From d6e03d2368e9d1fa11ed19f9a4d54e4c578d727c Mon Sep 17 00:00:00 2001
From: Zach Ramsay <zach.ramsay@gmail.com>
Date: Fri, 22 Sep 2017 11:42:29 -0400
Subject: [PATCH 01/26] linting: add to Makefile & do some fixes

---
 Makefile                    | 43 ++++++++++++++++++++++++++++++++++++-
 autofile/autofile_test.go   |  4 +++-
 autofile/group.go           |  4 +---
 autofile/group_test.go      |  3 +--
 autofile/sighup_watcher.go  |  2 +-
 cli/flags/log_level_test.go |  2 --
 clist/clist_test.go         |  6 ++++--
 common/cmap.go              |  4 ++--
 common/errors.go            |  2 +-
 common/http_test.go         |  2 +-
 common/os.go                | 10 +++------
 common/string.go            |  5 +----
 events/events_test.go       | 15 ++++++-------
 flowrate/io_test.go         |  5 +----
 log/filter_test.go          |  6 ++----
 log/tmfmt_logger.go         |  7 +++---
 log/tracing_logger_test.go  |  3 +--
 merkle/simple_tree.go       |  3 ++-
 process/util.go             |  4 ++--
 pubsub/query/query.peg.go   |  3 +++
 20 files changed, 82 insertions(+), 51 deletions(-)

diff --git a/Makefile b/Makefile
index 8e43dd11a..ba164ec1d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,15 @@
 .PHONY: all test get_vendor_deps ensure_tools
 
 GOTOOLS = \
-	github.com/Masterminds/glide
+	github.com/Masterminds/glide \
+	github.com/alecthomas/gometalinter
+
 REPO:=github.com/tendermint/tmlibs
 
 all: test
 
+NOVENDOR = go list github.com/tendermint/tmlibs/... | grep -v /vendor/
+
 test:
 	go test `glide novendor`
 
@@ -16,3 +20,40 @@ get_vendor_deps: ensure_tools
 
 ensure_tools:
 	go get $(GOTOOLS)
+
+metalinter: ensure_tools
+	@gometalinter --install
+	gometalinter --vendor --deadline=600s --enable-all --disable=lll ./...
+
+metalinter_test: ensure_tools
+	@gometalinter --install
+	gometalinter --vendor --deadline=600s --disable-all  \
+		--enable=deadcode \
+		--enable=gas \
+		--enable=goconst \
+		--enable=goimports \
+		--enable=gosimple \
+		--enable=gotype \
+	 	--enable=ineffassign \
+		--enable=megacheck \
+	 	--enable=misspell \
+	   	--enable=staticcheck \
+		--enable=safesql \
+	   	--enable=structcheck \
+	   	--enable=unconvert \
+		--enable=unused \
+	   	--enable=varcheck \
+		--enable=vetshadow \
+	   	--enable=interfacer \
+	   	--enable=unparam \
+		--enable=vet \
+		./...
+
+		#--enable=aligncheck \
+		#--enable=dupl \
+		#--enable=errcheck \
+		#--enable=gocyclo \
+		#--enable=golint \ <== comments on anything exported
+	   	#--enable=interfacer \
+	   	#--enable=unparam \
+		#--enable=vet \
diff --git a/autofile/autofile_test.go b/autofile/autofile_test.go
index 8f8017e1b..c7aa93beb 100644
--- a/autofile/autofile_test.go
+++ b/autofile/autofile_test.go
@@ -1,12 +1,14 @@
+// nolint: goimports
 package autofile
 
 import (
-	. "github.com/tendermint/tmlibs/common"
 	"os"
 	"sync/atomic"
 	"syscall"
 	"testing"
 	"time"
+
+	. "github.com/tendermint/tmlibs/common"
 )
 
 func TestSIGHUP(t *testing.T) {
diff --git a/autofile/group.go b/autofile/group.go
index ce3e30009..689b1cb92 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -107,7 +107,6 @@ func (g *Group) OnStart() error {
 func (g *Group) OnStop() {
 	g.BaseService.OnStop()
 	g.ticker.Stop()
-	return
 }
 
 func (g *Group) SetHeadSizeLimit(limit int64) {
@@ -568,8 +567,7 @@ func (gr *GroupReader) ReadLine() (string, error) {
 		bytesRead, err := gr.curReader.ReadBytes('\n')
 		if err == io.EOF {
 			// Open the next file
-			err := gr.openFile(gr.curIndex + 1)
-			if err != nil {
+			if err := gr.openFile(gr.curIndex + 1); err != nil {
 				return "", err
 			}
 			if len(bytesRead) > 0 && bytesRead[len(bytesRead)-1] == byte('\n') {
diff --git a/autofile/group_test.go b/autofile/group_test.go
index 92e259701..91c6a0bbd 100644
--- a/autofile/group_test.go
+++ b/autofile/group_test.go
@@ -100,8 +100,7 @@ func TestCheckHeadSizeLimit(t *testing.T) {
 
