wal: fix shadowed variables

Fixes for https://github.com/coreos/etcd/issues/3954.

wal/encoder.go

@@ -68,7 +68,7 @@ func (e *encoder) encode(rec *walpb.Record) error {
 		}
 		data = e.buf[:n]
 	}
-	if err := writeInt64(e.bw, int64(len(data)), e.uint64buf); err != nil {
+	if err = writeInt64(e.bw, int64(len(data)), e.uint64buf); err != nil {
 		return err
 	}
 	_, err = e.bw.Write(data)

wal/wal.go

@@ -102,8 +102,7 @@ func Create(dirpath string, metadata []byte) (*WAL, error) {
 	if err != nil {
 		return nil, err
 	}
-	err = l.Lock()
-	if err != nil {
+	if err = l.Lock(); err != nil {
 		return nil, err
 	}
 
@@ -121,7 +120,7 @@ func Create(dirpath string, metadata []byte) (*WAL, error) {
 	if err := w.encoder.encode(&walpb.Record{Type: metadataType, Data: metadata}); err != nil {
 		return nil, err
 	}
-	if err = w.SaveSnapshot(walpb.Snapshot{}); err != nil {
+	if err := w.SaveSnapshot(walpb.Snapshot{}); err != nil {
 		return nil, err
 	}
 	return w, nil
@@ -339,25 +338,25 @@ func (w *WAL) cut() error {
 	w.f = ft
 	prevCrc := w.encoder.crc.Sum32()
 	w.encoder = newEncoder(w.f, prevCrc)
-	if err := w.saveCrc(prevCrc); err != nil {
+	if err = w.saveCrc(prevCrc); err != nil {
 		return err
 	}
-	if err := w.encoder.encode(&walpb.Record{Type: metadataType, Data: w.metadata}); err != nil {
+	if err = w.encoder.encode(&walpb.Record{Type: metadataType, Data: w.metadata}); err != nil {
 		return err
 	}
-	if err := w.saveState(&w.state); err != nil {
+	if err = w.saveState(&w.state); err != nil {
 		return err
 	}
 	// close temp wal file
-	if err := w.sync(); err != nil {
+	if err = w.sync(); err != nil {
 		return err
 	}
-	if err := w.f.Close(); err != nil {
+	if err = w.f.Close(); err != nil {
 		return err
 	}
 
 	// atomically move temp wal file to wal file
-	if err := os.Rename(ftpath, fpath); err != nil {
+	if err = os.Rename(ftpath, fpath); err != nil {
 		return err
 	}
 
@@ -366,8 +365,7 @@ func (w *WAL) cut() error {
 	if err != nil {
 		return err
 	}
-	err = fileutil.Preallocate(f, segmentSizeBytes)
-	if err != nil {
+	if err = fileutil.Preallocate(f, segmentSizeBytes); err != nil {
 		plog.Errorf("failed to allocate space when creating new wal file (%v)", err)
 		return err
 	}
@@ -382,8 +380,7 @@ func (w *WAL) cut() error {
 		return err
 	}
 
-	err = l.Lock()
-	if err != nil {
+	if err := l.Lock(); err != nil {
 		return err
 	}
 	w.locks = append(w.locks, l)

wal/wal_test.go

@@ -153,10 +153,10 @@ func TestCut(t *testing.T) {
 
 	state := raftpb.HardState{Term: 1}
 	// TODO(unihorn): remove this when cut can operate on an empty file
-	if err := w.Save(state, []raftpb.Entry{{}}); err != nil {
+	if err = w.Save(state, []raftpb.Entry{{}}); err != nil {
 		t.Fatal(err)
 	}
-	if err := w.cut(); err != nil {
+	if err = w.cut(); err != nil {
 		t.Fatal(err)
 	}
 	wname := walName(1, 1)
@@ -165,10 +165,10 @@ func TestCut(t *testing.T) {
 	}
 
 	es := []raftpb.Entry{{Index: 1, Term: 1, Data: []byte{1}}}
-	if err := w.Save(raftpb.HardState{}, es); err != nil {
+	if err = w.Save(raftpb.HardState{}, es); err != nil {
 		t.Fatal(err)
 	}
-	if err := w.cut(); err != nil {
+	if err = w.cut(); err != nil {
 		t.Fatal(err)
 	}
 	snap := walpb.Snapshot{Index: 2, Term: 1}
@@ -212,7 +212,7 @@ func TestRecover(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := w.SaveSnapshot(walpb.Snapshot{}); err != nil {
+	if err = w.SaveSnapshot(walpb.Snapshot{}); err != nil {
 		t.Fatal(err)
 	}
 	ents := []raftpb.Entry{{Index: 1, Term: 1, Data: []byte{1}}, {Index: 2, Term: 2, Data: []byte{2}}}
@@ -385,10 +385,10 @@ func TestOpenAtUncommittedIndex(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := w.SaveSnapshot(walpb.Snapshot{}); err != nil {
+	if err = w.SaveSnapshot(walpb.Snapshot{}); err != nil {
 		t.Fatal(err)
 	}
-	if err := w.Save(raftpb.HardState{}, []raftpb.Entry{{Index: 0}}); err != nil {
+	if err = w.Save(raftpb.HardState{}, []raftpb.Entry{{Index: 0}}); err != nil {
 		t.Fatal(err)
 	}
 	w.Close()
@@ -398,7 +398,7 @@ func TestOpenAtUncommittedIndex(t *testing.T) {
 		t.Fatal(err)
 	}
 	// commit up to index 0, try to read index 1
-	if _, _, _, err := w.ReadAll(); err != nil {
+	if _, _, _, err = w.ReadAll(); err != nil {
 		t.Errorf("err = %v, want nil", err)
 	}
 	w.Close()