From f9a9191e1116df5127fa31ddd3655594c0071602 Mon Sep 17 00:00:00 2001
From: Noah Dietz <noahdietz@users.noreply.github.com>
Date: Tue, 8 Nov 2022 14:35:16 -0800
Subject: [PATCH] fix(gengapic): document client/bidi streaming unsupported in
 REST (#1181)

---
 internal/gengapic/gengapic.go      |  3 +++
 internal/gengapic/gengapic_test.go | 13 +++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/internal/gengapic/gengapic.go b/internal/gengapic/gengapic.go
index ea961d62..0c65309e 100644
--- a/internal/gengapic/gengapic.go
+++ b/internal/gengapic/gengapic.go
@@ -479,6 +479,9 @@ func (g *generator) methodDoc(m *descriptor.MethodDescriptorProto) {
 		return
 	}
 
+	if containsTransport(g.opts.transports, rest) && m.GetClientStreaming() {
+		com = fmt.Sprintf("%s\n\nThis method is not supported for the REST transport.", com)
+	}
 	// If the method is marked as deprecated and there is no comment, then add default deprecation comment.
 	// If the method has a comment but it does not include a deprecation notice, then append a default deprecation notice.
 	// If the method includes a deprecation notice at the beginning of the comment, prepend a comment stating the method is deprecated and use the included deprecation notice.
diff --git a/internal/gengapic/gengapic_test.go b/internal/gengapic/gengapic_test.go
index 2015960a..fc422f10 100644
--- a/internal/gengapic/gengapic_test.go
+++ b/internal/gengapic/gengapic_test.go
@@ -564,8 +564,9 @@ func TestMethodDoc(t *testing.T) {
 	}
 
 	for _, tst := range []struct {
-		in, want   string
-		deprecated bool
+		in, want                    string
+		clientStreaming, deprecated bool
+		opts                        options
 	}{
 		{
 			in:   "",
@@ -595,11 +596,19 @@ func TestMethodDoc(t *testing.T) {
 			want:       "// MyMethod is deprecated.\n//\n// Deprecated: MyMethod may be removed in a future version.\n",
 			deprecated: true,
 		},
+		{
+			in:              "Does client streaming stuff.\n It also does other stuffs.",
+			want:            "// MyMethod does client streaming stuff.\n// It also does other stuffs.\n//\n// This method is not supported for the REST transport.\n",
+			clientStreaming: true,
+			opts:            options{transports: []transport{rest}},
+		},
 	} {
+		g.opts = &tst.opts
 		g.comments[m] = tst.in
 		m.Options = &descriptor.MethodOptions{
 			Deprecated: proto.Bool(tst.deprecated),
 		}
+		m.ClientStreaming = proto.Bool(tst.clientStreaming)
 		g.pt.Reset()
 		g.methodDoc(m)
 		if diff := cmp.Diff(g.pt.String(), tst.want); diff != "" {