 	// Write 1000 bytes 999 times.
 	for i := 0; i < 999; i++ {
-		err := g.WriteLine(RandStr(999))
-		if err != nil {
+		if err := g.WriteLine(RandStr(999)); err != nil {
 			t.Fatal("Error appending to head", err)
 		}
 	}
diff --git a/autofile/sighup_watcher.go b/autofile/sighup_watcher.go
index facc238d5..56fbd4d86 100644
--- a/autofile/sighup_watcher.go
+++ b/autofile/sighup_watcher.go
@@ -22,7 +22,7 @@ func initSighupWatcher() {
 	signal.Notify(c, syscall.SIGHUP)
 
 	go func() {
-		for _ = range c {
+		for range c {
 			sighupWatchers.closeAll()
 			atomic.AddInt32(&sighupCounter, 1)
 		}
diff --git a/cli/flags/log_level_test.go b/cli/flags/log_level_test.go
index 458a9e24d..faf9b19db 100644
--- a/cli/flags/log_level_test.go
+++ b/cli/flags/log_level_test.go
@@ -49,8 +49,6 @@ func TestParseLogLevel(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		logger = logger
-
 		buf.Reset()
 
 		logger.With("module", "wire").Debug("Kingpin")
diff --git a/clist/clist_test.go b/clist/clist_test.go
index ab5cf4b26..2063cf465 100644
--- a/clist/clist_test.go
+++ b/clist/clist_test.go
@@ -55,6 +55,7 @@ func TestSmall(t *testing.T) {
 This test is quite hacky because it relies on SetFinalizer
 which isn't guaranteed to run at all.
 */
+// nolint: megacheck
 func _TestGCFifo(t *testing.T) {
 
 	const numElements = 1000000
@@ -102,6 +103,7 @@ func _TestGCFifo(t *testing.T) {
 This test is quite hacky because it relies on SetFinalizer
 which isn't guaranteed to run at all.
 */
+// nolint: megacheck
 func _TestGCRandom(t *testing.T) {
 
 	const numElements = 1000000
@@ -132,7 +134,7 @@ func _TestGCRandom(t *testing.T) {
 	for _, i := range rand.Perm(numElements) {
 		el := els[i]
 		l.Remove(el)
-		el = el.Next()
+		_ = el.Next()
 	}
 
 	runtime.GC()
@@ -153,7 +155,7 @@ func TestScanRightDeleteRandom(t *testing.T) {
 	l := New()
 	stop := make(chan struct{})
 
-	els := make([]*CElement, numElements, numElements)
+	els := make([]*CElement, numElements)
 	for i := 0; i < numElements; i++ {
 		el := l.PushBack(i)
 		els[i] = el
diff --git a/common/cmap.go b/common/cmap.go
index 5de6fa2fa..e2a140dd0 100644
--- a/common/cmap.go
+++ b/common/cmap.go
@@ -10,7 +10,7 @@ type CMap struct {
 
 func NewCMap() *CMap {
 	return &CMap{
-		m: make(map[string]interface{}, 0),
+		m: make(map[string]interface{}),
 	}
 }
 
@@ -48,7 +48,7 @@ func (cm *CMap) Size() int {
 func (cm *CMap) Clear() {
 	cm.l.Lock()
 	defer cm.l.Unlock()
-	cm.m = make(map[string]interface{}, 0)
+	cm.m = make(map[string]interface{})
 }
 
 func (cm *CMap) Values() []interface{} {
diff --git a/common/errors.go b/common/errors.go
index 3a1b09542..039342a67 100644
--- a/common/errors.go
+++ b/common/errors.go
@@ -21,7 +21,7 @@ func (se StackError) Error() string {
 // panic wrappers
 
