Aliases!

examples/merge-anchor.yml

@@ -0,0 +1,17 @@
+foo: &foo
+  a: original
+  thing: coolasdf
+
+bar: &bar
+  b: 2
+
+
+overrideA:
+  <<: [*foo,*bar]
+  a: vanilla
+  c: 3
+
+foobar:
+  <<: *foo
+  thing: ice
+  c: 3

pkg/yqlib/data_navigator.go

@@ -96,7 +96,7 @@ func (n *navigator) Delete(rootNode *yaml.Node, path []string) error {
 			// need to delete in reverse - otherwise the matching indexes
 			// become incorrect.
 			matchingIndices := make([]int, 0)
-			_, errorVisiting := n.visitMatchingEntries(nodeToUpdate.Content, lastBit, func(indexInMap int) error {
+			_, errorVisiting := n.visitMatchingEntries(nodeToUpdate.Content, lastBit, func(matchingNode []*yaml.Node, indexInMap int) error {
 				matchingIndices = append(matchingIndices, indexInMap)
 				n.log.Debug("matchingIndices %v", indexInMap)
 				return nil
@@ -153,6 +153,9 @@ func (n *navigator) GuessKind(tail []string, guess yaml.Kind) yaml.Kind {
 		n.log.Debug("guess was an alias, okey doke.")
 		return guess
 	}
+	n.log.Debug("forcing a mapping node")
+	n.log.Debug("yaml.SequenceNode ?", guess == yaml.SequenceNode)
+	n.log.Debug("yaml.ScalarNode ?", guess == yaml.ScalarNode)
 	return yaml.MappingNode
 }
 
@@ -221,9 +224,9 @@ func (n *navigator) splatMap(value *yaml.Node, tail []string, visitor VisitorFn)
 }
 
 func (n *navigator) recurseMap(value *yaml.Node, head string, tail []string, visitor VisitorFn) error {
-	visited, errorVisiting := n.visitMatchingEntries(value.Content, head, func(indexInMap int) error {
+	visited, errorVisiting := n.visitMatchingEntries(value.Content, head, func(contents []*yaml.Node, indexInMap int) error {
-		value.Content[indexInMap+1] = n.getOrReplace(value.Content[indexInMap+1], n.GuessKind(tail, value.Content[indexInMap+1].Kind))
+		contents[indexInMap+1] = n.getOrReplace(contents[indexInMap+1], n.GuessKind(tail, contents[indexInMap+1].Kind))
-		return n.Visit(value.Content[indexInMap+1], tail, visitor)
+		return n.Visit(contents[indexInMap+1], tail, visitor)
 	})
 
 	if errorVisiting != nil {
@@ -242,18 +245,36 @@ func (n *navigator) recurseMap(value *yaml.Node, head string, tail []string, vis
 	return n.Visit(&mapEntryValue, tail, visitor)
 }
 
-type mapVisitorFn func(int) error
+// need to pass the node in, as it may be aliased
+type mapVisitorFn func([]*yaml.Node, int) error
 
 func (n *navigator) visitMatchingEntries(contents []*yaml.Node, key string, visit mapVisitorFn) (bool, error) {
 	visited := false
-
+	n.log.Debug("visitMatchingEntries %v in %v", key, contents)
 	// value.Content is a concatenated array of key, value,
 	// so keys are in the even indexes, values in odd.
-	for index := 0; index < len(contents); index = index + 2 {
+	// merge aliases are defined first, but we only want to traverse them
+	// if we dont find a match on this node first.
+	for index := len(contents) - 2; index >= 0; index = index - 2 {
 		content := contents[index]
-		n.log.Debug("index %v, checking %v", index, content.Value))
+		n.log.Debug("index %v, checking %v, %v", index, content.Value, content.Tag)
+
+		// only visit aliases if we didn't find a match in this object.
+		if n.followAliases && !visited && contents[index+1].Kind == yaml.AliasNode {
+			valueNode := contents[index+1]
+
+			n.log.Debug("need to visit the alias too")
+			n.DebugNode(valueNode)
+			visitedAlias, errorInAlias := n.visitMatchingEntries(valueNode.Alias.Content, key, visit)
+			if errorInAlias != nil {
+				return false, errorInAlias
+			}
+			visited = visited || visitedAlias
+		}
+
 		if n.matchesKey(key, content.Value) {
-			errorVisiting := visit(index)
+			n.log.Debug("found a match! %v", content.Value)
+			errorVisiting := visit(contents, index)
 			if errorVisiting != nil {
 				return visited, errorVisiting
 			}

test.yml

@@ -1,2 +1,4 @@
-a: apple
+foo: &foo
-c: cat
+  a: 1
+
+foobar: *foo

yq.go

@@ -79,7 +79,7 @@ func newCommandCLI() *cobra.Command {
 		createPrefixCmd(),
 		createDeleteCmd(),
 		createNewCmd(),
-		// createMergeCmd(),
+		createMergeCmd(),
 	)
 	rootCmd.SetOutput(os.Stdout)
 
