From 9d5c5bf7ab82159d9f0cb6936d0475a270c24862 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Sun, 4 Apr 2021 14:47:57 +0100
Subject: [PATCH] fs: add Options.NonDefault to read options which aren't at
 their default #5178

---
 fs/fs.go      | 17 +++++++++++++++++
 fs/fs_test.go | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/fs/fs.go b/fs/fs.go
index 4911a8c98..946a75ee0 100644
--- a/fs/fs.go
+++ b/fs/fs.go
@@ -140,6 +140,23 @@ func (os Options) Overridden(m *configmap.Map) configmap.Simple {
 	return overridden
 }
 
+// NonDefault discovers which config values aren't at their default
+func (os Options) NonDefault(m configmap.Getter) configmap.Simple {
+	var nonDefault = configmap.Simple{}
+	for i := range os {
+		opt := &os[i]
+		value, isSet := m.Get(opt.Name)
+		if !isSet {
+			continue
+		}
+		defaultValue := fmt.Sprint(opt.Default)
+		if value != defaultValue {
+			nonDefault.Set(opt.Name, value)
+		}
+	}
+	return nonDefault
+}
+
 // OptionVisibility controls whether the options are visible in the
 // configurator or the command line.
 type OptionVisibility byte
diff --git a/fs/fs_test.go b/fs/fs_test.go
index 4de8ba370..0ad09cf07 100644
--- a/fs/fs_test.go
+++ b/fs/fs_test.go
@@ -190,6 +190,43 @@ func TestOptionsGet(t *testing.T) {
 	assert.Nil(t, opt)
 }
 
+func TestOptionsOveridden(t *testing.T) {
+	m := configmap.New()
+	m1 := configmap.Simple{
+		"nounc":      "m1",
+		"copy_links": "m1",
+	}
+	m.AddGetter(m1, configmap.PriorityNormal)
+	m2 := configmap.Simple{
+		"nounc":            "m2",
+		"case_insensitive": "m2",
+	}
+	m.AddGetter(m2, configmap.PriorityConfig)
+	m3 := configmap.Simple{
+		"nounc": "m3",
+	}
+	m.AddGetter(m3, configmap.PriorityDefault)
+	got := testOptions.Overridden(m)
+	assert.Equal(t, configmap.Simple{
+		"copy_links": "m1",
+		"nounc":      "m1",
+	}, got)
+}
+
+func TestOptionsNonDefault(t *testing.T) {
+	m := configmap.Simple{}
+	got := testOptions.NonDefault(m)
+	assert.Equal(t, configmap.Simple{}, got)
+
+	m["case_insensitive"] = "false"
+	got = testOptions.NonDefault(m)
+	assert.Equal(t, configmap.Simple{}, got)
+
+	m["case_insensitive"] = "true"
+	got = testOptions.NonDefault(m)
+	assert.Equal(t, configmap.Simple{"case_insensitive": "true"}, got)
+}
+
 func TestOptionMarshalJSON(t *testing.T) {
 	out, err := json.MarshalIndent(&caseInsensitiveOption, "", "")
 	assert.NoError(t, err)