packer communicator: use iochan.LineReader instead of iochan.LineReader(in)

* as it's the recommended way

go.mod

@@ -113,7 +113,7 @@ require (
 	github.com/mitchellh/go-fs v0.0.0-20180402234041-7b48fa161ea7
 	github.com/mitchellh/go-homedir v1.0.0
 	github.com/mitchellh/go-vnc v0.0.0-20150629162542-723ed9867aed
-	github.com/mitchellh/iochan v0.0.0-20150529224432-87b45ffd0e95
+	github.com/mitchellh/iochan v1.0.1-0.20190408094311-e9f5309a3061
 	github.com/mitchellh/mapstructure v0.0.0-20180111000720-b4575eea38cc
 	github.com/mitchellh/panicwrap v0.0.0-20170106182340-fce601fe5557
 	github.com/mitchellh/prefixedio v0.0.0-20151214002211-6e6954073784

go.sum

@@ -307,6 +307,8 @@ github.com/mitchellh/go-vnc v0.0.0-20150629162542-723ed9867aed h1:FI2NIv6fpef6BQ
 github.com/mitchellh/go-vnc v0.0.0-20150629162542-723ed9867aed/go.mod h1:3rdaFaCv4AyBgu5ALFM0+tSuHrBh6v692nyQe3ikrq0=
 github.com/mitchellh/iochan v0.0.0-20150529224432-87b45ffd0e95 h1:aHWVygBsLb+Kls/35B3tevL1hvDxZ0UklPA0BmhqTEk=
 github.com/mitchellh/iochan v0.0.0-20150529224432-87b45ffd0e95/go.mod h1:JwYml1nuB7xOzsp52dPpHFffvOCDupsG0QubkSMEySY=
+github.com/mitchellh/iochan v1.0.1-0.20190408094311-e9f5309a3061 h1:BSEloc+wp5WA/fu0jw5HBWOfoKLdvpqi38ZP22eNemg=
+github.com/mitchellh/iochan v1.0.1-0.20190408094311-e9f5309a3061/go.mod h1:JwYml1nuB7xOzsp52dPpHFffvOCDupsG0QubkSMEySY=
 github.com/mitchellh/mapstructure v0.0.0-20180111000720-b4575eea38cc h1:5T6hzGUO5OrL6MdYXYoLQtRWJDDgjdlOVBn9mIqGY1g=
 github.com/mitchellh/mapstructure v0.0.0-20180111000720-b4575eea38cc/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/mitchellh/panicwrap v0.0.0-20170106182340-fce601fe5557 h1:w1QuuAA2km2Hax+EPamrq5ZRBeaNv2vsjvgB4an0zoU=

packer/communicator.go

@@ -4,9 +4,7 @@ import (
 	"context"
 	"io"
 	"os"
-	"strings"
 	"sync"
-	"unicode"
 
 	"golang.org/x/sync/errgroup"
 
@@ -119,9 +117,9 @@ func (r *RemoteCmd) RunWithUi(ctx context.Context, c Communicator, ui Ui) error
 
 	// Loop and get all our output until done.
 	printFn := func(in io.Reader, out func(string)) error {
-		for output := range iochan.DelimReader(in, '\n') {
+		for output := range iochan.LineReader(in) {
 			if output != "" {
-				out(cleanOutputLine(output))
+				out(output)
 			}
 		}
 		return nil
@@ -176,19 +174,3 @@ func (r *RemoteCmd) initchan() {
 		}
 	})
 }
-
-// cleanOutputLine cleans up a line so that '\r' don't muck up the
-// UI output when we're reading from a remote command.
-func cleanOutputLine(line string) string {
-	// Trim surrounding whitespace
-	line = strings.TrimRightFunc(line, unicode.IsSpace)
-
-	// Trim up to the first carriage return, since that text would be
-	// lost anyways.
-	idx := strings.LastIndex(line, "\r")
-	if idx > -1 {
-		line = line[idx+1:]
-	}
-
-	return line
-}

vendor/github.com/mitchellh/iochan/go.mod

@@ -0,0 +1 @@
+module github.com/mitchellh/iochan

vendor/github.com/mitchellh/iochan/iochan.go

@@ -39,3 +39,25 @@ func DelimReader(r io.Reader, delim byte) <-chan string {
 
 	return ch
 }
+
+// LineReader takes an io.Reader and produces the contents of the reader on the
+// returned channel. Internally bufio.NewScanner is used, io.ScanLines parses
+// lines and returns them without carriage return. Scan can panic if the split
+// function returns too many empty tokens without advancing the input.
+//
+// The channel will be closed either by reaching the end of the input or an
+// error.
+func LineReader(r io.Reader) <-chan string {
+	ch := make(chan string)
+
+	go func() {
+		scanner := bufio.NewScanner(r)
+		defer close(ch)
+
+		for scanner.Scan() {
+			ch <- scanner.Text()
+		}
+	}()
+
+	return ch
+}