fix(git): cleaner handling of git tarball streams when caching

lib/handlers/git/tarball.js

@@ -12,20 +12,17 @@ const path = require('path')
 const pipe = BB.promisify(require('mississippi').pipe)
 const rimraf = BB.promisify(require('rimraf'))
 const tar = require('tar-fs')
-const to = require('mississippi').to
 const uniqueFilename = require('unique-filename')
 
 const gitManifest = require('./manifest')
 
 module.exports = tarball
 function tarball (spec, opts) {
   opts = optCheck(opts)
-  let streamErr = null
-  const stream = new PassThrough().on('error', e => { streamErr = e })
+  const stream = new PassThrough()
   gitManifest(spec, opts).then(manifest => {
-    if (streamErr) { throw streamErr }
     return pipe(fromManifest(manifest, spec, opts), stream)
-  })
+  }, err => stream.emit('error', err))
   return stream
 }
 
@@ -46,7 +43,7 @@ function fromManifest (manifest, spec, opts) {
       return stream.emit('error', err)
     } else {
       stream.emit('reset')
-      withTmp(opts, tmp => {
+      return withTmp(opts, tmp => {
         if (streamError) { throw streamError }
         return cloneRepo(
           manifest._repo, manifest._ref, manifest._rawRef, tmp, opts
@@ -100,20 +97,9 @@ function packDir (spec, label, tmp, target, opts) {
     const cacher = cache.put.stream(
       opts.cache, cache.key('git-clone', label), opts
     )
-    cacher.once('error', err => packer.emit('error', err))
-    target.once('error', err => packer.emit('error', err))
-    packer.once('error', err => {
-      cacher.emit('error', err)
-      target.emit('error', err)
-    })
-    return pipe(packer, to((chunk, enc, cb) => {
-      cacher.write(chunk, enc, () => {
-        target.write(chunk, enc, cb)
-      })
-    }, done => {
-      cacher.end(() => {
-        target.end(done)
-      })
-    }))
+    return Promise.all([
+      pipe(packer, cacher),
+      pipe(packer, target)
+    ])
   }
 }