[syntax] Refactor YAML editing functionality (#411)

Replace the CLI's `yamlNode` type and methods with equivalents on
`syntax.YAMLNode`.

This is a bit duplicative of functionality already in the syntax
package, which allows consumers to edit syntax trees without knowledge
of the concrete syntax. However, this is the lowest-lift option for
refactoring this functionality with high confidence in the results. We
should replace the `YAMLNode` methods with higher-level methods that
are concrete-syntax-agnostic in the future.

Author: pgavlin

cmd/esc/cli/env_get.go

@@ -22,6 +22,7 @@ import (
 	"github.com/pulumi/esc"
 	"github.com/pulumi/esc/cmd/esc/cli/client"
 	"github.com/pulumi/esc/cmd/esc/cli/style"
+	"github.com/pulumi/esc/syntax/encoding"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/util/cmdutil"
 )
@@ -281,7 +282,7 @@ func (get *envGetCommand) getEnvironmentMember(
 	}
 
 	if len(path) != 0 && path[0] == "imports" {
-		node, _ := yamlNode{&docNode}.get(path)
+		node, _ := encoding.YAMLSyntax{Node: &docNode}.Get(path)
 		if node == nil {
 			return nil, nil
 		}
@@ -313,8 +314,8 @@ func (get *envGetCommand) getEnvironmentMember(
 	}
 
 	definitionYAML := ""
-	if valuesNode, ok := (yamlNode{&docNode}.get(resource.PropertyPath{"values"})); ok {
-		if node, _ := (yamlNode{valuesNode}.get(path)); node != nil {
+	if valuesNode, ok := (encoding.YAMLSyntax{Node: &docNode}.Get(resource.PropertyPath{"values"})); ok {
+		if node, _ := (encoding.YAMLSyntax{Node: valuesNode}.Get(path)); node != nil {
 			expr, ok := getEnvExpr(esc.Expr{Object: env.Exprs}, path)
 			if !ok {
 				return nil, fmt.Errorf("internal error: no expr for path %v", path)

cmd/esc/cli/env_rm.go

@@ -10,6 +10,7 @@ import (
 	"github.com/spf13/cobra"
 	"gopkg.in/yaml.v3"
 
+	"github.com/pulumi/esc/syntax/encoding"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/diag/colors"
 	pulumienv "github.com/pulumi/pulumi/sdk/v3/go/common/env"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
@@ -84,11 +85,11 @@ func newEnvRmCmd(env *envCommand) *cobra.Command {
 			if docNode.Kind != yaml.DocumentNode {
 				return nil
 			}
-			valuesNode, ok := yamlNode{&docNode}.get(resource.PropertyPath{"values"})
+			valuesNode, ok := encoding.YAMLSyntax{Node: &docNode}.Get(resource.PropertyPath{"values"})
 			if !ok {
 				return nil
 			}
-			err = yamlNode{valuesNode}.delete(nil, path)
+			err = encoding.YAMLSyntax{Node: valuesNode}.Delete(nil, path)
 			if err != nil {
 				return err
 			}

cmd/esc/cli/env_set.go

@@ -12,6 +12,7 @@ import (
 	"github.com/spf13/cobra"
 	"gopkg.in/yaml.v3"
 
+	"github.com/pulumi/esc/syntax/encoding"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
 )
@@ -107,18 +108,18 @@ func newEnvSetCmd(env *envCommand) *cobra.Command {
 			}
 
