fix: do not crash when removing nameless packages

Fix: npm/npm#17858
Fix: npm/npm#18042
Fix: https://npm.community/t/issue-npm-dedupe-crash-with-typeerror-cannot-read-property-0-of-undefined/644/3
Close: #201

This fixes a bug where a package folder might have a package.json which
is missing or lacks a name property.  It also properly detects the
scoped-ness of a package folder even if the package name is not scoped,
since one might install `express@npm:@scope/express` and end up in that
state.

lib/unbuild.js

@@ -58,7 +58,9 @@ function rmStuff (pkg, folder, cb) {
   // if it's global, and folder is in {prefix}/node_modules,
   // then bins are in {prefix}/bin
   // otherwise, then bins are in folder/../.bin
-  var parent = pkg.name[0] === '@' ? path.dirname(path.dirname(folder)) : path.dirname(folder)
+  var dir = path.dirname(folder)
+  var scope = path.basename(dir)
+  var parent = scope.charAt(0) === '@' ? path.dirname(dir) : dir
   var gnm = npm.dir
   // gnm might be an absolute path, parent might be relative
   // this checks they're the same directory regardless

test/tap/uninstall-package.js

@@ -18,7 +18,8 @@ var json = {
   version: '0.0.0',
   dependencies: {
     underscore: '~1.3.1',
-    request: '~0.9.0'
+    request: '~0.9.0',
+    '@isaacs/namespace-test': '1.x'
   }
 }
 
@@ -69,6 +70,27 @@ test('returns a list of removed items', function (t) {
   })
 })
 
+test('does not fail if installed package lacks a name somehow', function (t) {
+  const scope = path.resolve(pkg, 'node_modules/@isaacs')
+  const scopePkg = path.resolve(scope, 'namespace-test')
+  const pj = path.resolve(scopePkg, 'package.json')
+  fs.writeFileSync(pj, JSON.stringify({
+    lol: 'yolo',
+    name: 99
+  }))
+  common.npm(
+    ['uninstall', '@isaacs/namespace-test'],
+    EXEC_OPTS,
+    function (err, code, stdout, stderr) {
+      if (err) throw err
+      t.equal(code, 0, 'should exit successfully')
+      t.has(stdout, /removed 1 package in/)
+      t.notOk(fs.existsSync(scope), 'scoped package removed')
+      t.end()
+    }
+  )
+})
+
 test('cleanup', function (t) {
   cleanup()
   t.end()