feat(git): accept git path option

lib/util/git.js

@@ -74,10 +74,10 @@ function fullClone (repo, committish, target, opts) {
   if (process.platform === 'win32') {
     gitArgs.push('--config', 'core.longpaths=true')
   }
-  return execGit(gitArgs, { cwd: target }).then(() => {
-    return execGit(['init'], { cwd: target })
+  return execGit(gitArgs, { cwd: target }, opts).then(() => {
+    return execGit(['init'], { cwd: target }, opts)
   }).then(() => {
-    return execGit(['checkout', committish || 'HEAD'], { cwd: target })
+    return execGit(['checkout', committish || 'HEAD'], { cwd: target }, opts)
   }).then(() => {
     return updateSubmodules(target, opts)
   }).then(() => headSha(target, opts))
@@ -182,7 +182,7 @@ function revs (repo, opts) {
 module.exports._exec = execGit
 function execGit (gitArgs, gitOpts, opts) {
   opts = optCheck(opts)
-  return checkGit().then(gitPath => {
+  return checkGit(opts).then(gitPath => {
     return promiseRetry((retry, number) => {
       if (number !== 1) {
         opts.log.silly('pacote', 'Retrying git command: ' + gitArgs.join(' ') + ' attempt # ' + number)
@@ -206,7 +206,7 @@ function execGit (gitArgs, gitOpts, opts) {
 module.exports._spawn = spawnGit
 function spawnGit (gitArgs, gitOpts, opts) {
   opts = optCheck(opts)
-  return checkGit().then(gitPath => {
+  return checkGit(opts).then(gitPath => {
     return promiseRetry((retry, number) => {
       if (number !== 1) {
         opts.log.silly('pacote', 'Retrying git command: ' + gitArgs.join(' ') + ' attempt # ' + number)
@@ -246,8 +246,10 @@ function mkOpts (_gitOpts, opts) {
   return gitOpts
 }
 
-function checkGit () {
-  if (!GITPATH) {
+function checkGit (opts) {
+  if (opts.git) {
+    return BB.resolve(opts.git)
+  } else if (!GITPATH) {
     const err = new Error('No git binary found in $PATH')
     err.code = 'ENOGIT'
     return BB.reject(err)

lib/util/opt-check.js

@@ -21,6 +21,7 @@ module.exports = figgyPudding({
   fullMetadata: 'full-metadata',
   'full-metadata': { default: false },
   gid: {},
+  git: {},
   includeDeprecated: { default: true },
   'include-deprecated': 'includeDeprecated',
   integrity: {},

test/util.git.js

@@ -15,3 +15,13 @@ test('executes git binary', {
     t.match(stdout, /^git version/, 'successfully ran git')
   })
 })
+
+const systemNode = which.sync('node')
+
+test('acknowledges git option', t => {
+  return git._exec(['--version'], null, {
+    git: systemNode
+  }).spread(stdout => {
+    t.equals(stdout.trim(), process.version)
+  })
+})