Hard code dependency resolution bindings for @go_googleapis and WKTs

* proto.csv is a table that lists Well Known .proto files and all
  .proto files in @go_googleapis. For each proto import string, it
  lists the proto_library label, the Go import path, and the
  go_proto_library label. This was generated using an ad hoc Python
  script (not included).
* Maps are generated from this file and incorporated into the
  dependency resolution logic in the proto and go extensions.

When #12 is implemented, we can index rules in external repositories,
and we won't need this. We need it for now because there's no clear
correspondence between proto and Go import strings and the libraries
that should be included.

Related bazel-contrib/rules_go#1548

internal/config/constants.go

@@ -39,18 +39,6 @@ const (
 	// "compilers" attribute of go_proto_library rules.
 	GrpcCompilerLabel = "@io_bazel_rules_go//proto:go_grpc"
 
-	// WellKnownTypesProtoRepo is the repository containing proto_library rules
-	// for the Well Known Types.
-	WellKnownTypesProtoRepo = "com_google_protobuf"
-	// WellKnownTypeProtoPrefix is the proto import path prefix for the
-	// Well Known Types.
-	WellKnownTypesProtoPrefix = "google/protobuf"
-	// WellKnownTypesGoPrefix is the import path for the Go repository containing
-	// pre-generated code for the Well Known Types.
-	WellKnownTypesGoPrefix = "github.com/golang/protobuf"
-	// WellKnownTypesPkg is the package name for the predefined WKTs in rules_go.
-	WellKnownTypesPkg = "proto/wkt"
-
 	// GazelleImportsKey is an internal attribute that lists imported packages
 	// on generated rules. It is replaced with "deps" during import resolution.
 	GazelleImportsKey = "_gazelle_imports"

internal/language/go/BUILD.bazel

@@ -15,6 +15,22 @@ genrule(
     tools = ["//internal/language/go/gen_std_package_list"],
 )
 
+genrule(
+    name = "known_proto_imports",
+    srcs = ["//internal/language/proto:proto.csv"],
+    outs = ["known_proto_imports.go"],
+    cmd = "$(location //internal/language/proto/gen:gen_known_imports) -proto_csv $< -known_imports $@ -package golang -var knownProtoImports -key 0 -value 3",
+    tools = ["//internal/language/proto/gen:gen_known_imports"],
+)
+
+genrule(
+    name = "known_go_imports",
+    srcs = ["//internal/language/proto:proto.csv"],
+    outs = ["known_go_imports.go"],
+    cmd = "$(location //internal/language/proto/gen:gen_known_imports) -proto_csv $< -known_imports $@ -package golang -var knownGoProtoImports -key 2 -value 3",
+    tools = ["//internal/language/proto/gen:gen_known_imports"],
+)
+
 go_library(
     name = "go_default_library",
     srcs = [
@@ -24,6 +40,8 @@ go_library(
         "fix.go",
         "generate.go",
         "kinds.go",
+        "known_go_imports.go",
+        "known_proto_imports.go",
         "lang.go",
         "package.go",
         "resolve.go",

internal/language/go/resolve.go

@@ -113,7 +113,7 @@ func resolveGo(gc *goConfig, ix *resolve.RuleIndex, rc *repos.RemoteCache, r *ru
 		return label.NoLabel, skipImportError
 	}
 
-	if l := resolveWellKnownGo(imp); !l.Equal(label.NoLabel) {
+	if l, ok := knownGoProtoImports[imp]; ok {
 		return l, nil
 	}
 
@@ -140,42 +140,6 @@ func isStandard(imp string) bool {
 	return stdPackages[imp]
 }
 
