From 96207f342c311dbcc0c2bb384cfa6b2815be53f3 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 10 Mar 2021 11:58:23 +0000
Subject: [PATCH] configmap: add consistent String() method to configmap.Simple
 #4996

---
 fs/config/configmap/configmap.go      | 33 +++++++++++++++++++++++++++
 fs/config/configmap/configmap_test.go | 24 +++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/fs/config/configmap/configmap.go b/fs/config/configmap/configmap.go
index 2d1267a22..fa323e1c1 100644
--- a/fs/config/configmap/configmap.go
+++ b/fs/config/configmap/configmap.go
@@ -1,6 +1,11 @@
 // Package configmap provides an abstraction for reading and writing config
 package configmap
 
+import (
+	"sort"
+	"strings"
+)
+
 // Getter provides an interface to get config items
 type Getter interface {
 	// Get should get an item with the key passed in and return
@@ -84,3 +89,31 @@ func (c Simple) Get(key string) (value string, ok bool) {
 func (c Simple) Set(key, value string) {
 	c[key] = value
 }
+
+// String the map value the same way the config parser does, but with
+// sorted keys for reproducability.
+func (c Simple) String() string {
+	var ks = make([]string, 0, len(c))
+	for k := range c {
+		ks = append(ks, k)
+	}
+	sort.Strings(ks)
+	var out strings.Builder
+	for _, k := range ks {
+		if out.Len() > 0 {
+			out.WriteRune(',')
+		}
+		out.WriteString(k)
+		out.WriteRune('=')
+		out.WriteRune('\'')
+		for _, ch := range c[k] {
+			out.WriteRune(ch)
+			// Escape ' as ''
+			if ch == '\'' {
+				out.WriteRune(ch)
+			}
+		}
+		out.WriteRune('\'')
+	}
+	return out.String()
+}
diff --git a/fs/config/configmap/configmap_test.go b/fs/config/configmap/configmap_test.go
index 08ef4ec52..90b70a4bf 100644
--- a/fs/config/configmap/configmap_test.go
+++ b/fs/config/configmap/configmap_test.go
@@ -89,3 +89,27 @@ func TestConfigMapSet(t *testing.T) {
 		"config2": "potato",
 	}, m2)
 }
+
+func TestSimpleString(t *testing.T) {
+	// Basic
+	assert.Equal(t, "", Simple(nil).String())
+	assert.Equal(t, "", Simple{}.String())
+	assert.Equal(t, "config1='one'", Simple{
+		"config1": "one",
+	}.String())
+
+	// Check ordering
+	assert.Equal(t, "config1='one',config2='two',config3='three',config4='four',config5='five'", Simple{
+		"config5": "five",
+		"config4": "four",
+		"config3": "three",
+		"config2": "two",
+		"config1": "one",
+	}.String())
+
+	// Check escaping
+	assert.Equal(t, "apple='',config1='o''n''e'", Simple{
+		"config1": "o'n'e",
+		"apple":   "",
+	}.String())
+}