Buildozer new command: copy rule

buildozer/README.md

@@ -117,6 +117,8 @@ Buildozer supports the following commands(`'command args'`):
     exists in the `to_rule`, it will be overwritten.
   * `copy_no_overwrite <attr> <from_rule>`:  Copies the value of `attr` between
     rules. If it exists in the `to_rule`, no action is taken.
+  * `copy_rule <from_rule>`: Copies the value of `from_rule` to the `to_rule`. If
+    `to_rule` exists, it will be overwritten.
   * `dict_add <attr> <(key:value)(s)>`:  Sets the value of a key for the dict
     attribute `attr`. If the key was already present, it will _not_ be overwritten
   * `dict_set <attr> <(key:value)(s)>`:  Sets the value of a key for the dict
@@ -185,6 +187,9 @@ buildozer 'new cc_binary new_bin before tests' //:__pkg__
 # Copy an attribute from `protolib` to `py_protolib`.
 buildozer 'copy testonly protolib' //pkg:py_protolib
 
+# Copy a rule from `protolib` to `py_protolib`.
+buildozer 'copy_rule protolib' //pkg:py_protolib
+
 # Set two attributes in the same rule
 buildozer 'set compile 1' 'set srcmap 1' //pkg:rule
 

buildozer/buildozer_test.sh

@@ -866,6 +866,46 @@ go_binary(name = "to")'
   assert_err "rule 'from' does not have attribute 'visibility'"
 }
 
+function test_copy_rule() {
+  in='proto_library(name = "from", visibility = ["://foo"] + CONST)
+
+cc_binary(name = "to")'
+
+  run "$in" 'copy_rule from' '//pkg:to'
+  assert_equals 'proto_library(
+    name = "from",
+    visibility = ["://foo"] + CONST,
+)
+
+cc_binary(
+    name = "to",
+    visibility = ["://foo"] + CONST,
+)'
+}
+
+function test_copy_rule_overwrite() {
+  in='proto_library(name = "from", testonly = 1)
+
+cc_binary(name = "to", testonly = 2)'
+
+  run "$in" 'copy_rule from' '//pkg:to'
+  assert_equals 'proto_library(
+    name = "from",
+    testonly = 1,
+)
+
+cc_binary(
+    name = "to",
+    testonly = 1,
+)'
+}
+
+function test_copy_rule_no_from_rule() {
+  in='go_binary(name = "to")'
+  ERROR=2 run "$in" 'copy_rule from' '//pkg:to'
+  assert_err "could not find rule 'from'"
+}
+
 function test_set_kind() {
   in='cc_library(name = "a")'
 

edit/buildozer.go

@@ -563,6 +563,28 @@ func cmdCopyNoOverwrite(opts *Options, env CmdEnvironment) (*build.File, error)
 	return copyAttributeBetweenRules(env, attrName, from)
 }
 
+func cmdCopyRule(opts *Options, env CmdEnvironment) (*build.File, error) {
+	from := env.Args[0]
+
+	fromRule := FindRuleByName(env.File, from)
+	if fromRule == nil {
+		return nil, fmt.Errorf("could not find rule '%s'", from)
+	}
+	for _, key := range env.Rule.AttrKeys() {
+		if key != "name" {
+			env.Rule.DelAttr(key)
+		}
+	}
+	for _, key := range fromRule.AttrKeys() {
+		if key != "name" {
+			copyAttributeBetweenRules(env, key, from)
+		}
+	}
+
+	return env.File, nil
+
+}
+
 // cmdDictAdd adds a key to a dict, if that key does _not_ exit already.
 func cmdDictAdd(opts *Options, env CmdEnvironment) (*build.File, error) {
 	attr := env.Args[0]
@@ -727,6 +749,7 @@ var AllCommands = map[string]CommandInfo{
 	"set_if_absent":     {cmdSetIfAbsent, true, 1, -1, "<attr> <value(s)>"},
 	"copy":              {cmdCopy, true, 2, 2, "<attr> <from_rule>"},
 	"copy_no_overwrite": {cmdCopyNoOverwrite, true, 2, 2, "<attr> <from_rule>"},
+	"copy_rule":         {cmdCopyRule, true, 1, 1, "<from_rule>"},
 	"dict_add":          {cmdDictAdd, true, 2, -1, "<attr> <(key:value)(s)>"},
 	"dict_set":          {cmdDictSet, true, 2, -1, "<attr> <(key:value)(s)>"},
 	"dict_remove":       {cmdDictRemove, true, 2, -1, "<attr> <key(s)>"},