 			if path[0] == "imports" {
-				_, err = yamlNode{&docNode}.set(nil, path, yamlValue)
+				_, err = encoding.YAMLSyntax{Node: &docNode}.Set(nil, path, yamlValue)
 			} else {
-				valuesNode, ok := yamlNode{&docNode}.get(resource.PropertyPath{"values"})
+				valuesNode, ok := encoding.YAMLSyntax{Node: &docNode}.Get(resource.PropertyPath{"values"})
 				if !ok {
-					valuesNode, err = yamlNode{&docNode}.set(nil, resource.PropertyPath{"values"}, yaml.Node{
+					valuesNode, err = encoding.YAMLSyntax{Node: &docNode}.Set(nil, resource.PropertyPath{"values"}, yaml.Node{
 						Kind: yaml.MappingNode,
 					})
 					if err != nil {
 						return fmt.Errorf("internal error: %w", err)
 					}
 				}
-				_, err = yamlNode{valuesNode}.set(nil, path, yamlValue)
+				_, err = encoding.YAMLSyntax{Node: valuesNode}.Set(nil, path, yamlValue)
 			}
 			if err != nil {
 				return err
@@ -187,154 +188,3 @@ func looksLikeSecret(path resource.PropertyPath, n yaml.Node) bool {
 	return info.Entropy >= entropyThreshold ||
 		(info.Entropy >= (entropyThreshold/2) && entropyPerChar >= entropyPerCharThreshold)
 }
-
-type yamlNode struct {
-	*yaml.Node
-}
-
-func (n yamlNode) get(path resource.PropertyPath) (_ *yaml.Node, ok bool) {
-	if n.Kind == yaml.DocumentNode {
-		return yamlNode{n.Content[0]}.get(path)
-	}
-
-	if len(path) == 0 {
-		return n.Node, true
-	}
-
-	switch n.Kind {
-	case yaml.SequenceNode:
-		index, ok := path[0].(int)
-		if !ok || index < 0 || index >= len(n.Content) {
-			return nil, false
-		}
-		return yamlNode{n.Content[index]}.get(path[1:])
-	case yaml.MappingNode:
-		key, ok := path[0].(string)
-		if !ok {
-			return nil, false
-		}
-		for i := 0; i < len(n.Content); i += 2 {
-			keyNode, valueNode := n.Content[i], n.Content[i+1]
-			if keyNode.Value == key {
-				return yamlNode{valueNode}.get(path[1:])
-			}
-		}
-		return nil, false
-	default:
-		return nil, false
-	}
-}
-
-func (n yamlNode) set(prefix, path resource.PropertyPath, new yaml.Node) (*yaml.Node, error) {
-	if n.Kind == yaml.DocumentNode {
-		return yamlNode{n.Content[0]}.set(prefix, path, new)
-	}
-
-	if len(path) == 0 {
-		n.Content = new.Content
-		n.Kind = new.Kind
-		n.Tag = new.Tag
-		n.Value = new.Value
-		return n.Node, nil
-	}
-
-	prefix = append(prefix, path[0])
-	switch n.Kind {
-	case 0:
-		switch accessor := path[0].(type) {
-		case int:
-			n.Kind, n.Tag = yaml.SequenceNode, "!!seq"
-		case string:
-			n.Kind, n.Tag = yaml.MappingNode, "!!map"
-		default:
-			contract.Failf("unexpected accessor kind %T", accessor)
-			return nil, nil
-		}
-		return n.set(prefix[:len(prefix)-1], path, new)
-	case yaml.SequenceNode:
-		index, ok := path[0].(int)
-		if !ok {
-			return nil, fmt.Errorf("%v: key for an array must be an int", prefix)
-		}
-		if index < 0 || index > len(n.Content) {
-			return nil, fmt.Errorf("%v: array index out of range", prefix)
-		}
-		if index == len(n.Content) {
-			n.Content = append(n.Content, &yaml.Node{})
-		}
-		elem := n.Content[index]
-		return yamlNode{elem}.set(prefix, path[1:], new)
-	case yaml.MappingNode:
-		key, ok := path[0].(string)
-		if !ok {
-			return nil, fmt.Errorf("%v: key for a map must be a string", prefix)
-		}
-
-		var valueNode *yaml.Node
-		for i := 0; i < len(n.Content); i += 2 {
-			keyNode, value := n.Content[i], n.Content[i+1]
-			if keyNode.Value == key {
-				valueNode = value
-				break
-			}
-		}
-		if valueNode == nil {
-			n.Content = append(n.Content, &yaml.Node{
-				Kind:  yaml.ScalarNode,
-				Value: key,
-				Tag:   "!!str",
-			})
-			n.Content = append(n.Content, &yaml.Node{})
-			valueNode = n.Content[len(n.Content)-1]
-		}
-		return yamlNode{valueNode}.set(prefix, path[1:], new)
-	default:
-		return nil, fmt.Errorf("%v: expected an array or an object", prefix)
-	}
-}
-
-func (n yamlNode) delete(prefix, path resource.PropertyPath) error {
-	if n.Kind == yaml.DocumentNode {
-		return yamlNode{n.Content[0]}.delete(prefix, path)
-	}
-
-	prefix = append(prefix, path[0])
-	switch n.Kind {
-	case yaml.SequenceNode:
-		index, ok := path[0].(int)
-		if !ok {
-			return fmt.Errorf("%v: key for an array must be an int", prefix)
-		}
-		if index < 0 || index >= len(n.Content) {
-			return fmt.Errorf("%v: array index out of range", prefix)
-		}
-		if len(path) == 1 {
-			n.Content = append(n.Content[:index], n.Content[index+1:]...)
-			return nil
-		}
-		elem := n.Content[index]
-		return yamlNode{elem}.delete(prefix, path[1:])
-	case yaml.MappingNode:
-		key, ok := path[0].(string)
-		if !ok {
-			return fmt.Errorf("%v: key for a map must be a string", prefix)
-		}
-
-		i := 0
-		for ; i < len(n.Content); i += 2 {
-			if n.Content[i].Value == key {
-				break
-			}
-		}
-		if len(path) == 1 {
-			if i != len(n.Content) {
-				n.Content = append(n.Content[:i], n.Content[i+2:]...)
-			}
-			return nil
-		}
-		valueNode := n.Content[i+1]
-		return yamlNode{valueNode}.delete(prefix, path[1:])
-	default:
-		return fmt.Errorf("%v: expected an array or an object", prefix)
-	}
-}

