Do not emit warning on YAML anchor blocks (#1354)

## Changes
In 0.217.0 we started to emit warning on unknown fields in YAML
configuration but wrongly considered YAML anchor blocks as unknown
field.

This PR fixes this by skipping normalising of YAML blocks.

## Tests
Added regression tests

bundle/tests/loader.go

@@ -7,6 +7,7 @@ import (
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config/mutator"
 	"github.com/databricks/cli/bundle/phases"
+	"github.com/databricks/cli/libs/diag"
 	"github.com/stretchr/testify/require"
 )
 
@@ -20,9 +21,18 @@ func load(t *testing.T, path string) *bundle.Bundle {
 }
 
 func loadTarget(t *testing.T, path, env string) *bundle.Bundle {
+	b, diags := loadTargetWithDiags(path, env)
+	require.NoError(t, diags.Error())
+	return b
+}
+
+func loadTargetWithDiags(path, env string) (*bundle.Bundle, diag.Diagnostics) {
 	ctx := context.Background()
 	b, err := bundle.Load(ctx, path)
-	require.NoError(t, err)
+	if err != nil {
+		return nil, diag.FromErr(err)
+	}
+
 	diags := bundle.Apply(ctx, b, bundle.Seq(
 		phases.LoadNamedTarget(env),
 		mutator.RewriteSyncPaths(),
@@ -30,6 +40,5 @@ func loadTarget(t *testing.T, path, env string) *bundle.Bundle {
 		mutator.MergeJobTasks(),
 		mutator.MergePipelineClusters(),
 	))
-	require.NoError(t, diags.Error())
+	return b, diags
-	return b
 }

bundle/tests/yaml_anchors_separate_block/databricks.yml

@@ -0,0 +1,15 @@
+bundle:
+  name: yaml_anchors_separate_block
+
+tags: &custom_tags
+  Tag1: "Value1"
+  Tag2: "Value2"
+  Tag3: "Value3"
+
+resources:
+  jobs:
+    my_job:
+      tasks:
+      - task_key: yaml_anchors_separate_block
+      tags:
+        <<: *custom_tags

bundle/tests/yaml_anchors_test.go

@@ -19,6 +19,18 @@ func TestYAMLAnchors(t *testing.T) {
 	require.NotNil(t, t0)
 	require.NotNil(t, t1)
 
+	require.NotNil(t, t0.NewCluster)
+	require.NotNil(t, t1.NewCluster)
 	assert.Equal(t, "10.4.x-scala2.12", t0.NewCluster.SparkVersion)
 	assert.Equal(t, "10.4.x-scala2.12", t1.NewCluster.SparkVersion)
 }
+
+func TestYAMLAnchorsNoWarnings(t *testing.T) {
+	_, diags := loadTargetWithDiags("./yaml_anchors", "default")
+	assert.Empty(t, diags)
+}
+
+func TestYAMLAnchorsSeparateBlockNoWarnings(t *testing.T) {
+	_, diags := loadTargetWithDiags("./yaml_anchors_separate_block", "default")
+	assert.Empty(t, diags)
+}

libs/dyn/convert/normalize.go

@@ -89,14 +89,17 @@ func (n normalizeOptions) normalizeStruct(typ reflect.Type, src dyn.Value, seen
 		for _, pair := range src.MustMap().Pairs() {
 			pk := pair.Key
 			pv := pair.Value
+
 			index, ok := info.Fields[pk.MustString()]
 			if !ok {
+				if !pv.IsAnchor() {
 					diags = diags.Append(diag.Diagnostic{
 						Severity: diag.Warning,
 						Summary:  fmt.Sprintf("unknown field: %s", pk.MustString()),
 						Location: pk.Location(),
 						Path:     path,
 					})
+				}
 				continue
 			}
 

libs/dyn/convert/normalize_test.go

@@ -659,3 +659,23 @@ func TestNormalizeFloatError(t *testing.T) {
 		Path:     dyn.EmptyPath,
 	}, err[0])
 }
+
+func TestNormalizeAnchors(t *testing.T) {
+	type Tmp struct {
+		Foo string `json:"foo"`
+	}
+
+	var typ Tmp
+	vin := dyn.V(map[string]dyn.Value{
+		"foo":    dyn.V("bar"),
+		"anchor": dyn.V("anchor").MarkAnchor(),
+	})
+
+	vout, err := Normalize(typ, vin)
+	assert.Len(t, err, 0)
+
+	// The field that can be mapped to the struct field is retained.
+	assert.Equal(t, map[string]any{
+		"foo": "bar",
+	}, vout.AsAny())
+}