Append path into trimpath if option already exists

.bazelci/presubmit.yml

@@ -187,6 +187,9 @@ tasks:
     - "-//tests/core/go_plugin:go_plugin"
     - "-//tests/core/go_plugin:go_default_test"
     - "-//tests/core/go_plugin:plugin"
+    - "-//tests/core/go_plugin_with_proto_library:go_plugin_with_proto_library"
+    - "-//tests/core/go_plugin_with_proto_library:go_default_test"
+    - "-//tests/core/go_plugin_with_proto_library:plugin"
     - "-//tests/core/go_proto_library:all"
     - "-//tests/core/go_proto_library_importmap:foo_go_proto"
     - "-//tests/core/go_proto_library_importmap:foo_proto"
@@ -299,6 +302,9 @@ tasks:
     - "-//tests/core/go_plugin:go_plugin"
     - "-//tests/core/go_plugin:go_default_test"
     - "-//tests/core/go_plugin:plugin"
+    - "-//tests/core/go_plugin_with_proto_library:go_plugin_with_proto_library"
+    - "-//tests/core/go_plugin_with_proto_library:go_default_test"
+    - "-//tests/core/go_plugin_with_proto_library:plugin"
     - "-//tests/core/go_proto_library:all"
     - "-//tests/core/go_proto_library_importmap:importmap_test"
     - "-//tests/core/go_test:data_test"

go/tools/builders/compilepkg.go

@@ -277,14 +277,14 @@ func compileArchive(
 			return err
 		}
 
-		gcFlags = append(gcFlags, "-trimpath="+srcDir)
+		gcFlags = append(gcFlags, createTrimPath(gcFlags, srcDir))
 	} else {
 		if cgoExportHPath != "" {
 			if err := ioutil.WriteFile(cgoExportHPath, nil, 0666); err != nil {
 				return err
 			}
 		}
-		gcFlags = append(gcFlags, "-trimpath=.")
+		gcFlags = append(gcFlags, createTrimPath(gcFlags, "."))
 	}
 
 	// Check that the filtered sources don't import anything outside of
@@ -511,6 +511,16 @@ func runNogo(ctx context.Context, workDir string, nogoPath string, srcs []string
 	return nil
 }
 
+func createTrimPath(gcFlags []string, path string) string {
+	for _, flag := range gcFlags {
+		if strings.HasPrefix(flag, "-trimpath=") {
+			return flag + ":" + path
+		}
+	}
+
+	return "-trimpath=" + path
+}
+
 func sanitizePathForIdentifier(path string) string {
 	return strings.Map(func(r rune) rune {
 		if 'A' <= r && r <= 'Z' ||

tests/core/go_plugin_with_proto_library/BUILD.bazel

@@ -0,0 +1,31 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_test", "go_library")
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+
+test_suite(name = "go_plugin_with_proto_library")
+
+go_test(
+    name = "go_default_test",
+    srcs = ["all_test.go"],
+    data = [":plugin"],
+    deps = [":validate"],
+)
+
+go_binary(
+    name = "plugin",
+    srcs = ["plugin.go"],
+    out = "plugin.so",
+    deps = [":validate"],
+    linkmode = "plugin",
+)
+
+proto_library(
+    name = "validate_proto",
+    srcs = ["validate.proto"],
+)
+
+go_proto_library(
+    name = "validate",
+    importpath = "go_plugin_with_proto_library/validate",
+    proto = ":validate_proto",
+    gc_goopts = ["-trimpath=$(BINDIR)=>."],
+)

tests/core/go_plugin_with_proto_library/README.rst

@@ -0,0 +1,16 @@
+Go Plugin supporting protobufs
+==============================
+
+.. _go_binary: /go/core.rst#_go_binary
+
+Tests to ensure a protobuf can be included into a plugin and host.
+
+all_test
+--------
+
+1. Test that a go_binary_ rule can write its shared object file with a custom
+   name in the package directory (not the mode directory) when the plugin
+   depends on a protobuf.
+
+2. Test that a plugin with a protobuf dependency built using a go_binary_ rule
+   can be loaded by a Go program and that its symbols are working as expected.

tests/core/go_plugin_with_proto_library/all_test.go

@@ -0,0 +1,36 @@
+package main_test
+
+import (
+	"go_plugin_with_proto_library/validate"
+	"os"
+	"plugin"
+	"testing"
+)
+
+const RuleName = "test"
+
+func TestPluginCreated(t *testing.T) {
+	_, err := os.Stat("plugin.so")
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestPluginWorks(t *testing.T) {
+	p, err := plugin.Open("plugin.so")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	symProto, err := p.Lookup("SomeProto")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	proto := symProto.(*validate.MessageRules)
+	if *proto.Name != RuleName {
+		t.Errorf("expected %#v, got %#v", RuleName, proto.Name)
+	}
+}

tests/core/go_plugin_with_proto_library/plugin.go

@@ -0,0 +1,7 @@
+package main
+
+import "go_plugin_with_proto_library/validate"
+
+var testValue = "test"
+
+var SomeProto = validate.MessageRules{Name: &testValue}

tests/core/go_plugin_with_proto_library/validate.proto

@@ -0,0 +1,6 @@
+syntax = "proto2";
+package validate;
+
+message MessageRules {
+    required string name = 1;
+}