syntax/encoding/testdata/yaml-edit/add-object-property/doc.yaml

@@ -0,0 +1,2 @@
+values:
+  foo: bar

syntax/encoding/testdata/yaml-edit/add-object-property/edits.yaml

@@ -0,0 +1,2 @@
+edits:
+  - values.bar: baz

syntax/encoding/testdata/yaml-edit/add-object-property/expected.yaml

@@ -0,0 +1,3 @@
+values:
+    foo: bar
+    bar: baz

syntax/encoding/testdata/yaml-edit/append-array-element/doc.yaml

@@ -0,0 +1,3 @@
+values:
+  array:
+    - hello

syntax/encoding/testdata/yaml-edit/append-array-element/edits.yaml

@@ -0,0 +1,2 @@
+edits:
+  - 'values.array[1]': world

syntax/encoding/testdata/yaml-edit/append-array-element/expected.yaml

@@ -0,0 +1,4 @@
+values:
+    array:
+        - hello
+        - world

syntax/encoding/testdata/yaml-edit/many/doc.yaml

@@ -0,0 +1,8 @@
+edits:
+  - 'object["foo"]': baz
+  - 'object["bar"]': qux
+  - 'array[0]': 1
+  - 'array[1].nested': 2
+  - '["dotted.property"]': [list, of, strings]
+  - 'environmentVariables': {HELLO: world}
+  - '["deeply.nested"].path.with.an["\"array[]\""][0]': neat

syntax/encoding/testdata/yaml-edit/many/edits.yaml

@@ -0,0 +1,18 @@
+object:
+    foo: baz
+    bar: qux
+array:
+    - 1
+    - nested: 2
+dotted.property:
+    - list
+    - of
+    - strings
+environmentVariables:
+    HELLO: world
+deeply.nested:
+    path:
+        with:
+            an:
+                '"array[]"':
+                    - neat

syntax/encoding/testdata/yaml-edit/many/expected.yaml

@@ -0,0 +1,3 @@
+values:
+  array:
+    - hello

syntax/encoding/testdata/yaml-edit/remove-array-element/doc.yaml

@@ -0,0 +1,2 @@
+edits:
+  - 'values.array[0]': null

syntax/encoding/testdata/yaml-edit/remove-array-element/edits.yaml

@@ -0,0 +1,2 @@
+values:
+    array: []

syntax/encoding/testdata/yaml-edit/remove-array-element/expected.yaml

@@ -0,0 +1,2 @@
+values:
+  foo: bar

syntax/encoding/testdata/yaml-edit/remove-object-property/doc.yaml

@@ -0,0 +1,2 @@
+edits:
+  - values.foo: null

syntax/encoding/testdata/yaml-edit/remove-object-property/edits.yaml

@@ -0,0 +1 @@
+values: {}

syntax/encoding/testdata/yaml-edit/remove-object-property/expected.yaml

@@ -0,0 +1,3 @@
+values:
+  array:
+    - hello

syntax/encoding/testdata/yaml-edit/replace-array-element/doc.yaml

@@ -0,0 +1,2 @@
+edits:
+  - 'values.array[0]': bonjour

syntax/encoding/testdata/yaml-edit/replace-array-element/edits.yaml

@@ -0,0 +1,3 @@
+values:
+    array:
+        - bonjour

syntax/encoding/testdata/yaml-edit/replace-array-element/expected.yaml

@@ -0,0 +1,2 @@
+values:
+  foo: bar

syntax/encoding/testdata/yaml-edit/replace-object-property/doc.yaml

@@ -0,0 +1,2 @@
+edits:
+  - values.foo: baz

syntax/encoding/testdata/yaml-edit/replace-object-property/edits.yaml

@@ -0,0 +1,2 @@
+values:
+    foo: baz