Use own ErrNoData, not from light-client

client/errors.go

@@ -0,0 +1,22 @@
+package client
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+//--------------------------------------------
+
+var errNoData = fmt.Errorf("No data returned for query")
+
+// IsNoDataErr checks whether an error is due to a query returning empty data
+func IsNoDataErr(err error) bool {
+	return errors.Cause(err) == errNoData
+}
+
+func ErrNoData() error {
+	return errors.WithStack(errNoData)
+}
+
+//--------------------------------------------

client/errors_test.go

@@ -0,0 +1,18 @@
+package client
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestErrorNoData(t *testing.T) {
+	e1 := ErrNoData()
+	e1.Error()
+	assert.True(t, IsNoDataErr(e1))
+
+	e2 := errors.New("foobar")
+	assert.False(t, IsNoDataErr(e2))
+	assert.False(t, IsNoDataErr(nil))
+}

client/query.go

@@ -38,7 +38,7 @@ func GetWithProof(key []byte, reqHeight int, node client.Client,
 		return
 	}
 	if len(resp.Key) == 0 || len(resp.Proof) == 0 {
-		err = lc.ErrNoData()
+		err = ErrNoData()
 		return
 	}
 	if resp.Height == 0 {
@@ -84,7 +84,7 @@ func GetWithProof(key []byte, reqHeight int, node client.Client,
 			err = errors.Wrap(err, "Couldn't verify proof")
 			return
 		}
-		err = lc.ErrNoData()
+		err = ErrNoData()
 		proof = aproof
 	}
 

client/query_test.go

@@ -9,14 +9,14 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/tendermint/go-wire"
-	lc "github.com/tendermint/light-client"
 	"github.com/tendermint/light-client/certifiers"
 	certclient "github.com/tendermint/light-client/certifiers/client"
+	"github.com/tendermint/tmlibs/log"
+
 	nm "github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/rpc/client"
 	rpctest "github.com/tendermint/tendermint/rpc/test"
 	"github.com/tendermint/tendermint/types"
-	"github.com/tendermint/tmlibs/log"
 
 	sdkapp "github.com/cosmos/cosmos-sdk/app"
 	"github.com/cosmos/cosmos-sdk/modules/eyes"
@@ -98,7 +98,7 @@ func TestAppProofs(t *testing.T) {
 	// Test non-existing key.
 	missing := []byte("my-missing-key")
 	bs, _, proof, err = GetWithProof(missing, 0, cl, cert)
-	require.True(lc.IsNoDataErr(err))
+	require.True(IsNoDataErr(err))
 	require.Nil(bs)
 	require.NotNil(proof)
 	err = proof.Verify(missing, nil, rootHash)