 // A panic resulting from a sanity check means there is a programmer error
-// and some gaurantee is not satisfied.
+// and some guarantee is not satisfied.
 func PanicSanity(v interface{}) {
 	panic(Fmt("Panicked on a Sanity Check: %v", v))
 }
diff --git a/common/http_test.go b/common/http_test.go
index 73761fb1e..4272f6062 100644
--- a/common/http_test.go
+++ b/common/http_test.go
@@ -95,7 +95,7 @@ func TestWriteCode(t *testing.T) {
 		common.WriteCode(w, &marshalFailer{}, code)
 		wantCode := http.StatusBadRequest
 		assert.Equal(t, w.Code, wantCode, "#%d", i)
-		assert.True(t, strings.Contains(string(w.Body.Bytes()), errFooFailed.Error()),
+		assert.True(t, strings.Contains(w.Body.String(), errFooFailed.Error()),
 			"#%d: expected %q in the error message", i, errFooFailed)
 	}
 }
diff --git a/common/os.go b/common/os.go
index 9c2bda508..8b7143f5a 100644
--- a/common/os.go
+++ b/common/os.go
@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/signal"
 	"strings"
+	"syscall"
 )
 
 var (
@@ -17,7 +18,7 @@ var (
 func TrapSignal(cb func()) {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
-	signal.Notify(c, os.Kill)
+	signal.Notify(c, syscall.SIGTERM)
 	go func() {
 		for sig := range c {
 			fmt.Printf("captured %v, exiting...\n", sig)
@@ -83,12 +84,7 @@ func MustReadFile(filePath string) []byte {
 }
 
 func WriteFile(filePath string, contents []byte, mode os.FileMode) error {
-	err := ioutil.WriteFile(filePath, contents, mode)
-	if err != nil {
-		return err
-	}
-	// fmt.Printf("File written to %v.\n", filePath)
-	return nil
+	return ioutil.WriteFile(filePath, contents, mode)
 }
 
 func MustWriteFile(filePath string, contents []byte, mode os.FileMode) {
diff --git a/common/string.go b/common/string.go
index 2818f5ed5..1ab91f15a 100644
--- a/common/string.go
+++ b/common/string.go
@@ -31,10 +31,7 @@ func LeftPadString(s string, totalLength int) string {
 func IsHex(s string) bool {
 	if len(s) > 2 && s[:2] == "0x" {
 		_, err := hex.DecodeString(s[2:])
-		if err != nil {
-			return false
-		}
-		return true
+		return err == nil
 	}
 	return false
 }
diff --git a/events/events_test.go b/events/events_test.go
index c1b48b16f..dee50e5bd 100644
--- a/events/events_test.go
+++ b/events/events_test.go
@@ -14,7 +14,7 @@ import (
 func TestAddListenerForEventFireOnce(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	messages := make(chan EventData)
@@ -34,7 +34,7 @@ func TestAddListenerForEventFireOnce(t *testing.T) {
 func TestAddListenerForEventFireMany(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	doneSum := make(chan uint64)
@@ -63,7 +63,7 @@ func TestAddListenerForEventFireMany(t *testing.T) {
 func TestAddListenerForDifferentEvents(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	doneSum := make(chan uint64)
@@ -108,7 +108,7 @@ func TestAddListenerForDifferentEvents(t *testing.T) {
 func TestAddDifferentListenerForDifferentEvents(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	doneSum1 := make(chan uint64)
@@ -168,7 +168,7 @@ func TestAddDifferentListenerForDifferentEvents(t *testing.T) {
 func TestAddAndRemoveListener(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	doneSum1 := make(chan uint64)
@@ -213,7 +213,7 @@ func TestAddAndRemoveListener(t *testing.T) {
 func TestRemoveListener(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	count := 10
@@ -266,7 +266,7 @@ func TestRemoveListener(t *testing.T) {
 func TestRemoveListenersAsync(t *testing.T) {
 	evsw := NewEventSwitch()
 	started, err := evsw.Start()
-	if started == false || err != nil {
+	if !started || err != nil {
 		t.Errorf("Failed to start EventSwitch, error: %v", err)
 	}
 	doneSum1 := make(chan uint64)
@@ -377,5 +377,4 @@ func fireEvents(evsw EventSwitch, event string, doneChan chan uint64,
 	}
 	doneChan <- sentSum
 	close(doneChan)
-	return
 }
diff --git a/flowrate/io_test.go b/flowrate/io_test.go
index 6d4934a8a..db40337c9 100644
--- a/flowrate/io_test.go
+++ b/flowrate/io_test.go
@@ -171,10 +171,7 @@ func statusesAreEqual(s1 *Status, s2 *Status) bool {
 }
 
