mirror of https://github.com/databricks/cli.git
Function to merge two instances of `config.Value` (#938)
## Changes Semantics for merging two instances of `config.Value`: * Merging x with nil or nil with x always yields x * Merging maps a and b means entries from map b take precedence * Merging sequences a and b means concatenating them These are the same semantics that we use today when calling into mergo in `bundle/config`. ## Tests Unit tests pass.
This commit is contained in:
Pieter Noordhuis
GitHub
parent
401ae3dc99
commit
8e1156edbd
|
|
@ -0,0 +1,98 @@
|
|||
package merge
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
|
||||
"github.com/databricks/cli/libs/config"
|
||||
)
|
||||
|
||||
// Merge recursively merges the specified values.
|
||||
//
|
||||
// Semantics are as follows:
|
||||
// * Merging x with nil or nil with x always yields x.
|
||||
// * Merging maps a and b means entries from map b take precedence.
|
||||
// * Merging sequences a and b means concatenating them.
|
||||
func Merge(a, b config.Value) (config.Value, error) {
|
||||
return merge(a, b)
|
||||
}
|
||||
|
||||
func merge(a, b config.Value) (config.Value, error) {
|
||||
ak := a.Kind()
|
||||
bk := b.Kind()
|
||||
|
||||
// If a is nil, return b.
|
||||
if ak == config.KindNil {
|
||||
return b, nil
|
||||
}
|
||||
|
||||
// If b is nil, return a.
|
||||
if bk == config.KindNil {
|
||||
return a, nil
|
||||
}
|
||||
|
||||
// Call the appropriate merge function based on the kind of a and b.
|
||||
switch ak {
|
||||
case config.KindMap:
|
||||
if bk != config.KindMap {
|
||||
return config.NilValue, fmt.Errorf("cannot merge map with %s", bk)
|
||||
}
|
||||
return mergeMap(a, b)
|
||||
case config.KindSequence:
|
||||
if bk != config.KindSequence {
|
||||
return config.NilValue, fmt.Errorf("cannot merge sequence with %s", bk)
|
||||
}
|
||||
return mergeSequence(a, b)
|
||||
default:
|
||||
if ak != bk {
|
||||
return config.NilValue, fmt.Errorf("cannot merge %s with %s", ak, bk)
|
||||
}
|
||||
return mergePrimitive(a, b)
|
||||
}
|
||||
}
|
||||
|
||||
func mergeMap(a, b config.Value) (config.Value, error) {
|
||||
out := make(map[string]config.Value)
|
||||
am := a.MustMap()
|
||||
bm := b.MustMap()
|
||||
|
||||
// Add the values from a into the output map.
|
||||
for k, v := range am {
|
||||
out[k] = v
|
||||
}
|
||||
|
||||
// Merge the values from b into the output map.
|
||||
for k, v := range bm {
|
||||
if _, ok := out[k]; ok {
|
||||
// If the key already exists, merge the values.
|
||||
merged, err := merge(out[k], v)
|
||||
if err != nil {
|
||||
return config.NilValue, err
|
||||
}
|
||||
out[k] = merged
|
||||
} else {
|
||||
// Otherwise, just set the value.
|
||||
out[k] = v
|
||||
}
|
||||
}
|
||||
|
||||
// Preserve the location of the first value.
|
||||
return config.NewValue(out, a.Location()), nil
|
||||
}
|
||||
|
||||
func mergeSequence(a, b config.Value) (config.Value, error) {
|
||||
as := a.MustSequence()
|
||||
bs := b.MustSequence()
|
||||
|
||||
// Merging sequences means concatenating them.
|
||||
out := make([]config.Value, len(as)+len(bs))
|
||||
copy(out[:], as)
|
||||
copy(out[len(as):], bs)
|
||||
|
||||
// Preserve the location of the first value.
|
||||
return config.NewValue(out, a.Location()), nil
|
||||
}
|
||||
|
||||
func mergePrimitive(a, b config.Value) (config.Value, error) {
|
||||
// Merging primitive values means using the incoming value.
|
||||
return b, nil
|
||||
}
|
||||
|
|
@ -0,0 +1,207 @@
|
|||
package merge
|
||||
|
||||
import (
|
||||
"testing"
|
||||
|
||||
"github.com/databricks/cli/libs/config"
|
||||
"github.com/stretchr/testify/assert"
|
||||
)
|
||||
|
||||
func TestMergeMaps(t *testing.T) {
|
||||
v1 := config.V(map[string]config.Value{
|
||||
"foo": config.V("bar"),
|
||||
"bar": config.V("baz"),
|
||||
})
|
||||
|
||||
v2 := config.V(map[string]config.Value{
|
||||
"bar": config.V("qux"),
|
||||
"qux": config.V("foo"),
|
||||
})
|
||||
|
||||
// Merge v2 into v1.
