fix(fsrepo): deep merge when setting config

repo/common/common.go

@@ -54,3 +54,33 @@ func MapSetKV(v map[string]interface{}, key string, value interface{}) error {
 	}
 	return nil
 }
+
+// Merges the right map into the left map, recursively traversing child maps
+// until a non-map value is found
+func MapMergeDeep(left, right map[string]interface{}) map[string]interface{} {
+	// We want to alter a copy of the map, not the original
+	result := make(map[string]interface{})
+	for k, v := range left {
+		result[k] = v
+	}
+
+	for key, rightVal := range right {
+		// If right value is a map
+		if rightMap, ok := rightVal.(map[string]interface{}); ok {
+			// If key is in left
+			if leftVal, found := result[key]; found {
+				// If left value is also a map
+				if leftMap, ok := leftVal.(map[string]interface{}); ok {
+					// Merge nested map
+					result[key] = MapMergeDeep(leftMap, rightMap)
+					continue
+				}
+			}
+		}
+
+		// Otherwise set new value to result
+		result[key] = rightVal
+	}
+
+	return result
+}

repo/common/common_test.go

@@ -0,0 +1,132 @@
+package common
+
+import (
+	"testing"
+
+	"github.com/ipfs/go-ipfs/thirdparty/assert"
+)
+
+func TestMapMergeDeepReturnsNew(t *testing.T) {
+	leftMap := make(map[string]interface{})
+	leftMap["A"] = "Hello World"
+
+	rightMap := make(map[string]interface{})
+	rightMap["A"] = "Foo"
+
+	MapMergeDeep(leftMap, rightMap)
+
+	assert.True(leftMap["A"] == "Hello World", t, "MapMergeDeep should return a new map instance")
+}
+
+func TestMapMergeDeepNewKey(t *testing.T) {
+	leftMap := make(map[string]interface{})
+	leftMap["A"] = "Hello World"
+	/*
+		leftMap
+		{
+			A: "Hello World"
+		}
+	*/
+
+	rightMap := make(map[string]interface{})
+	rightMap["B"] = "Bar"
+	/*
+		rightMap
+		{
+			B: "Bar"
+		}
+	*/
+
+	result := MapMergeDeep(leftMap, rightMap)
+	/*
+		expected
+		{
+			A: "Hello World"
+			B: "Bar"
+		}
+	*/
+
+	assert.True(result["B"] == "Bar", t, "New keys in right map should exist in resulting map")
+}
+
+func TestMapMergeDeepRecursesOnMaps(t *testing.T) {
+	leftMapA := make(map[string]interface{})
+	leftMapA["B"] = "A value!"
+	leftMapA["C"] = "Another value!"
+
+	leftMap := make(map[string]interface{})
+	leftMap["A"] = leftMapA
+	/*
+		leftMap
+		{
+			A: {
+				B: "A value!"
+				C: "Another value!"
+			}
+		}
+	*/
+
+	rightMapA := make(map[string]interface{})
+	rightMapA["C"] = "A different value!"
+
+	rightMap := make(map[string]interface{})
+	rightMap["A"] = rightMapA
+	/*
+		rightMap
+		{
+			A: {
+				C: "A different value!"
+			}
+		}
+	*/
+
+	result := MapMergeDeep(leftMap, rightMap)
+	/*
+		expected
+		{
+			A: {
+				B: "A value!"
+				C: "A different value!"
+			}
+		}
+	*/
+
+	resultA := result["A"].(map[string]interface{})
+	assert.True(resultA["B"] == "A value!", t, "Unaltered values should not change")
+	assert.True(resultA["C"] == "A different value!", t, "Nested values should be altered")
+}
+
+func TestMapMergeDeepRightNotAMap(t *testing.T) {
+	leftMapA := make(map[string]interface{})
+	leftMapA["B"] = "A value!"
+
+	leftMap := make(map[string]interface{})
+	leftMap["A"] = leftMapA
+	/*
+		origMap
+		{
+			A: {
+				B: "A value!"
+			}
+		}
+	*/
+
+	rightMap := make(map[string]interface{})
+	rightMap["A"] = "Not a map!"
+	/*
+		newMap
+		{
+			A: "Not a map!"
+		}
+	*/
+
+	result := MapMergeDeep(leftMap, rightMap)
+	/*
+		expected
+		{
+			A: "Not a map!"
+		}
+	*/
+
+	assert.True(result["A"] == "Not a map!", t, "Right values that are not a map should be set on the result")
+}

repo/fsrepo/fsrepo.go

@@ -559,10 +559,8 @@ func (r *FSRepo) setConfigUnsynced(updated *config.Config) error {
 	if err != nil {
 		return err
 	}
-	for k, v := range m {
-		mapconf[k] = v
-	}
-	if err := serialize.WriteConfigFile(configFilename, mapconf); err != nil {
+	mergedMap := common.MapMergeDeep(mapconf, m)
+	if err := serialize.WriteConfigFile(configFilename, mergedMap); err != nil {
 		return err
 	}
 	// Do not use `*r.config = ...`. This will modify the *shared* config

test/sharness/t0250-files-api.sh

@@ -876,7 +876,7 @@ test_expect_success "set up automatic sharding/unsharding data" '
 '
 
 # TODO: This does not need to report an error https://github.com/ipfs/go-ipfs/issues/8088
-test_expect_failure "reset automatic sharding" '
+test_expect_success "reset automatic sharding" '
   ipfs config --json Internal.UnixFSShardingSizeThreshold null
 '