@@ -211,36 +211,36 @@ Note that you can give a create script to perform more sophisticated yaml. This
 	return cmdNew
 }
 
-// func createMergeCmd() *cobra.Command {
+func createMergeCmd() *cobra.Command {
-// 	var cmdMerge = &cobra.Command{
+	var cmdMerge = &cobra.Command{
-// 		Use:     "merge [initial_yaml_file] [additional_yaml_file]...",
+		Use:     "merge [initial_yaml_file] [additional_yaml_file]...",
-// 		Aliases: []string{"m"},
+		Aliases: []string{"m"},
-// 		Short:   "yq m [--inplace/-i] [--doc/-d index] [--overwrite/-x] [--append/-a] sample.yaml sample2.yaml",
+		Short:   "yq m [--inplace/-i] [--doc/-d index] [--overwrite/-x] [--append/-a] sample.yaml sample2.yaml",
-// 		Example: `
+		Example: `
-// yq merge things.yaml other.yaml
+yq merge things.yaml other.yaml
-// yq merge --inplace things.yaml other.yaml
+yq merge --inplace things.yaml other.yaml
-// yq m -i things.yaml other.yaml
+yq m -i things.yaml other.yaml
-// yq m --overwrite things.yaml other.yaml
+yq m --overwrite things.yaml other.yaml
-// yq m -i -x things.yaml other.yaml
+yq m -i -x things.yaml other.yaml
-// yq m -i -a things.yaml other.yaml
+yq m -i -a things.yaml other.yaml
-//       `,
+      `,
-// 		Long: `Updates the yaml file by adding/updating the path(s) and value(s) from additional yaml file(s).
+		Long: `Updates the yaml file by adding/updating the path(s) and value(s) from additional yaml file(s).
-// Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.
+Outputs to STDOUT unless the inplace flag is used, in which case the file is updated instead.
 
-// If overwrite flag is set then existing values will be overwritten using the values from each additional yaml file.
+If overwrite flag is set then existing values will be overwritten using the values from each additional yaml file.
-// If append flag is set then existing arrays will be merged with the arrays from each additional yaml file.
+If append flag is set then existing arrays will be merged with the arrays from each additional yaml file.
 
-// Note that if you set both flags only overwrite will take effect.
+Note that if you set both flags only overwrite will take effect.
-// `,
+`,
-// 		RunE: mergeProperties,
+		RunE: mergeProperties,
-// 	}
+	}
-// 	cmdMerge.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
+	cmdMerge.PersistentFlags().BoolVarP(&writeInplace, "inplace", "i", false, "update the yaml file inplace")
-// 	cmdMerge.PersistentFlags().BoolVarP(&overwriteFlag, "overwrite", "x", false, "update the yaml file by overwriting existing values")
+	// cmdMerge.PersistentFlags().BoolVarP(&overwriteFlag, "overwrite", "x", false, "update the yaml file by overwriting existing values")
-// 	cmdMerge.PersistentFlags().BoolVarP(&appendFlag, "append", "a", false, "update the yaml file by appending array values")
+	// cmdMerge.PersistentFlags().BoolVarP(&appendFlag, "append", "a", false, "update the yaml file by appending array values")
-// 	cmdMerge.PersistentFlags().BoolVarP(&allowEmptyFlag, "allow-empty", "e", false, "allow empty yaml files")
+	// cmdMerge.PersistentFlags().BoolVarP(&allowEmptyFlag, "allow-empty", "e", false, "allow empty yaml files")
-// 	cmdMerge.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number (0 based, * for all documents)")
+	cmdMerge.PersistentFlags().StringVarP(&docIndex, "doc", "d", "0", "process document index number (0 based, * for all documents)")
-// 	return cmdMerge
+	return cmdMerge
-// }
+}
 
 func readProperty(cmd *cobra.Command, args []string) error {
 	var path = ""
@@ -397,6 +397,11 @@ func writeProperty(cmd *cobra.Command, args []string) error {
 	return updateDoc(args[0], updateCommands, cmd.OutOrStdout())
 }
 
+func mergeProperties(cmd *cobra.Command, args []string) error {
+	// first generate update commands from the file
+	return nil
+}
+
 func newProperty(cmd *cobra.Command, args []string) error {
 	var updateCommands, updateCommandsError = readUpdateCommands(args, 2, "Must provide <path_to_update> <value>")
 	if updateCommandsError != nil {