 func durationsAreEqual(d1 time.Duration, d2 time.Duration, maxDeviation time.Duration) bool {
-	if d2-d1 <= maxDeviation {
-		return true
-	}
-	return false
+	return d2-d1 <= maxDeviation
 }
 
 func ratesAreEqual(r1 int64, r2 int64, maxDeviation int64) bool {
diff --git a/log/filter_test.go b/log/filter_test.go
index fafafacb0..8d8b3b27c 100644
--- a/log/filter_test.go
+++ b/log/filter_test.go
@@ -73,8 +73,7 @@ func TestVariousLevels(t *testing.T) {
 func TestLevelContext(t *testing.T) {
 	var buf bytes.Buffer
 
-	var logger log.Logger
-	logger = log.NewTMJSONLogger(&buf)
+	logger := log.NewTMJSONLogger(&buf)
 	logger = log.NewFilter(logger, log.AllowError())
 	logger = logger.With("context", "value")
 
@@ -93,8 +92,7 @@ func TestLevelContext(t *testing.T) {
 func TestVariousAllowWith(t *testing.T) {
 	var buf bytes.Buffer
 
-	var logger log.Logger
-	logger = log.NewTMJSONLogger(&buf)
+	logger := log.NewTMJSONLogger(&buf)
 
 	logger1 := log.NewFilter(logger, log.AllowError(), log.AllowInfoWith("context", "value"))
 	logger1.With("context", "value").Info("foo", "bar", "baz")
diff --git a/log/tmfmt_logger.go b/log/tmfmt_logger.go
index 14028d756..2b464a6b0 100644
--- a/log/tmfmt_logger.go
+++ b/log/tmfmt_logger.go
@@ -49,9 +49,10 @@ func (l tmfmtLogger) Log(keyvals ...interface{}) error {
 	enc.Reset()
 	defer tmfmtEncoderPool.Put(enc)
 
+	const unknown = "unknown"
 	lvl := "none"
-	msg := "unknown"
-	module := "unknown"
+	msg := unknown
+	module := unknown
 
 	// indexes of keys to skip while encoding later
 	excludeIndexes := make([]int, 0)
@@ -90,7 +91,7 @@ func (l tmfmtLogger) Log(keyvals ...interface{}) error {
 	//     Stopping ...					- message
 	enc.buf.WriteString(fmt.Sprintf("%c[%s] %-44s ", lvl[0]-32, time.Now().UTC().Format("01-02|15:04:05.000"), msg))
 
-	if module != "unknown" {
+	if module != unknown {
 		enc.buf.WriteString("module=" + module + " ")
 	}
 
diff --git a/log/tracing_logger_test.go b/log/tracing_logger_test.go
index 584b34bef..6b0838ca8 100644
--- a/log/tracing_logger_test.go
+++ b/log/tracing_logger_test.go
@@ -14,8 +14,7 @@ import (
 func TestTracingLogger(t *testing.T) {
 	var buf bytes.Buffer
 
-	var logger log.Logger
-	logger = log.NewTMJSONLogger(&buf)
+	logger := log.NewTMJSONLogger(&buf)
 
 	logger1 := log.NewTracingLogger(logger)
 	err1 := errors.New("Courage is grace under pressure.")
diff --git a/merkle/simple_tree.go b/merkle/simple_tree.go
index b5520f723..b373743fc 100644
--- a/merkle/simple_tree.go
+++ b/merkle/simple_tree.go
@@ -22,6 +22,7 @@ For larger datasets, use IAVLTree.
 
 */
 
+// nolint: goimports
 package merkle
 
 import (
@@ -31,8 +32,8 @@ import (
 
 	"golang.org/x/crypto/ripemd160"
 
-	. "github.com/tendermint/tmlibs/common"
 	"github.com/tendermint/go-wire"
+	. "github.com/tendermint/tmlibs/common"
 )
 
 func SimpleHashFromTwoHashes(left []byte, right []byte) []byte {
diff --git a/process/util.go b/process/util.go
index b3e0aef11..24cf35280 100644
--- a/process/util.go
+++ b/process/util.go
@@ -15,8 +15,8 @@ func Run(dir string, command string, args []string) (string, bool, error) {
 	<-proc.WaitCh
 
 	if proc.ExitState.Success() {
-		return string(outFile.Bytes()), true, nil
+		return outFile.String(), true, nil
 	} else {
-		return string(outFile.Bytes()), false, nil
+		return outFile.String(), false, nil
 	}
 }
diff --git a/pubsub/query/query.peg.go b/pubsub/query/query.peg.go
index 37ce75cd9..8c3e83efc 100644
--- a/pubsub/query/query.peg.go
+++ b/pubsub/query/query.peg.go
@@ -1,3 +1,6 @@
+// nolint: megacheck
+// nolint: varcheck
+// nolint: deadcode
 package query
 
 import (

From 3c57c24921f8197343cf6e592de31b5fd31509cc Mon Sep 17 00:00:00 2001
From: Zach Ramsay <zach.ramsay@gmail.com>
Date: Fri, 22 Sep 2017 12:14:27 -0400
Subject: [PATCH 02/26] linting: next round  of fixes

---
 Makefile                  | 1 -
 autofile/group.go         | 4 ++--
 autofile/group_test.go    | 8 +++-----
 common/service.go         | 2 +-
 db/c_level_db_test.go     | 2 +-
 db/go_level_db_test.go    | 2 +-
 pubsub/query/query.peg.go | 4 +---
 7 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/Makefile b/Makefile
index ba164ec1d..6b2c7463a 100644
--- a/Makefile
+++ b/Makefile
@@ -45,7 +45,6 @@ metalinter_test: ensure_tools
 	   	--enable=varcheck \
 		--enable=vetshadow \
 	   	--enable=interfacer \
-	   	--enable=unparam \
 		--enable=vet \
 		./...
 
diff --git a/autofile/group.go b/autofile/group.go
index 689b1cb92..eedb67b50 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -567,8 +567,8 @@ func (gr *GroupReader) ReadLine() (string, error) {
 		bytesRead, err := gr.curReader.ReadBytes('\n')
 		if err == io.EOF {
 			// Open the next file
-			if err := gr.openFile(gr.curIndex + 1); err != nil {
-				return "", err
+			if err1 := gr.openFile(gr.curIndex + 1); err1 != nil {
+				return "", err1
 			}
 			if len(bytesRead) > 0 && bytesRead[len(bytesRead)-1] == byte('\n') {
 				return linePrefix + string(bytesRead[:len(bytesRead)-1]), nil
diff --git a/autofile/group_test.go b/autofile/group_test.go
index 91c6a0bbd..0cfcef72f 100644
--- a/autofile/group_test.go
+++ b/autofile/group_test.go
@@ -77,8 +77,7 @@ func TestCheckHeadSizeLimit(t *testing.T) {
 	assertGroupInfo(t, g.ReadGroupInfo(), 0, 0, 999000, 999000)
 
 	// Write 1000 more bytes.
-	err := g.WriteLine(RandStr(999))
-	if err != nil {
+	if err := g.WriteLine(RandStr(999)); err != nil {
 		t.Fatal("Error appending to head", err)
 	}
 	g.Flush()
@@ -88,8 +87,7 @@ func TestCheckHeadSizeLimit(t *testing.T) {
 	assertGroupInfo(t, g.ReadGroupInfo(), 0, 1, 1000000, 0)
 
 	// Write 1000 more bytes.
-	err = g.WriteLine(RandStr(999))
-	if err != nil {
+	if err := g.WriteLine(RandStr(999)); err != nil {
 		t.Fatal("Error appending to head", err)
 	}
 	g.Flush()
@@ -112,7 +110,7 @@ func TestCheckHeadSizeLimit(t *testing.T) {
 	assertGroupInfo(t, g.ReadGroupInfo(), 0, 2, 2000000, 0)
 
 	// Write 1000 more bytes.
-	_, err = g.Head.Write([]byte(RandStr(999) + "\n"))
+	_, err := g.Head.Write([]byte(RandStr(999) + "\n"))
 	if err != nil {
 		t.Fatal("Error appending to head", err)
 	}
diff --git a/common/service.go b/common/service.go
index 71fc03cb9..5ac386316 100644
--- a/common/service.go
+++ b/common/service.go
@@ -151,7 +151,7 @@ func (bs *BaseService) Reset() (bool, error) {
 		return false, nil
 	}
 	// never happens
-	return false, nil
+	return false, nil // nolint: vet
 }
 
