Fix linter issues: nakedret

Makefile

@@ -119,6 +119,7 @@ gometalinter: require-gometalinter
 	    --enable=gotypex \
 	    --enable=interfacer \
 	    --enable=misspell \
+	    --enable=nakedret \
 	    --enable=unparam \
 	    --exclude "^internal/.*\.pb\.go" \
 	    --exclude "^pql/pql.peg.go" \

boltdb/attrstore.go

@@ -120,17 +120,20 @@ func (s *attrStore) Close() error {
 }
 
 // Attrs returns a set of attributes by ID.
-func (s *attrStore) Attrs(id uint64) (m map[string]interface{}, err error) {
+func (s *attrStore) Attrs(id uint64) (map[string]interface{}, error) {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 
+	var m map[string]interface{}
+
 	// Check cache for map.
 	if m = s.attrCache.Get(id); m != nil {
 		return m, nil
 	}
 
 	// Find attributes from storage.
-	if err = s.db.View(func(tx *bolt.Tx) error {
+	if err := s.db.View(func(tx *bolt.Tx) error {
+		var err error
 		m, err = txAttrs(tx, id)
 		if err != nil {
 			return err
@@ -143,7 +146,7 @@ func (s *attrStore) Attrs(id uint64) (m map[string]interface{}, err error) {
 	// Add to cache.
 	s.attrCache.Set(id, m)
 
-	return
+	return m, nil
 }
 
 // SetAttrs sets attribute values for a given ID.

enterprise/b/btree.go

@@ -193,7 +193,8 @@ func (q *x) insert(i int, k uint64, ch interface{}) *x {
 	return q
 }
 
-func (q *x) siblings(i int) (l, r *d) {
+func (q *x) siblings(i int) (*d, *d) {
+	var l, r *d
 	if i >= 0 {
 		if i > 0 {
 			l = q.x[i-1].ch.(*d)
@@ -202,7 +203,7 @@ func (q *x) siblings(i int) (l, r *d) {
 			r = q.x[i+1].ch.(*d)
 		}
 	}
-	return
+	return l, r
 }
 
 // -------------------------------------------------------------------------- d
@@ -419,12 +420,14 @@ func (t *tree) find(q interface{}, k uint64) (i int, ok bool) {
 
 // First returns the first item of the tree in the key collating order, or
 // (zero-value, zero-value) if the tree is empty.
-func (t *tree) First() (k uint64, v *roaring.Container) {
+func (t *tree) First() (uint64, *roaring.Container) {
+	var k uint64
+	var v *roaring.Container
 	if q := t.first; q != nil {
 		q := &q.d[0]
 		k, v = q.k, q.v
 	}
-	return
+	return k, v
 }
 
 // Get returns the value associated with k and true if it exists. Otherwise Get
@@ -470,12 +473,14 @@ func (t *tree) insert(q *d, i int, k uint64, v *roaring.Container) *d {
 
 // Last returns the last item of the tree in the key collating order, or
 // (zero-value, zero-value) if the tree is empty.
-func (t *tree) Last() (k uint64, v *roaring.Container) {
+func (t *tree) Last() (uint64, *roaring.Container) {
+	var k uint64
+	var v *roaring.Container
 	if q := t.last; q != nil {
 		q := &q.d[q.c-1]
 		k, v = q.k, q.v
 	}
-	return
+	return k, v
 }
 
 // Len returns the number of items in the tree.
@@ -858,9 +863,12 @@ func (e *enumerator) Close() {
 // Next returns the currently enumerated item, if it exists and moves to the
 // next item in the key collation order. If there is no item to return, err ==
 // io.EOF is returned.
-func (e *enumerator) Next() (k uint64, v *roaring.Container, err error) {
+func (e *enumerator) Next() (uint64, *roaring.Container, error) {
+	var k uint64
+	var v *roaring.Container
+	var err error
 	if err = e.err; err != nil {
-		return
+		return 0, nil, err
 	}
 
 	if e.ver != e.t.ver {
@@ -870,12 +878,12 @@ func (e *enumerator) Next() (k uint64, v *roaring.Container, err error) {
 	}
 	if e.q == nil {
 		e.err, err = io.EOF, io.EOF
-		return
+		return 0, nil, err
 	}
 
 	if e.i >= e.q.c {
 		if err = e.next(); err != nil {
-			return
+			return 0, nil, err
 		}
 	}
 
