pass correct working directory to RunPlugin (#17763)

RunPlugin expects the working directory of the program to be passed in
in the plugin request. This was the case until
#15191. In that PR we switched from
passing pwd (which is the same as `ctx.Pwd` a layer above) to
minfo.GetProgramDirectory(), which is the path from which the plugin is
executed. Fix this by passing in `info.WorkingDirectory`, which a layer
above is `ctx.Pwd`.

Add a test for this as well to make sure we're not regressing this
again.

Likely nobody noticed this, because most plugins probably don't rely on
this path, and most providers are not being run using `RunPlugin`.

changelog/pending/20241113--engine--pass-correct-working-directory-to-runplugin.yaml

@@ -0,0 +1,4 @@
+changes:
+- type: fix
+  scope: engine
+  description: Pass correct working directory to RunPlugin

sdk/go/common/resource/plugin/langruntime_plugin.go

@@ -444,7 +444,7 @@ func (h *langhost) RunPlugin(info RunPluginInfo) (io.Reader, io.Reader, context.
 	ctx, kill := context.WithCancel(h.ctx.Request())
 
 	resp, err := h.client.RunPlugin(ctx, &pulumirpc.RunPluginRequest{
-		Pwd:  minfo.GetProgramDirectory(),
+		Pwd:  info.WorkingDirectory,
 		Args: info.Args,
 		Env:  info.Env,
 		Info: minfo,

sdk/go/common/resource/plugin/langruntime_test.go

@@ -15,9 +15,16 @@
 package plugin
 
 import (
+	"context"
+	"errors"
 	"testing"
 
+	pulumirpc "github.com/pulumi/pulumi/sdk/v3/proto/go"
 	"github.com/stretchr/testify/require"
+
+	"google.golang.org/protobuf/types/known/emptypb"
+
+	grpc "google.golang.org/grpc"
 )
 
 func TestMakeExecutablePromptChoices(t *testing.T) {
@@ -42,3 +49,109 @@ func TestMakeExecutablePromptChoices(t *testing.T) {
 	require.Equal(t, choices[3].StringValue, "aaa_does_not_exist")
 	require.Equal(t, choices[3].DisplayName, "aaa_does_not_exist [not found]")
 }
+
+type MockLanguageRuntimeClient struct {
+	RunPluginF (func(ctx context.Context, info *pulumirpc.RunPluginRequest,
+	) (pulumirpc.LanguageRuntime_RunPluginClient, error))
+}
+
+func (m *MockLanguageRuntimeClient) RunPlugin(
+	ctx context.Context, info *pulumirpc.RunPluginRequest, _ ...grpc.CallOption,
+) (pulumirpc.LanguageRuntime_RunPluginClient, error) {
+	return m.RunPluginF(ctx, info)
+}
+
+func (m *MockLanguageRuntimeClient) GetRequiredPlugins(
+	ctx context.Context, in *pulumirpc.GetRequiredPluginsRequest, opts ...grpc.CallOption,
+) (*pulumirpc.GetRequiredPluginsResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) Run(
+	ctx context.Context, in *pulumirpc.RunRequest, opts ...grpc.CallOption,
+) (*pulumirpc.RunResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) GetPluginInfo(
+	ctx context.Context, in *emptypb.Empty, opts ...grpc.CallOption,
+) (*pulumirpc.PluginInfo, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) InstallDependencies(
+	ctx context.Context, in *pulumirpc.InstallDependenciesRequest, opts ...grpc.CallOption,
+) (pulumirpc.LanguageRuntime_InstallDependenciesClient, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) RuntimeOptionsPrompts(
+	ctx context.Context, in *pulumirpc.RuntimeOptionsRequest, opts ...grpc.CallOption,
+) (*pulumirpc.RuntimeOptionsResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) About(
+	ctx context.Context, in *pulumirpc.AboutRequest, opts ...grpc.CallOption,
+) (*pulumirpc.AboutResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) GetProgramDependencies(
+	ctx context.Context, in *pulumirpc.GetProgramDependenciesRequest, opts ...grpc.CallOption,
+) (*pulumirpc.GetProgramDependenciesResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) GenerateProgram(
+	ctx context.Context, in *pulumirpc.GenerateProgramRequest, opts ...grpc.CallOption,
+) (*pulumirpc.GenerateProgramResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) GenerateProject(
+	ctx context.Context, in *pulumirpc.GenerateProjectRequest, opts ...grpc.CallOption,
+) (*pulumirpc.GenerateProjectResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) GeneratePackage(
+	ctx context.Context, in *pulumirpc.GeneratePackageRequest, opts ...grpc.CallOption,
+) (*pulumirpc.GeneratePackageResponse, error) {
+	panic("not implemented")
+}
+
+func (m *MockLanguageRuntimeClient) Pack(
+	ctx context.Context, in *pulumirpc.PackRequest, opts ...grpc.CallOption,
+) (*pulumirpc.PackResponse, error) {
+	panic("not implemented")
+}
+
+func TestRunPluginPassesCorrectPwd(t *testing.T) {
+	t.Parallel()
+
+	returnErr := errors.New("erroring so we don't need to implement the whole thing")
+	mockLanguageRuntime := &MockLanguageRuntimeClient{
+		RunPluginF: func(
+			ctx context.Context, info *pulumirpc.RunPluginRequest,
+		) (pulumirpc.LanguageRuntime_RunPluginClient, error) {
+			require.Equal(t, "/tmp", info.Pwd)
+			return nil, returnErr
+		},
+	}
+
+	pCtx, err := NewContext(nil, nil, nil, nil, "", nil, false, nil)
+	require.NoError(t, err)
+	host := &langhost{
+		ctx:     pCtx,
+		runtime: "go",
+		plug:    nil,
+		client:  mockLanguageRuntime,
+	}
+
+	// Test that the plugin is run with the correct working directory.
+	_, _, _, err = host.RunPlugin(RunPluginInfo{
+		WorkingDirectory: "/tmp",
+	})
+	require.Equal(t, returnErr, err)
+}