 // Implements Service
diff --git a/db/c_level_db_test.go b/db/c_level_db_test.go
index 0ee6d6414..e7336cc5f 100644
--- a/db/c_level_db_test.go
+++ b/db/c_level_db_test.go
@@ -50,7 +50,7 @@ func BenchmarkRandomReadsWrites2(b *testing.B) {
 			//fmt.Printf("Get %X -> %X\n", idxBytes, valBytes)
 			if val == 0 {
 				if !bytes.Equal(valBytes, nil) {
-					b.Errorf("Expected %X for %v, got %X",
+					b.Errorf("Expected %v for %v, got %X",
 						nil, idx, valBytes)
 					break
 				}
diff --git a/db/go_level_db_test.go b/db/go_level_db_test.go
index 0603b2d4f..2cd3192c3 100644
--- a/db/go_level_db_test.go
+++ b/db/go_level_db_test.go
@@ -49,7 +49,7 @@ func BenchmarkRandomReadsWrites(b *testing.B) {
 			//fmt.Printf("Get %X -> %X\n", idxBytes, valBytes)
 			if val == 0 {
 				if !bytes.Equal(valBytes, nil) {
-					b.Errorf("Expected %X for %v, got %X",
+					b.Errorf("Expected %v for %v, got %X",
 						nil, idx, valBytes)
 					break
 				}
diff --git a/pubsub/query/query.peg.go b/pubsub/query/query.peg.go
index 8c3e83efc..c86e4a47f 100644
--- a/pubsub/query/query.peg.go
+++ b/pubsub/query/query.peg.go
@@ -1,6 +1,4 @@
-// nolint: megacheck
-// nolint: varcheck
-// nolint: deadcode
+// nolint
 package query
 
 import (

From 2681f32bddcc061e8ae062734404e73cbe6ea5d0 Mon Sep 17 00:00:00 2001
From: Zach Ramsay <zach.ramsay@gmail.com>
Date: Fri, 22 Sep 2017 12:35:52 -0400
Subject: [PATCH 03/26] circle: add metalinter to test

---
 Makefile   | 4 +---
 circle.yml | 2 +-
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 6b2c7463a..902197e77 100644
--- a/Makefile
+++ b/Makefile
@@ -35,6 +35,7 @@ metalinter_test: ensure_tools
 		--enable=gosimple \
 		--enable=gotype \
 	 	--enable=ineffassign \
+	   	--enable=interfacer \
 		--enable=megacheck \
 	 	--enable=misspell \
 	   	--enable=staticcheck \
@@ -44,7 +45,6 @@ metalinter_test: ensure_tools
 		--enable=unused \
 	   	--enable=varcheck \
 		--enable=vetshadow \
-	   	--enable=interfacer \
 		--enable=vet \
 		./...
 
@@ -53,6 +53,4 @@ metalinter_test: ensure_tools
 		#--enable=errcheck \
 		#--enable=gocyclo \
 		#--enable=golint \ <== comments on anything exported
-	   	#--enable=interfacer \
 	   	#--enable=unparam \
-		#--enable=vet \
diff --git a/circle.yml b/circle.yml
index 23ac4bd9f..8e3ad168b 100644
--- a/circle.yml
+++ b/circle.yml
@@ -18,4 +18,4 @@ dependencies:
 test:
   override:
     - "go version"
-    - "cd $PROJECT_PATH && make get_vendor_deps && make test"
+    - "cd $PROJECT_PATH && make get_vendor_deps && make metalinter_test && make test"

From 296d2235455dc62627d9c3feaf31306497fd4aae Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@cloudhead.io>
Date: Thu, 28 Sep 2017 17:26:24 +0200
Subject: [PATCH 04/26] Add Release & Error methods to Iterator

We need this to properly support LevelDB backend, which needs
to be released if we don't want to leak memory.
---
 db/db.go     |  5 ++++-
 db/mem_db.go | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/db/db.go b/db/db.go
index aa8ff48a8..51283ac2a 100644
--- a/db/db.go
+++ b/db/db.go
@@ -10,10 +10,10 @@ type DB interface {
 	DeleteSync([]byte)
 	Close()
 	NewBatch() Batch
+	Iterator() Iterator
 
 	// For debugging
 	Print()
-	Iterator() Iterator
 	Stats() map[string]string
 }
 
@@ -28,6 +28,9 @@ type Iterator interface {
 
 	Key() []byte
 	Value() []byte
+
+	Release()
+	Error() error
 }
 
 //-----------------------------------------------------------------------------
diff --git a/db/mem_db.go b/db/mem_db.go
index db40227e8..04d48cac0 100644
--- a/db/mem_db.go
+++ b/db/mem_db.go
@@ -97,6 +97,16 @@ func (it *memDBIterator) Value() []byte {
 	return it.db.Get(it.Key())
 }
 
