Allow MatchAttrs to be slices (roll forward) (bazel-contrib#744)

When bazel-contrib#730 was opened, it was based on top of bazel-contrib#720. So the tests were passing on bazel-contrib#730. However, bazel-contrib#720 was reverted on master before bazel-contrib#730 was merged. When merging bazel-contrib#730 onto master, its tests started to fail. This PR reverted bazel-contrib#743 and fixed the failing tests

Fixed bazel-contrib#742

cmd/gazelle/integration_test.go

@@ -2975,3 +2975,65 @@ go_repository(
 		},
 	})
 }
+
+func TestMatchProtoLibrary(t *testing.T) {
+	files := []testtools.FileSpec{
+		{
+			Path: "WORKSPACE",
+		},
+		{
+			Path: "proto/BUILD.bazel",
+			Content: `
+load("@rules_proto//proto:defs.bzl", "proto_library")
+# gazelle:prefix example.com/foo
+
+proto_library(
+	name = "existing_proto",
+	srcs = ["foo.proto"],
+)
+`,
+		},
+		{
+			Path:    "proto/foo.proto",
+			Content: `syntax = "proto3";`,
+		},
+	}
+	dir, cleanup := testtools.CreateFiles(t, files)
+	defer cleanup()
+
+	args := []string{"update"}
+	if err := runGazelle(dir, args); err != nil {
+		t.Fatal(err)
+	}
+
+	testtools.CheckFiles(t, dir, []testtools.FileSpec{
+		{
+			Path: "proto/BUILD.bazel",
+			Content: `
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+# gazelle:prefix example.com/foo
+
+proto_library(
+    name = "existing_proto",
+    srcs = ["foo.proto"],
+    visibility = ["//visibility:public"],
+)
+
+go_proto_library(
+    name = "foo_go_proto",
+    importpath = "example.com/foo",
+    proto = ":existing_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "go_default_library",
+    embed = [":foo_go_proto"],
+    importpath = "example.com/foo",
+    visibility = ["//visibility:public"],
+)`,
+		},
+	})
+}

language/proto/kinds.go

@@ -19,6 +19,7 @@ import "github.com/bazelbuild/bazel-gazelle/rule"
 
 var protoKinds = map[string]rule.KindInfo{
 	"proto_library": {
+		MatchAttrs:    []string{"srcs"},
 		NonEmptyAttrs: map[string]bool{"srcs": true},
 		MergeableAttrs: map[string]bool{
 			"srcs": true,

merger/merger.go

@@ -38,6 +38,7 @@ package merger
 
 import (
 	"fmt"
+	"sort"
 	"strings"
 
 	"github.com/bazelbuild/bazel-gazelle/rule"
@@ -222,19 +223,15 @@ func Match(rules []*rule.Rule, x *rule.Rule, info rule.KindInfo) (*rule.Rule, er
 
 	for _, key := range info.MatchAttrs {
 		var attrMatches []*rule.Rule
-		xvalue := x.AttrString(key)
-		if xvalue == "" {
-			continue
-		}
 		for _, y := range kindMatches {
-			if xvalue == y.AttrString(key) {
+			if attrMatch(x, y, key) {
 				attrMatches = append(attrMatches, y)
 			}
 		}
 		if len(attrMatches) == 1 {
 			return attrMatches[0], nil
 		} else if len(attrMatches) > 1 {
-			return nil, fmt.Errorf("could not merge %s(%s): multiple rules have the same attribute %s = %q", xkind, xname, key, xvalue)
+			return nil, fmt.Errorf("could not merge %s(%s): multiple rules have the same attribute %s", xkind, xname, key)
 		}
 	}
 
@@ -248,3 +245,23 @@ func Match(rules []*rule.Rule, x *rule.Rule, info rule.KindInfo) (*rule.Rule, er
 
 	return nil, nil
 }
+
+func attrMatch(x, y *rule.Rule, key string) bool {
+	xValue := x.AttrString(key)
+	if xValue != "" && xValue == y.AttrString(key) {
+		return true
+	}
+	xValues := x.AttrStrings(key)
+	yValues := y.AttrStrings(key)
+	if xValues == nil || yValues == nil || len(xValues) != len(yValues) {
+		return false
+	}
+	sort.Strings(xValues)
+	sort.Strings(yValues)
+	for i, v := range xValues {
+		if v != yValues[i] {
+			return false
+		}
+	}
+	return true
+}

merger/merger_test.go

@@ -969,6 +969,15 @@ go_binary(name = "y")
 go_binary(name = "z")
 `,
 			wantError: true,
+		}, {
+			desc:      "srcs match",
+			gen:       `proto_library(name = "proto1", srcs = ["foo.proto", "bar.proto"])`,
+			old:       `proto_library(name = "proto2", srcs = ["bar.proto", "foo.proto"])`,
+			wantIndex: 0,
+		}, {
+			desc: "importpath match",
+			gen:  `go_proto_library(name = "go_proto1", importpath="example.com/foo")`,
+			old:  `go_proto_library(name = "go_proto2", importpath="example.com/foo")`,
 		},
 	} {
 		t.Run(tc.desc, func(t *testing.T) {