|
||||
{
|
||||
out, err := Merge(v1, v2)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, map[string]any{
|
||||
"foo": "bar",
|
||||
"bar": "qux",
|
||||
"qux": "foo",
|
||||
}, out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v1 into v2.
|
||||
{
|
||||
out, err := Merge(v2, v1)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, map[string]any{
|
||||
"foo": "bar",
|
||||
"bar": "baz",
|
||||
"qux": "foo",
|
||||
}, out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergeMapsNil(t *testing.T) {
|
||||
v := config.V(map[string]config.Value{
|
||||
"foo": config.V("bar"),
|
||||
})
|
||||
|
||||
// Merge nil into v.
|
||||
{
|
||||
out, err := Merge(v, config.NilValue)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, map[string]any{
|
||||
"foo": "bar",
|
||||
}, out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v into nil.
|
||||
{
|
||||
out, err := Merge(config.NilValue, v)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, map[string]any{
|
||||
"foo": "bar",
|
||||
}, out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergeMapsError(t *testing.T) {
|
||||
v := config.V(map[string]config.Value{
|
||||
"foo": config.V("bar"),
|
||||
})
|
||||
|
||||
other := config.V("string")
|
||||
|
||||
// Merge a string into v.
|
||||
{
|
||||
out, err := Merge(v, other)
|
||||
assert.EqualError(t, err, "cannot merge map with string")
|
||||
assert.Equal(t, config.NilValue, out)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergeSequences(t *testing.T) {
|
||||
v1 := config.V([]config.Value{
|
||||
config.V("bar"),
|
||||
config.V("baz"),
|
||||
})
|
||||
|
||||
v2 := config.V([]config.Value{
|
||||
config.V("qux"),
|
||||
config.V("foo"),
|
||||
})
|
||||
|
||||
// Merge v2 into v1.
|
||||
{
|
||||
out, err := Merge(v1, v2)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, []any{
|
||||
"bar",
|
||||
"baz",
|
||||
"qux",
|
||||
"foo",
|
||||
}, out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v1 into v2.
|
||||
{
|
||||
out, err := Merge(v2, v1)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, []any{
|
||||
"qux",
|
||||
"foo",
|
||||
"bar",
|
||||
"baz",
|
||||
}, out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergeSequencesNil(t *testing.T) {
|
||||
v := config.V([]config.Value{
|
||||
config.V("bar"),
|
||||
})
|
||||
|
||||
// Merge nil into v.
|
||||
{
|
||||
out, err := Merge(v, config.NilValue)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, []any{
|
||||
"bar",
|
||||
}, out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v into nil.
|
||||
{
|
||||
out, err := Merge(config.NilValue, v)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, []any{
|
||||
"bar",
|
||||
}, out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergeSequencesError(t *testing.T) {
|
||||
v := config.V([]config.Value{
|
||||
config.V("bar"),
|
||||
})
|
||||
|
||||
other := config.V("string")
|
||||
|
||||
// Merge a string into v.
|
||||
{
|
||||
out, err := Merge(v, other)
|
||||
assert.EqualError(t, err, "cannot merge sequence with string")
|
||||
assert.Equal(t, config.NilValue, out)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergePrimitives(t *testing.T) {
|
||||
v1 := config.V("bar")
|
||||
v2 := config.V("baz")
|
||||
|
||||
// Merge v2 into v1.
|
||||
{
|
||||
out, err := Merge(v1, v2)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, "baz", out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v1 into v2.
|
||||
{
|
||||
out, err := Merge(v2, v1)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, "bar", out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergePrimitivesNil(t *testing.T) {
|
||||
v := config.V("bar")
|
||||
|
||||
// Merge nil into v.
|
||||
{
|
||||
out, err := Merge(v, config.NilValue)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, "bar", out.AsAny())
|
||||
}
|
||||
|
||||
// Merge v into nil.
|
||||
{
|
||||
out, err := Merge(config.NilValue, v)
|
||||
assert.NoError(t, err)
|
||||
assert.Equal(t, "bar", out.AsAny())
|
||||
}
|
||||
}
|
||||
|
||||
func TestMergePrimitivesError(t *testing.T) {
|
||||
v := config.V("bar")
|
||||
other := config.V(map[string]config.Value{
|
||||
"foo": config.V("bar"),
|
||||
})
|
||||
|
||||
// Merge a map into v.
|
||||
{
|
||||
out, err := Merge(v, other)
|
||||
assert.EqualError(t, err, "cannot merge string with map")
|
||||
assert.Equal(t, config.NilValue, out)
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue