1 Single > has a test
 
 	"qunit single.js double.js":
 `TAP version 13
-ok 1 Single > has a test
-ok 2 Double > has a test
-ok 3 Double > has another test
+ok 1 Double > has a test
+ok 2 Double > has another test
+ok 3 Single > has a test
 1..3
 # pass 3
 # skip 0
@@ -71,9 +71,9 @@ not ok 1 Throws match > bad
 
 	"qunit test single.js 'glob/**/*-test.js'":
 `TAP version 13
-ok 1 Single > has a test
-ok 2 A-Test > derp
-ok 3 Nested-Test > herp
+ok 1 A-Test > derp
+ok 2 Nested-Test > herp
+ok 3 Single > has a test
 ok 4 First > 1
 ok 5 Second > 1
 1..5
@@ -85,10 +85,10 @@ ok 5 Second > 1
 	"qunit --seed 's33d' test single.js 'glob/**/*-test.js'": `Running tests with seed: s33d
 TAP version 13
 ok 1 Second > 1
-ok 2 Nested-Test > herp
+ok 2 Single > has a test
 ok 3 First > 1
-ok 4 A-Test > derp
-ok 5 Single > has a test
+ok 4 Nested-Test > herp
+ok 5 A-Test > derp
 1..5
 # pass 5
 # skip 0