Clean up merge3 changes

cmd/config/internal/commands/merge3.go

@@ -5,7 +5,7 @@ package commands
 
 import (
 	"github.com/spf13/cobra"
-	"sigs.k8s.io/kustomize/cmd/config/cmddocs/commands"
+	"sigs.k8s.io/kustomize/cmd/config/internal/generateddocs/commands"
 	"sigs.k8s.io/kustomize/kyaml/kio/filters"
 )
 
@@ -36,17 +36,17 @@ func Merge3Command(name string) *cobra.Command {
 
 // Merge3Runner contains the run function
 type Merge3Runner struct {
-	Command     *cobra.Command
-	ancestor	string
-	fromDir		string
-	toDir		string
+	Command  *cobra.Command
+	ancestor string
+	fromDir  string
+	toDir    string
 }
 
 func (r *Merge3Runner) runE(c *cobra.Command, args []string) error {
 	err := filters.Merge3{
 		OriginalPath: r.ancestor,
-		UpdatedPath: r.fromDir,
-		DestPath: r.toDir,
+		UpdatedPath:  r.fromDir,
+		DestPath:     r.toDir,
 	}.Merge()
 	if err != nil {
 		return err

cmd/config/internal/commands/merge3_test.go

@@ -1,7 +1,8 @@
 // Copyright 2019 The Kubernetes Authors.
 // SPDX-License-Identifier: Apache-2.0
 
-package commands
+package commands_test
+
 
 import (
 	"io/ioutil"
@@ -233,4 +234,4 @@ spec:
 	if !assert.Empty(t, diffs.List()) {
 		t.FailNow()
 	}
-} 
+}

cmd/config/internal/generateddocs/commands/docs.go

@@ -136,6 +136,25 @@ For information on merge rules, run:
 var MergeExamples = `
     cat resources_and_patches.yaml | kustomize config merge > merged_resources.yaml`
 
+var Merge3Short = `[Alpha] Merge diff of Resource configuration files into a destination (3-way)`
+var Merge3Long = `
+[Alpha] Merge diff of Resource configuration files into a destination (3-way)
+
+Merge3 performs a 3-way merge by applying the diff between 2 sets of Resources to a 3rd set.
+
+Merge3 may be for rebasing changes to a forked set of configuration -- e.g. compute the difference between the original
+set of Resources that was forked and an updated set of those Resources, then apply that difference to the fork.
+
+If a field value differs between the ORIGINAL_DIR and UPDATED_DIR, the value from the UPDATED_DIR is taken and applied
+to the Resource in the DEST_DIR.
+
+For information on merge rules, run:
+
+	kustomize config docs-merge3
+`
+var Merge3Examples = `
+    kustomize config merge3 --ancestor a/ --from b/ --to c/`
+
 var RunFnsShort = `[Alpha] Reoncile config functions to Resources.`
 var RunFnsLong = `
 [Alpha] Reconcile config functions to Resources.