From b22b4801affac6acf61ade62b465392c6f09e93d Mon Sep 17 00:00:00 2001
From: Harry White <harry.white424@gmail.com>
Date: Mon, 28 Oct 2019 22:45:37 +1100
Subject: [PATCH] Return error with stderr value

To maintain existing behaviour when not capturing stdout and stderr
---
 pkg/commands/os.go | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pkg/commands/os.go b/pkg/commands/os.go
index b2fd42ec..22490b49 100644
--- a/pkg/commands/os.go
+++ b/pkg/commands/os.go
@@ -115,11 +115,12 @@ func sanitisedCommandOutput(output []byte, err error) (string, error) {
 	outputString := string(output)
 	if err != nil {
 		// errors like 'exit status 1' are not very useful so we'll create an error
-		// from the combined output
-		if outputString == "" {
-			return "", WrapError(err)
+		// from stderr if we got an ExitError
+		exitError, ok := err.(*exec.ExitError)
+		if ok {
+			return outputString, errors.New(string(exitError.Stderr))
 		}
-		return outputString, errors.New(outputString)
+		return "", WrapError(err)
 	}
 	return outputString, nil
 }