From 43f3914148a17d30754a20f808e775308c771d38 Mon Sep 17 00:00:00 2001
From: sriv <srikanth.ddit@gmail.com>
Date: Wed, 23 Sep 2020 08:50:34 +0530
Subject: [PATCH 1/3] enhance error message for circular references

Signed-off-by: sriv <srikanth.ddit@gmail.com>
---
 properties.go      |  7 ++++++-
 properties_test.go | 11 ++++++-----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/properties.go b/properties.go
index 6e350a2..a4e8b62 100644
--- a/properties.go
+++ b/properties.go
@@ -766,7 +766,12 @@ func expand(s string, keys []string, prefix, postfix string, values map[string]s
 
 		for _, k := range keys {
 			if key == k {
-				return "", fmt.Errorf("circular reference in %q", key + " = " + prefix + k + postfix)
+				var b strings.Builder
+				b.WriteString("circular reference in:\n")
+				for _, k1 := range keys {
+					fmt.Fprintf(&b, "%s=%s\n", k1, values[k1])
+				}
+				return "", fmt.Errorf(b.String())
 			}
 		}
 
diff --git a/properties_test.go b/properties_test.go
index ad68ef4..c5c9a09 100644
--- a/properties_test.go
+++ b/properties_test.go
@@ -134,8 +134,8 @@ var errorTests = []struct {
 	{"key\\u123", "invalid unicode literal"},
 
 	// circular references
-	{"key=${key}", "circular reference"},
-	{"key1=${key2}\nkey2=${key1}", "circular reference"},
+	{"key=${key}", "circular reference in:\nkey=${key}"},
+	{"key1=${key2}\nkey2=${key1}", "circular reference in:\nkey1=${key2}\nkey2=${key1}"},
 
 	// malformed expressions
 	{"key=${ke", "malformed expression"},
@@ -450,8 +450,8 @@ func TestComplex(t *testing.T) {
 func TestErrors(t *testing.T) {
 	for _, test := range errorTests {
 		_, err := Load([]byte(test.input), ISO_8859_1)
-		assert.Equal(t, err != nil, true, "want error")
-		assert.Equal(t, strings.Contains(err.Error(), test.msg), true)
+		assert.Equal(t, err != nil, true, fmt.Sprintf("want error: %s", test.input))
+		assert.Equal(t, strings.Contains(err.Error(), test.msg), true, fmt.Sprintf("expected %s, got %s", test.msg, err.Error()))
 	}
 }
 
@@ -796,7 +796,8 @@ func TestSetValue(t *testing.T) {
 func TestMustSet(t *testing.T) {
 	input := "key=${key}"
 	p := mustParse(t, input)
-	assert.Panic(t, func() { p.MustSet("key", "${key}") }, `circular reference in "key = \$\{key\}"`)
+	e := `circular reference in:\nkey=\$\{key\}`
+	assert.Panic(t, func() { p.MustSet("key", "${key}") }, e)
 }
 
 func TestWrite(t *testing.T) {

From 6055178460ad761402a3d84e80b8156b2552d857 Mon Sep 17 00:00:00 2001
From: sriv <srikanth.ddit@gmail.com>
Date: Wed, 23 Sep 2020 11:29:53 +0530
Subject: [PATCH 2/3] use regex to match properties in any order

---
 properties_test.go | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/properties_test.go b/properties_test.go
index c5c9a09..6969cf7 100644
--- a/properties_test.go
+++ b/properties_test.go
@@ -11,6 +11,7 @@ import (
 	"math"
 	"os"
 	"reflect"
+	"regexp"
 	"runtime"
 	"strings"
 	"testing"
@@ -134,8 +135,8 @@ var errorTests = []struct {
 	{"key\\u123", "invalid unicode literal"},
 
 	// circular references
-	{"key=${key}", "circular reference in:\nkey=${key}"},
-	{"key1=${key2}\nkey2=${key1}", "circular reference in:\nkey1=${key2}\nkey2=${key1}"},
+	{"key=${key}", `circular reference in:\nkey=\$\{key\}`},
+	{"key1=${key2}\nkey2=${key1}", `circular reference in:\n(key1=\$\{key2\}\nkey2=\$\{key1\}|key2=\$\{key1\}\nkey1=\$\{key2\})`},
 
 	// malformed expressions
 	{"key=${ke", "malformed expression"},
@@ -451,7 +452,8 @@ func TestErrors(t *testing.T) {
 	for _, test := range errorTests {
 		_, err := Load([]byte(test.input), ISO_8859_1)
 		assert.Equal(t, err != nil, true, fmt.Sprintf("want error: %s", test.input))
-		assert.Equal(t, strings.Contains(err.Error(), test.msg), true, fmt.Sprintf("expected %s, got %s", test.msg, err.Error()))
+		re := regexp.MustCompile(test.msg)
+		assert.Equal(t, re.MatchString(err.Error()), true, fmt.Sprintf("expected %s, got %s", test.msg, err.Error()))
 	}
 }
 

From 3c8ae351e57e13c69f9b2b55922df3e7cebcd75b Mon Sep 17 00:00:00 2001
From: sriv <srikanth.ddit@gmail.com>
Date: Wed, 23 Sep 2020 14:00:12 +0530
Subject: [PATCH 3/3] use bytes.Buffer, should work with older go versions

---
 properties.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/properties.go b/properties.go
index a4e8b62..0d0fc28 100644
--- a/properties.go
+++ b/properties.go
@@ -8,6 +8,7 @@ package properties
 // BUG(frank): Write() does not allow to configure the newline character. Therefore, on Windows LF is used.
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"log"
@@ -766,7 +767,7 @@ func expand(s string, keys []string, prefix, postfix string, values map[string]s
 
 		for _, k := range keys {
 			if key == k {
-				var b strings.Builder
+				var b bytes.Buffer
 				b.WriteString("circular reference in:\n")
 				for _, k1 := range keys {
 					fmt.Fprintf(&b, "%s=%s\n", k1, values[k1])