fix: Do not drop perms in git when not root

Forward port of 5f33040

Fix npm/cli#476 for pacote v10.

Fix #22

lib/util/git/opts.js

@@ -1,12 +1,13 @@
 const gitEnv = require('./env.js')
 module.exports = (_gitOpts = {}, opts = {}) => {
+  const isRoot = process.getuid && process.getuid() === 0
   const gitOpts = {
     env: gitEnv()
   }
-  if (+opts.uid && !isNaN(opts.uid)) {
+  if (isRoot && +opts.uid && !isNaN(opts.uid)) {
     gitOpts.uid = +opts.uid
   }
-  if (+opts.gid && !isNaN(opts.gid)) {
+  if (isRoot && +opts.gid && !isNaN(opts.gid)) {
     gitOpts.gid = +opts.gid
   }
   Object.assign(gitOpts, _gitOpts)

test/util/git/opts.js

@@ -1,19 +1,43 @@
 const t = require('tap')
 const gitOpts = require('../../../lib/util/git/opts.js')
 const gitEnv = require('../../../lib/util/git/env.js')
-t.match(gitOpts({
-  foo: 'bar',
-  env: { override: 'for some reason' },
-}, {
-  uid: 420,
-  gid: 69,
-  abc: 'def',
-}), {
-  foo: 'bar',
-  env: { override: 'for some reason' },
-  uid: 420,
-  gid: 69,
-  abc: undefined,
-}, 'copied relevant opts, not irrelevant ones')
 
 t.match(gitOpts().env, gitEnv(), 'got the git env by default')
+
+t.test('as root', t => {
+  process.getuid = () => 0
+  t.match(gitOpts({
+    foo: 'bar',
+    env: { override: 'for some reason' },
+  }, {
+    uid: 420,
+    gid: 69,
+    abc: 'def',
+  }), {
+    foo: 'bar',
+    env: { override: 'for some reason' },
+    uid: 420,
+    gid: 69,
+    abc: undefined,
+  }, 'copied relevant opts, not irrelevant ones')
+  t.end()
+})
+
+t.test('as non-root', t => {
+  process.getuid = () => 999
+  t.match(gitOpts({
+    foo: 'bar',
+    env: { override: 'for some reason' },
+  }, {
+    uid: 420,
+    gid: 69,
+    abc: 'def',
+  }), {
+    foo: 'bar',
+    env: { override: 'for some reason' },
+    uid: undefined,
+    gid: undefined,
+    abc: undefined,
+  }, 'do not set uid/gid as non-root')
+  t.end()
+})