From 546865e1ee593e4853aaa9835abb37777878052d Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 8 Sep 2014 20:56:18 -0700
Subject: [PATCH] command: make sure errors from flag go to UI [GH-269]

---
 CHANGELOG.md    |  1 +
 command/meta.go | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index db03ab0bf..286a86238 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ BUG FIXES:
   * core: Fix certain syntax of configuration that could cause hang. [GH-261]
   * core: `-no-color` flag properly disables color. [GH-250]
   * core: "~" is expanded in `-var-file` flags. [GH-273]
+  * core: Errors with tfvars are shown in console. [GH-269]
   * providers/aws: Refreshing EIP from pre-0.2 state file won't error. [GH-258]
   * providers/google: Attaching a disk source (not an image) works
       properly. [GH-254]
diff --git a/command/meta.go b/command/meta.go
index f5922c589..fea12a095 100644
--- a/command/meta.go
+++ b/command/meta.go
@@ -1,8 +1,10 @@
 package command
 
 import (
+	"bufio"
 	"flag"
 	"fmt"
+	"io"
 	"math/rand"
 	"os"
 
@@ -137,6 +139,19 @@ func (m *Meta) flagSet(n string) *flag.FlagSet {
 		f.Var((*FlagVarFile)(&m.autoVariables), m.autoKey, "variable file")
 	}
 
+	// Create an io.Writer that writes to our Ui properly for errors.
+	// This is kind of a hack, but it does the job. Basically: create
+	// a pipe, use a scanner to break it into lines, and output each line
+	// to the UI. Do this forever.
+	errR, errW := io.Pipe()
+	errScanner := bufio.NewScanner(errR)
+	go func() {
+		for errScanner.Scan() {
+			m.Ui.Error(errScanner.Text())
+		}
+	}()
+	f.SetOutput(errW)
+
 	return f
 }