-func resolveWellKnownGo(imp string) label.Label {
-	// keep in sync with @io_bazel_rules_go//proto/wkt:well_known_types.bzl
-	// TODO(jayconrod): in well_known_types.bzl, write the import paths and
-	// targets in a public dict. Import it here, and use it to generate this code.
-	switch imp {
-	case "github.com/golang/protobuf/ptypes/any",
-		"github.com/golang/protobuf/ptypes/api",
-		"github.com/golang/protobuf/protoc-gen-go/descriptor",
-		"github.com/golang/protobuf/ptypes/duration",
-		"github.com/golang/protobuf/ptypes/empty",
-		"google.golang.org/genproto/protobuf/field_mask",
-		"google.golang.org/genproto/protobuf/source_context",
-		"github.com/golang/protobuf/ptypes/struct",
-		"github.com/golang/protobuf/ptypes/timestamp",
-		"github.com/golang/protobuf/ptypes/wrappers":
-		return label.Label{
-			Repo: config.RulesGoRepoName,
-			Pkg:  config.WellKnownTypesPkg,
-			Name: path.Base(imp) + "_go_proto",
-		}
-	case "github.com/golang/protobuf/protoc-gen-go/plugin":
-		return label.Label{
-			Repo: config.RulesGoRepoName,
-			Pkg:  config.WellKnownTypesPkg,
-			Name: "compiler_plugin_go_proto",
-		}
-	case "google.golang.org/genproto/protobuf/ptype":
-		return label.Label{
-			Repo: config.RulesGoRepoName,
-			Pkg:  config.WellKnownTypesPkg,
-			Name: "type_go_proto",
-		}
-	}
-	return label.NoLabel
-}
-
 func resolveWithIndexGo(ix *resolve.RuleIndex, imp string, from label.Label) (label.Label, error) {
 	matches := ix.FindRulesByImport(resolve.ImportSpec{Lang: "go", Imp: imp}, "go")
 	var bestMatch resolve.FindResult
@@ -248,13 +212,16 @@ func resolveVendored(rc *repos.RemoteCache, imp string) (label.Label, error) {
 }
 
 func resolveProto(gc *goConfig, ix *resolve.RuleIndex, rc *repos.RemoteCache, r *rule.Rule, imp string, from label.Label) (label.Label, error) {
-	if !strings.HasSuffix(imp, ".proto") {
-		return label.NoLabel, fmt.Errorf("can't import non-proto: %q", imp)
+	if wellKnownProtos[imp] {
+		return label.NoLabel, skipImportError
 	}
-	stem := imp[:len(imp)-len(".proto")]
 
-	if isWellKnownProto(stem) {
-		return label.NoLabel, skipImportError
+	if l, ok := knownProtoImports[imp]; ok {
+		if l.Equal(from) {
+			return label.NoLabel, skipImportError
+		} else {
+			return l, nil
+		}
 	}
 
 	if l, err := resolveWithIndexProto(ix, imp, from); err == nil || err == skipImportError {
@@ -282,22 +249,18 @@ func resolveProto(gc *goConfig, ix *resolve.RuleIndex, rc *repos.RemoteCache, r
 // TODO(jayconrod): generate from
 // @io_bazel_rules_go//proto/wkt:WELL_KNOWN_TYPE_PACKAGES
 var wellKnownProtos = map[string]bool{
-	"google/protobuf/any":             true,
-	"google/protobuf/api":             true,
-	"google/protobuf/compiler_plugin": true,
-	"google/protobuf/descriptor":      true,
-	"google/protobuf/duration":        true,
-	"google/protobuf/empty":           true,
-	"google/protobuf/field_mask":      true,
-	"google/protobuf/source_context":  true,
-	"google/protobuf/struct":          true,
-	"google/protobuf/timestamp":       true,
-	"google/protobuf/type":            true,
-	"google/protobuf/wrappers":        true,
-}
-
-func isWellKnownProto(stem string) bool {
-	return wellKnownProtos[stem]
+	"google/protobuf/any.proto":             true,
+	"google/protobuf/api.proto":             true,
+	"google/protobuf/compiler_plugin.proto": true,
+	"google/protobuf/descriptor.proto":      true,
+	"google/protobuf/duration.proto":        true,
+	"google/protobuf/empty.proto":           true,
+	"google/protobuf/field_mask.proto":      true,
+	"google/protobuf/source_context.proto":  true,
+	"google/protobuf/struct.proto":          true,
+	"google/protobuf/timestamp.proto":       true,
+	"google/protobuf/type.proto":            true,
+	"google/protobuf/wrappers.proto":        true,
 }
 
 func resolveWithIndexProto(ix *resolve.RuleIndex, imp string, from label.Label) (label.Label, error) {
@@ -308,10 +271,10 @@ func resolveWithIndexProto(ix *resolve.RuleIndex, imp string, from label.Label)
 	if len(matches) > 1 {
 		return label.NoLabel, fmt.Errorf("multiple rules (%s and %s) may be imported with %q from %s", matches[0].Label, matches[1].Label, imp, from)
 	}
-	// If some go_library embeds the go_proto_library we found, use that instead.
-	importpath := matches[0].Rule.AttrString("importpath")
-	if l, err := resolveWithIndexGo(ix, importpath, from); err == nil {
-		return l, nil
+	// TODO(#247): this check is not sufficient. We should check whether the
+	// match embeds this library (possibly transitively).
+	if from.Equal(matches[0].Label) {
+		return label.NoLabel, skipImportError
 	}
 	return matches[0].Label, nil
 }

