From 885e4cde81663537437e119067f9058c6d342ba0 Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Mon, 18 Dec 2017 11:38:51 -0500
Subject: [PATCH] don't loop indefinitely in confirm method

Only check for input twice in the meta.confirm method. This prevents an
errant newline from aborting the run while allowing Terraform to exit if
there is no input available. We don't just check for a tty, since we
still rely on being able to pipe input in for testing.

Remove the redundant confirmation loops in the migration code, and only
use the confirm method.
---
 command/meta.go                 |  4 +++-
 command/meta_backend_migrate.go | 33 ++-------------------------------
 2 files changed, 5 insertions(+), 32 deletions(-)

diff --git a/command/meta.go b/command/meta.go
index 27f7765f9..04c757497 100644
--- a/command/meta.go
+++ b/command/meta.go
@@ -476,7 +476,8 @@ func (m *Meta) confirm(opts *terraform.InputOpts) (bool, error) {
 	if !m.Input() {
 		return false, errors.New("input is disabled")
 	}
-	for {
+
+	for i := 0; i < 2; i++ {
 		v, err := m.UIInput().Input(opts)
 		if err != nil {
 			return false, fmt.Errorf(
@@ -490,6 +491,7 @@ func (m *Meta) confirm(opts *terraform.InputOpts) (bool, error) {
 			return true, nil
 		}
 	}
+	return false, nil
 }
 
 // showDiagnostics displays error and warning messages in the UI.
diff --git a/command/meta_backend_migrate.go b/command/meta_backend_migrate.go
index 552d70887..21c33d66d 100644
--- a/command/meta_backend_migrate.go
+++ b/command/meta_backend_migrate.go
@@ -346,22 +346,7 @@ func (m *Meta) backendMigrateEmptyConfirm(one, two state.State, opts *backendMig
 			opts.OneType, opts.TwoType),
 	}
 
-	// Confirm with the user that the copy should occur
-	for {
-		v, err := m.UIInput().Input(inputOpts)
-		if err != nil {
-			return false, fmt.Errorf(
-				"Error asking for state copy action: %s", err)
-		}
-
-		switch strings.ToLower(v) {
-		case "no":
-			return false, nil
-
-		case "yes":
-			return true, nil
-		}
-	}
+	return m.confirm(inputOpts)
 }
 
 func (m *Meta) backendMigrateNonEmptyConfirm(
@@ -410,21 +395,7 @@ func (m *Meta) backendMigrateNonEmptyConfirm(
 	}
 
 	// Confirm with the user that the copy should occur
-	for {
-		v, err := m.UIInput().Input(inputOpts)
-		if err != nil {
-			return false, fmt.Errorf(
-				"Error asking for state copy action: %s", err)
-		}
-
-		switch strings.ToLower(v) {
-		case "no":
-			return false, nil
-
-		case "yes":
-			return true, nil
-		}
-	}
+	return m.confirm(inputOpts)
 }
 
 type backendMigrateOpts struct {