Pull request: all: rm var shadowing, vol. 2

Updates #2803.

Squashed commit of the following:

commit bf7186378164f19ea9e21ec832526792efa2f9c3
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Mar 11 19:48:17 2021 +0300

    all: rm var shadowing, vol. 2

internal/dnsfilter/dnsfilter.go

@@ -850,7 +850,7 @@ func New(c *Config, blockFilters []Filter) *DNSFilter {
 	d.BlockedServices = bsvcs
 
 	if blockFilters != nil {
-		err := d.initFiltering(nil, blockFilters)
+		err = d.initFiltering(nil, blockFilters)
 		if err != nil {
 			log.Error("Can't initialize filtering subsystem: %s", err)
 			d.Close()

internal/dnsfilter/safebrowsing.go

@@ -229,7 +229,9 @@ func (c *sbCtx) processTXT(resp *dns.Msg) (bool, [][]byte) {
 			if !matched {
 				var hash32 [32]byte
 				copy(hash32[:], hash)
-				hashHost, ok := c.hashToHost[hash32]
+
+				var hashHost string
+				hashHost, ok = c.hashToHost[hash32]
 				if ok {
 					log.Debug("%s: matched %s by %s/%s", c.svc, c.host, hashHost, t)
 					matched = true

internal/querylog/decode.go

@@ -280,7 +280,8 @@ func decodeResultRules(dec *json.Decoder, ent *logEntry) {
 
 		i := 0
 		for {
-			keyToken, err := dec.Token()
+			var keyToken json.Token
+			keyToken, err = dec.Token()
 			if err != nil {
 				if err != io.EOF {
 					log.Debug("decodeResultRules err: %s", err)
@@ -405,7 +406,8 @@ func decodeResultDNSRewriteResult(dec *json.Decoder, ent *logEntry) {
 		// code for a longer time than planned.
 		switch key {
 		case "RCode":
-			vToken, err := dec.Token()
+			var vToken json.Token
+			vToken, err = dec.Token()
 			if err != nil {
 				if err != io.EOF {
 					log.Debug("decodeResultDNSRewriteResult err: %s", err)
@@ -418,7 +420,8 @@ func decodeResultDNSRewriteResult(dec *json.Decoder, ent *logEntry) {
 				ent.Result.DNSRewriteResult = &dnsfilter.DNSRewriteResult{}
 			}
 
-			if n, ok := vToken.(json.Number); ok {
+			var n json.Number
+			if n, ok = vToken.(json.Number); ok {
 				rcode64, _ := n.Int64()
 				ent.Result.DNSRewriteResult.RCode = rules.RCode(rcode64)
 			}

internal/querylog/http.go

@@ -150,10 +150,9 @@ func (l *queryLog) parseSearchCriteria(q url.Values, name string, ct criteriaTyp
 }
 
 // parseSearchParams - parses "searchParams" from the HTTP request's query string
-func (l *queryLog) parseSearchParams(r *http.Request) (*searchParams, error) {
-	p := newSearchParams()
+func (l *queryLog) parseSearchParams(r *http.Request) (p *searchParams, err error) {
+	p = newSearchParams()
 
-	var err error
 	q := r.URL.Query()
 	olderThan := q.Get("older_than")
 	if len(olderThan) != 0 {
@@ -163,11 +162,14 @@ func (l *queryLog) parseSearchParams(r *http.Request) (*searchParams, error) {
 		}
 	}
 
-	if limit, err := strconv.ParseInt(q.Get("limit"), 10, 64); err == nil {
-		p.limit = int(limit)
+	var limit64 int64
+	if limit64, err = strconv.ParseInt(q.Get("limit"), 10, 64); err == nil {
+		p.limit = int(limit64)
 	}
-	if offset, err := strconv.ParseInt(q.Get("offset"), 10, 64); err == nil {
-		p.offset = int(offset)
+
+	var offset64 int64
+	if offset64, err = strconv.ParseInt(q.Get("offset"), 10, 64); err == nil {
+		p.offset = int(offset64)
 
 		// If we don't use "olderThan" and use offset/limit instead, we should change the default behavior
 		// and scan all log records until we found enough log entries
@@ -180,7 +182,9 @@ func (l *queryLog) parseSearchParams(r *http.Request) (*searchParams, error) {
 	}
 
 	for k, v := range paramNames {
-		ok, c, err := l.parseSearchCriteria(q, k, v)
+		var ok bool
+		var c searchCriteria
+		ok, c, err = l.parseSearchCriteria(q, k, v)
 		if err != nil {
 			return nil, err
 		}

internal/querylog/qlogfile_test.go

@@ -225,7 +225,8 @@ func TestQLogFile_SeekTS_bad(t *testing.T) {
 			t.Run(tc.name, func(t *testing.T) {
 				assert.NotEqualValues(t, 0, tc.ts)
 
-				_, depth, err := q.SeekTS(tc.ts)
+				var depth int
+				_, depth, err = q.SeekTS(tc.ts)
 				assert.NotEmpty(t, l.num)
 				require.NotNil(t, err)
 				if tc.leq {

internal/querylog/qlogreader_test.go

@@ -112,11 +112,11 @@ func TestQLogReader_Seek(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			timestamp, err := time.Parse(time.RFC3339Nano, tc.time)
+			ts, err := time.Parse(time.RFC3339Nano, tc.time)
 			require.Nil(t, err)
 
-			err = r.SeekTS(timestamp.UnixNano())
-			assert.True(t, errors.Is(err, tc.want))
+			err = r.SeekTS(ts.UnixNano())
+			assert.True(t, errors.Is(err, tc.want), err)
 		})
 	}
 }
@@ -146,7 +146,7 @@ func TestQLogReader_ReadNext(t *testing.T) {
 			require.Nil(t, err)
 
 			for i := 1; i < tc.start; i++ {
-				_, err := r.ReadNext()
+				_, err = r.ReadNext()
 				require.Nil(t, err)
 			}
 

internal/querylog/search.go

@@ -118,8 +118,9 @@ func (l *queryLog) searchFiles(params *searchParams) ([]*logEntry, time.Time, in
 	// The idea is to make search calls faster so that the UI could handle it and show something
 	// This behavior can be overridden if "maxFileScanEntries" is set to 0
 	for total < params.maxFileScanEntries || params.maxFileScanEntries <= 0 {
-		entry, ts, err := l.readNextEntry(r, params)
-
+		var entry *logEntry
+		var ts int64
+		entry, ts, err = l.readNextEntry(r, params)
 		if err == io.EOF {
 			// there's nothing to read anymore
 			break