ssh: Add tests for SSHReceivePack exercising error conditions

We're currently missing tests for SSHReceivePack which exercise error
conditions that may happen when the underlying communitcation between
git-send-pack(1) and git-receive-pack(1) fails. Add some tests to verify
our current behaviour.

Note that this also exposes an error where we're not reporting errors to
the gRPC client at all even though the upload has failed.

1 files changed, 81 insertions, 0 deletions

diff --git a/internal/gitaly/service/ssh/receive_pack_test.go b/internal/gitaly/service/ssh/receive_pack_test.go
index fe04dada4..625d1abd3 100644
--- a/internal/gitaly/service/ssh/receive_pack_test.go
+++ b/internal/gitaly/service/ssh/receive_pack_test.go
@@ -201,6 +201,87 @@ func TestReceivePack_success(t *testing.T) {
 	}, payload)
 }
 
+func TestReceivePack_client(t *testing.T) {
+	t.Parallel()
+
+	ctx := testhelper.Context(t)
+	cfg := testcfg.Build(t)
+	cfg.SocketPath = runSSHServer(t, cfg)
+
+	for _, tc := range []struct {
+		desc              string
+		writeRequest      func(*testing.T, io.Writer)
+		expectedErrorCode int32
+		expectedStderr    string
+	}{
+		{
+			desc: "no commands",
+			writeRequest: func(t *testing.T, stdin io.Writer) {
+				gittest.WritePktlineFlush(t, stdin)
+			},
+		},
+		{
+			desc: "garbage",
+			writeRequest: func(t *testing.T, stdin io.Writer) {
+				gittest.WritePktlineString(t, stdin, "garbage")
+			},
+			expectedErrorCode: 128,
+			expectedStderr:    "fatal: protocol error: expected old/new/ref, got 'garbage'\n",
+		},
+		{
+			desc: "command without flush",
+			writeRequest: func(t *testing.T, stdin io.Writer) {
+				gittest.WritePktlinef(t, stdin, "%[1]s %[1]s refs/heads/main", gittest.DefaultObjectHash.ZeroOID)
+			},
+			expectedErrorCode: 128,
+			expectedStderr:    "fatal: the remote end hung up unexpectedly\n",
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			repoProto, _ := gittest.CreateRepository(ctx, t, cfg)
+
+			stream, err := newSSHClient(t, cfg.SocketPath).SSHReceivePack(ctx)
+			require.NoError(t, err)
+
+			var observedErrorCode int32
+			var stderr bytes.Buffer
+			errCh := make(chan error, 1)
+			go func() {
+				stdout := streamio.NewReader(func() ([]byte, error) {
+					msg, err := stream.Recv()
+					if errorCode := msg.GetExitStatus().GetValue(); errorCode != 0 {
+						require.Zero(t, observedErrorCode, "must not receive multiple messages with non-zero exit code")
+						observedErrorCode = errorCode
+					}
+
+					// Write stderr so we can verify what git-receive-pack(1)
+					// complains about.
+					_, writeErr := stderr.Write(msg.GetStderr())
+					require.NoError(t, writeErr)
+
+					return msg.GetStdout(), err
+				})
+
+				_, err := io.Copy(io.Discard, stdout)
+				errCh <- err
+			}()
+
+			require.NoError(t, stream.Send(&gitalypb.SSHReceivePackRequest{Repository: repoProto, GlId: "user-123"}))
+
+			stdin := streamio.NewWriter(func(b []byte) error {
+				return stream.Send(&gitalypb.SSHReceivePackRequest{Stdin: b})
+			})
+			tc.writeRequest(t, stdin)
+			require.NoError(t, stream.CloseSend())
+
+			// Even if the request has failed we still don't see any errors at all.
+			require.NoError(t, <-errCh)
+			require.Equal(t, tc.expectedErrorCode, observedErrorCode)
+			require.Equal(t, tc.expectedStderr, stderr.String())
+		})
+	}
+}
+
 func TestReceive_gitProtocol(t *testing.T) {
 	t.Parallel()