internal/language/go/resolve_test.go

@@ -568,14 +568,17 @@ go_proto_library(
         "google/protobuf/timestamp.proto",
         "google/protobuf/type.proto",
         "google/protobuf/wrappers.proto",
+        "google/api/http.proto",
+        "google/rpc/status.proto",
+        "google/type/latlng.proto",
    ],
 )
 
 go_library(
     name = "wkts_go_lib",
     _imports = [
         "github.com/golang/protobuf/ptypes/any",
-        "github.com/golang/protobuf/ptypes/api",
+        "google.golang.org/genproto/protobuf/api",
         "github.com/golang/protobuf/protoc-gen-go/descriptor",
         "github.com/golang/protobuf/ptypes/duration",
         "github.com/golang/protobuf/ptypes/empty",
@@ -586,15 +589,28 @@ go_library(
         "github.com/golang/protobuf/ptypes/wrappers",
         "github.com/golang/protobuf/protoc-gen-go/plugin",
         "google.golang.org/genproto/protobuf/ptype",
+        "google.golang.org/genproto/googleapis/api/annotations",
+        "google.golang.org/genproto/googleapis/rpc/status",
+        "google.golang.org/genproto/googleapis/type/latlng",
    ],
 )
 `},
 			want: `
-go_proto_library(name = "wkts_go_proto")
+go_proto_library(
+    name = "wkts_go_proto",
+    deps = [
+        "@go_googleapis//google/api:annotations_go_proto",
+        "@go_googleapis//google/rpc:status_go_proto",
+        "@go_googleapis//google/type:latlng_go_proto",
+    ],
+)
 
 go_library(
     name = "wkts_go_lib",
     deps = [
+        "@go_googleapis//google/api:annotations_go_proto",
+        "@go_googleapis//google/rpc:status_go_proto",
+        "@go_googleapis//google/type:latlng_go_proto",
         "@io_bazel_rules_go//proto/wkt:any_go_proto",
         "@io_bazel_rules_go//proto/wkt:api_go_proto",
         "@io_bazel_rules_go//proto/wkt:compiler_plugin_go_proto",
@@ -609,6 +625,39 @@ go_library(
         "@io_bazel_rules_go//proto/wkt:wrappers_go_proto",
     ],
 )
+`,
+		}, {
+			desc: "proto_self_import",
+			old: buildFile{content: `
+proto_library(
+    name = "foo_proto",
+    srcs = [
+        "a.proto",
+        "b.proto",
+    ],
+)
+
+go_proto_library(
+    name = "foo_go_proto",
+    importpath = "foo",
+    proto = ":foo_proto",
+    _imports = ["a.proto"],
+)
+`},
+			want: `
+proto_library(
+    name = "foo_proto",
+    srcs = [
+        "a.proto",
+        "b.proto",
+    ],
+)
+
+go_proto_library(
+    name = "foo_go_proto",
+    importpath = "foo",
+    proto = ":foo_proto",
+)
 `,
 		},
 	} {

internal/language/proto/BUILD.bazel

@@ -2,6 +2,14 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 # gazelle:exclude testdata
 
+genrule(
+    name = "known_imports",
+    srcs = ["proto.csv"],
+    outs = ["known_imports.go"],
+    cmd = "$(location //internal/language/proto/gen:gen_known_imports) -proto_csv $< -known_imports $@ -package proto -var knownImports -key 0 -value 1",
+    tools = ["//internal/language/proto/gen:gen_known_imports"],
+)
+
 go_library(
     name = "go_default_library",
     srcs = [
@@ -11,6 +19,7 @@ go_library(
         "fix.go",
         "generate.go",
         "kinds.go",
+        "known_imports.go",
         "lang.go",
         "package.go",
         "resolve.go",
@@ -21,7 +30,6 @@ go_library(
         "//internal/config:go_default_library",
         "//internal/label:go_default_library",
         "//internal/language:go_default_library",
-        "//internal/pathtools:go_default_library",
         "//internal/repos:go_default_library",
         "//internal/resolve:go_default_library",
         "//internal/rule:go_default_library",
@@ -48,3 +56,5 @@ go_test(
         "//vendor/github.com/bazelbuild/buildtools/build:go_default_library",
     ],
 )
+
+exports_files(["proto.csv"])

internal/language/proto/gen/BUILD.bazel

@@ -0,0 +1,15 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["gen_known_imports.go"],
+    importpath = "github.com/bazelbuild/bazel-gazelle/internal/language/proto/gen",
+    visibility = ["//visibility:private"],
+    deps = ["//internal/label:go_default_library"],
+)
+
+go_binary(
+    name = "gen_known_imports",
+    embed = [":go_default_library"],
+    visibility = ["//:__subpackages__"],
+)