Do not allow git replacement objects by default (#30)

Fix: https://github.com/github/npm-cli/issues/46

lib/clone.js

@@ -30,7 +30,7 @@ const pickManifest = require('npm-pick-manifest')
 const fs = require('fs')
 const mkdirp = require('mkdirp')
 
-module.exports = (repo, ref = 'HEAD', target = null, /* istanbul ignore next */ opts = {}) =>
+module.exports = (repo, ref = 'HEAD', target = null, opts = {}) =>
   revs(repo, opts).then(revs => clone(
     repo,
     revs,

lib/spawn.js

@@ -10,6 +10,11 @@ module.exports = (gitArgs, opts = {}) => {
 
   if (gitPath instanceof Error) { return Promise.reject(gitPath) }
 
+  // undocumented option, mostly only here for tests
+  const args = opts.allowReplace || gitArgs[0] === '--no-replace-objects'
+    ? gitArgs
+    : ['--no-replace-objects', ...gitArgs]
+
   const log = opts.log || procLog
   let retry = opts.retry
   if (retry === null || retry === undefined) {
@@ -22,11 +27,11 @@ module.exports = (gitArgs, opts = {}) => {
   }
   return promiseRetry((retry, number) => {
     if (number !== 1) {
-      log.silly('pacote', `Retrying git command: ${
-        gitArgs.join(' ')} attempt # ${number}`)
+      log.silly('git', `Retrying git command: ${
+        args.join(' ')} attempt # ${number}`)
     }
 
-    return spawn(gitPath, gitArgs, makeOpts(opts))
+    return spawn(gitPath, args, makeOpts(opts))
       .catch(er => {
         if (!shouldRetry(er.stderr, number)) {
           throw er