fix: account for directories and files prefixed with ./ (#140)

lib/index.js

@@ -294,8 +294,13 @@ class PackWalker extends IgnoreWalker {
 
     // if we have a files array in our package, we need to pull rules from it
     if (files) {
-      for (const file of files) {
+      for (let file of files) {
         // invert the rule because these are things we want to include
+        if (file.startsWith('/')) {
+          file = file.slice(1)
+        } else if (file.startsWith('./')) {
+          file = file.slice(2)
+        }
         const inverse = `!${file}`
         try {
           // if an entry in the files array is a specific file, then we need to include it as a
@@ -305,7 +310,7 @@ class PackWalker extends IgnoreWalker {
           // if we have a file and we know that, it's strictly required
           if (stat.isFile()) {
             strict.unshift(inverse)
-            this.requiredFiles.push(file.startsWith('/') ? file.slice(1) : file)
+            this.requiredFiles.push(file)
           } else if (stat.isDirectory()) {
             // otherwise, it's a default ignore, and since we got here we know it's not a pattern
             // so we include the directory contents

test/package-json-dir-with-slashes.js

@@ -0,0 +1,42 @@
+// In v1, this would exclude the 'lib/two.js' file, because
+// the .npmignore is deeper in the tree and thus had higher
+// precedence.  In v2, because /lib/two.js is in the files
+// list as a file path, it will be included no matter what.
+'use strict'
+
+const Arborist = require('@npmcli/arborist')
+const t = require('tap')
+const packlist = require('../')
+
+const pkg = t.testdir({
+  'package.json': JSON.stringify({
+    files: [
+      '/lib',
+      './lib2',
+    ],
+  }),
+  lib: {
+    'one.js': 'one',
+    'two.js': 'two',
+    'tre.js': 'tre',
+    'for.js': 'for',
+    '.npmignore': 'two.js',
+  },
+  lib2: {
+    'fiv.js': 'fiv',
+    '.DS_Store': 'a store of ds',
+  },
+})
+
+t.test('package with slash directories', async (t) => {
+  const arborist = new Arborist({ path: pkg })
+  const tree = await arborist.loadActual()
+  const files = await packlist(tree)
+  t.same(files, [
+    'lib2/fiv.js',
+    'lib/for.js',
+    'lib/one.js',
+    'lib/tre.js',
+    'package.json',
+  ])
+})

test/package-json-files-with-slashes.js

@@ -27,7 +27,7 @@ const pkg = t.testdir({
   },
 })
 
-t.test('package with negated files', async (t) => {
+t.test('package with slash files', async (t) => {
   const arborist = new Arborist({ path: pkg })
   const tree = await arborist.loadActual()
   const files = await packlist(tree)