@@ -883,7 +891,7 @@ func (e *enumerator) Next() (k uint64, v *roaring.Container, err error) {
 	k, v = i.k, i.v
 	e.k, e.hit = k, true
 	e.next()
-	return
+	return k, v, nil
 }
 
 func (e *enumerator) next() error {
@@ -906,9 +914,13 @@ func (e *enumerator) next() error {
 // Prev returns the currently enumerated item, if it exists and moves to the
 // previous item in the key collation order. If there is no item to return, err
 // == io.EOF is returned.
-func (e *enumerator) Prev() (k uint64, v *roaring.Container, err error) {
+func (e *enumerator) Prev() (uint64, *roaring.Container, error) {
+	var k uint64
+	var v *roaring.Container
+	var err error
+
 	if err = e.err; err != nil {
-		return
+		return 0, nil, err
 	}
 
 	if e.ver != e.t.ver {
@@ -918,19 +930,19 @@ func (e *enumerator) Prev() (k uint64, v *roaring.Container, err error) {
 	}
 	if e.q == nil {
 		e.err, err = io.EOF, io.EOF
-		return
+		return 0, nil, err
 	}
 
 	if !e.hit {
 		// move to previous because Seek overshoots if there's no hit
 		if err = e.prev(); err != nil {
-			return
+			return 0, nil, err
 		}
 	}
 
 	if e.i >= e.q.c {
 		if err = e.prev(); err != nil {
-			return
+			return 0, nil, err
 		}
 	}
 
@@ -938,7 +950,7 @@ func (e *enumerator) Prev() (k uint64, v *roaring.Container, err error) {
 	k, v = i.k, i.v
 	e.k, e.hit = k, true
 	e.prev()
-	return
+	return k, v, err
 }
 
 func (e *enumerator) prev() error {

enterprise/b/containers_btree.go

@@ -121,14 +121,15 @@ func (btc *bTreeContainers) GetOrCreate(key uint64) *roaring.Container {
 	return btc.lastContainer
 }
 
-func (btc *bTreeContainers) Count() (n uint64) {
+func (btc *bTreeContainers) Count() uint64 {
+	var n uint64
 	e, _ := btc.tree.Seek(0)
 	_, c, err := e.Next()
 	for err != io.EOF {
 		n += uint64(c.N())
 		_, c, err = e.Next()
 	}
-	return
+	return n
 }
 
 func (btc *bTreeContainers) Clone() roaring.Containers {

field.go

@@ -796,8 +796,8 @@ func groupCompare(a, b string, offset int) (lt, eq bool) {
 	return v < 0, v == 0
 }
 
-func (f *Field) allTimeViewsSortedByQuantum() (me []*view) {
-	me = make([]*view, len(f.viewMap), len(f.viewMap))
+func (f *Field) allTimeViewsSortedByQuantum() []*view {
+	me := make([]*view, len(f.viewMap), len(f.viewMap))
 	prefix := viewStandard + "_"
 	offset := len(viewStandard) + 1
 	i := 0
@@ -811,8 +811,8 @@ func (f *Field) allTimeViewsSortedByQuantum() (me []*view) {
 	year := strings.Index(me[0].name, "_") + 4
 	month := year + 2
 	day := month + 2
-	sort.Slice(me, func(i, j int) (lt bool) {
-		var eq bool
+	sort.Slice(me, func(i, j int) bool {
+		var eq, lt bool
 		// group by quantum from year to hour
 		if lt, eq = groupCompare(me[i].name, me[j].name, year); eq {
 			if lt, eq = groupCompare(me[i].name, me[j].name, month); eq {
@@ -821,9 +821,9 @@ func (f *Field) allTimeViewsSortedByQuantum() (me []*view) {
 				}
 			}
 		}
-		return
+		return lt
 	})
-	return
+	return me
 }
 
 // Value reads a field value for a column.

fragment.go

@@ -1162,15 +1162,16 @@ func (f *fragment) readContiguousChecksums(a *[]FragmentBlock, blockID int) (n i
 }
 