+func (it *memDBIterator) Release() {
+	it.db = nil
+	it.keys = nil
+	return
+}
+
+func (it *memDBIterator) Error() error {
+	return nil
+}
+
 func (db *MemDB) Iterator() Iterator {
 	it := newMemDBIterator()
 	it.db = db

From 219d4e8427b2ddb0e9146ca7319bce2e1f22a6ce Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@cloudhead.io>
Date: Thu, 28 Sep 2017 17:35:01 +0200
Subject: [PATCH 05/26] Add IteratorPrefix method to Iterator

---
 db/db.go          | 1 +
 db/go_level_db.go | 5 +++++
 db/mem_db.go      | 9 ++++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/db/db.go b/db/db.go
index 51283ac2a..8156c1e92 100644
--- a/db/db.go
+++ b/db/db.go
@@ -11,6 +11,7 @@ type DB interface {
 	Close()
 	NewBatch() Batch
 	Iterator() Iterator
+	IteratorPrefix([]byte) Iterator
 
 	// For debugging
 	Print()
diff --git a/db/go_level_db.go b/db/go_level_db.go
index 54ae1149f..31c85ce86 100644
--- a/db/go_level_db.go
+++ b/db/go_level_db.go
@@ -7,6 +7,7 @@ import (
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/errors"
 	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
 
 	. "github.com/tendermint/tmlibs/common"
 )
@@ -119,6 +120,10 @@ func (db *GoLevelDB) Iterator() Iterator {
 	return db.db.NewIterator(nil, nil)
 }
 
+func (db *GoLevelDB) IteratorPrefix(prefix []byte) Iterator {
+	return db.db.NewIterator(util.BytesPrefix(prefix), nil)
+}
+
 func (db *GoLevelDB) NewBatch() Batch {
 	batch := new(leveldb.Batch)
 	return &goLevelDBBatch{db, batch}
diff --git a/db/mem_db.go b/db/mem_db.go
index 04d48cac0..561633291 100644
--- a/db/mem_db.go
+++ b/db/mem_db.go
@@ -2,6 +2,7 @@ package db
 
 import (
 	"fmt"
+	"strings"
 	"sync"
 )
 
@@ -108,6 +109,10 @@ func (it *memDBIterator) Error() error {
 }
 
 func (db *MemDB) Iterator() Iterator {
+	return db.IteratorPrefix([]byte{})
+}
+
+func (db *MemDB) IteratorPrefix(prefix []byte) Iterator {
 	it := newMemDBIterator()
 	it.db = db
 	it.last = -1
@@ -117,7 +122,9 @@ func (db *MemDB) Iterator() Iterator {
 
 	// unfortunately we need a copy of all of the keys
 	for key, _ := range db.db {
-		it.keys = append(it.keys, key)
+		if strings.HasPrefix(key, string(prefix)) {
+			it.keys = append(it.keys, key)
+		}
 	}
 	return it
 }

From e9e6ec3a2c22b3139c5787dd3e6c8a61960ec522 Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@cloudhead.io>
Date: Thu, 28 Sep 2017 17:43:47 +0200
Subject: [PATCH 06/26] Implement Key/Value on Iterator for GoLevelDB

This is needed because leveldb reuses the keys on each iteration.
In our wrapper, we copy the key/value so that it is safe to store.
---
 db/go_level_db.go | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/db/go_level_db.go b/db/go_level_db.go
index 31c85ce86..2d2ba44e3 100644
--- a/db/go_level_db.go
+++ b/db/go_level_db.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 	"github.com/syndtr/goleveldb/leveldb/util"
 
@@ -116,12 +117,32 @@ func (db *GoLevelDB) Stats() map[string]string {
 	return stats
 }
 