 // blockData returns bits in a block as row & column ID pairs.
-func (f *fragment) blockData(id int) (rowIDs, columnIDs []uint64) {
+func (f *fragment) blockData(id int) ([]uint64, []uint64) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
-
+	rowIDs := make([]uint64, 0)
+	columnIDs := make([]uint64, 0)
 	f.storage.ForEachRange(uint64(id)*HashBlockSize*ShardWidth, (uint64(id)+1)*HashBlockSize*ShardWidth, func(i uint64) {
 		rowIDs = append(rowIDs, i/ShardWidth)
 		columnIDs = append(columnIDs, i%ShardWidth)
 	})
-	return
+	return rowIDs, columnIDs
 }
 
 // mergeBlock compares the block's bits and computes a diff with another set of block bits.
@@ -1965,12 +1966,12 @@ func (s *fragmentSyncer) syncBlock(id int) error {
 	return nil
 }
 
-func madvise(b []byte, advice int) (err error) { // nolint: unparam
-	_, _, e1 := syscall.Syscall(syscall.SYS_MADVISE, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), uintptr(advice))
-	if e1 != 0 {
-		err = e1
+func madvise(b []byte, advice int) error { // nolint: unparam
+	_, _, err := syscall.Syscall(syscall.SYS_MADVISE, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), uintptr(advice))
+	if err != 0 {
+		return err
 	}
-	return
+	return nil
 }
 
 // pairSet is a list of equal length row and column id lists.

http/handler.go

@@ -299,10 +299,12 @@ type successResponse struct {
 
 // check determines success or failure based on the error.
 // It also returns the corresponding http status code.
-func (r *successResponse) check(err error) (statusCode int) {
+func (r *successResponse) check(err error) int {
+	var statusCode int
+
 	if err == nil {
 		r.Success = true
-		return
+		return 0
 	}
 
 	cause := errors.Cause(err)
@@ -322,7 +324,7 @@ func (r *successResponse) check(err error) (statusCode int) {
 	r.Success = false
 	r.Error = &Error{Message: cause.Error()}
 
-	return
+	return statusCode
 }
 
 // write sends a response to the http.ResponseWriter based on the success

lru/lru.go

@@ -71,15 +71,15 @@ func (c *Cache) Add(key Key, value interface{}) {
 }
 
 // Get looks up a key's value from the cache.
-func (c *Cache) Get(key Key) (value interface{}, ok bool) {
+func (c *Cache) Get(key Key) (interface{}, bool) {
 	if c.cache == nil {
-		return
+		return nil, false
 	}
 	if ele, hit := c.cache[key]; hit {
 		c.ll.MoveToFront(ele)
 		return ele.Value.(*entry).value, true
 	}
-	return
+	return nil, false
 }
 
 // remove removes the provided key from the cache.

roaring/roaring.go

@@ -1895,7 +1895,8 @@ func intersectionCountArrayRun(a, b *Container) (n int) {
 	return n
 }
 
-func intersectionCountRunRun(a, b *Container) (n int) {
+func intersectionCountRunRun(a, b *Container) int {
+	var n int
 	na, nb := len(a.runs), len(b.runs)
 	for i, j := 0, 0; i < na && j < nb; {
 		va, vb := a.runs[i], b.runs[j]
@@ -1923,7 +1924,7 @@ func intersectionCountRunRun(a, b *Container) (n int) {
 			i++
 		}
 	}
-	return
+	return n
 }
 
 func intersectionCountBitmapRun(a, b *Container) (n int) {
@@ -3144,22 +3145,20 @@ func xorArrayRun(a, b *Container) *Container {
 }
 
 // xorCompare computes first exclusive run between two runs.
-func xorCompare(x *xorstm) (r1 interval16, hasData bool) {
-	hasData = false
+func xorCompare(x *xorstm) (interval16, bool) {
+	var r1 interval16
+	var hasData bool
+
 	if !x.vaValid || !x.vbValid {
 		if x.vbValid {
 			x.vbValid = false
-			r1 = x.vb
-			hasData = true
-			return
+			return x.vb, true
 		}
 		if x.vaValid {
 			x.vaValid = false
-			r1 = x.va
-			hasData = true
-			return
+			return x.va, true
 		}
-		return
+		return r1, false
 	}
 
 	if x.va.last < x.vb.start { //va  before
@@ -3232,7 +3231,7 @@ func xorCompare(x *xorstm) (r1 interval16, hasData bool) {
 			}
 		}
 	}
-	return
+	return r1, hasData
 }
 
 //stm  is state machine used to "xor" iterate over runs.