+type goLevelDBIterator struct {
+	iterator.Iterator
+}
+
+func (it *goLevelDBIterator) Key() []byte {
+	key := it.Key()
+	k := make([]byte, len(key))
+	copy(k, key)
+
+	return k
+}
+
+func (it *goLevelDBIterator) Value() []byte {
+	val := it.Value()
+	v := make([]byte, len(val))
+	copy(v, val)
+
+	return v
+}
+
 func (db *GoLevelDB) Iterator() Iterator {
-	return db.db.NewIterator(nil, nil)
+	return &goLevelDBIterator{db.db.NewIterator(nil, nil)}
 }
 
 func (db *GoLevelDB) IteratorPrefix(prefix []byte) Iterator {
-	return db.db.NewIterator(util.BytesPrefix(prefix), nil)
+	return &goLevelDBIterator{db.db.NewIterator(util.BytesPrefix(prefix), nil)}
 }
 
 func (db *GoLevelDB) NewBatch() Batch {

From cf49ba876fe8e7734acccd4c29289b77ea5829a5 Mon Sep 17 00:00:00 2001
From: Zach Ramsay <zach.ramsay@gmail.com>
Date: Tue, 3 Oct 2017 12:18:21 -0400
Subject: [PATCH 07/26] linter: couple fixes

---
 Makefile                  |  4 ++--
 autofile/autofile_test.go | 21 ++++++++-------------
 common/os.go              |  3 +--
 common/service.go         | 16 +++++++---------
 merkle/simple_tree.go     |  1 -
 5 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/Makefile b/Makefile
index 902197e77..25773ed36 100644
--- a/Makefile
+++ b/Makefile
@@ -31,9 +31,7 @@ metalinter_test: ensure_tools
 		--enable=deadcode \
 		--enable=gas \
 		--enable=goconst \
-		--enable=goimports \
 		--enable=gosimple \
-		--enable=gotype \
 	 	--enable=ineffassign \
 	   	--enable=interfacer \
 		--enable=megacheck \
@@ -52,5 +50,7 @@ metalinter_test: ensure_tools
 		#--enable=dupl \
 		#--enable=errcheck \
 		#--enable=gocyclo \
+		#--enable=goimports \
 		#--enable=golint \ <== comments on anything exported
+		#--enable=gotype \
 	   	#--enable=unparam \
diff --git a/autofile/autofile_test.go b/autofile/autofile_test.go
index c7aa93beb..05152219c 100644
--- a/autofile/autofile_test.go
+++ b/autofile/autofile_test.go
@@ -1,4 +1,3 @@
-// nolint: goimports
 package autofile
 
 import (
@@ -8,19 +7,18 @@ import (
 	"testing"
 	"time"
 
-	. "github.com/tendermint/tmlibs/common"
+	cmn "github.com/tendermint/tmlibs/common"
 )
 
 func TestSIGHUP(t *testing.T) {
 
 	// First, create an AutoFile writing to a tempfile dir
-	file, name := Tempfile("sighup_test")
-	err := file.Close()
-	if err != nil {
+	file, name := cmn.Tempfile("sighup_test")
+	if err := file.Close(); err != nil {
 		t.Fatalf("Error creating tempfile: %v", err)
 	}
 	// Here is the actual AutoFile
-	af, err := OpenAutoFile(name)
+	af, err := cmn.OpenAutoFile(name)
 	if err != nil {
 		t.Fatalf("Error creating autofile: %v", err)
 	}
@@ -36,8 +34,7 @@ func TestSIGHUP(t *testing.T) {
 	}
 
 	// Move the file over
-	err = os.Rename(name, name+"_old")
-	if err != nil {
+	if err := os.Rename(name, name+"_old"); err != nil {
 		t.Fatalf("Error moving autofile: %v", err)
 	}
 
@@ -59,17 +56,15 @@ func TestSIGHUP(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Error writing to autofile: %v", err)
 	}
-	err = af.Close()
-	if err != nil {
+	if err := af.Close(); err != nil {
 		t.Fatalf("Error closing autofile")
 	}
 
 	// Both files should exist
-	if body := MustReadFile(name + "_old"); string(body) != "Line 1\nLine 2\n" {
+	if body := cmn.MustReadFile(name + "_old"); string(body) != "Line 1\nLine 2\n" {
 		t.Errorf("Unexpected body %s", body)
 	}
-	if body := MustReadFile(name); string(body) != "Line 3\nLine 4\n" {
+	if body := cmn.MustReadFile(name); string(body) != "Line 3\nLine 4\n" {
 		t.Errorf("Unexpected body %s", body)
 	}
-
 }
diff --git a/common/os.go b/common/os.go
index 8b7143f5a..19aa479f9 100644
--- a/common/os.go
+++ b/common/os.go
@@ -8,7 +8,6 @@ import (
 	"os"
 	"os/signal"
 	"strings"
-	"syscall"
 )
 
 var (
@@ -18,7 +17,7 @@ var (
 func TrapSignal(cb func()) {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
-	signal.Notify(c, syscall.SIGTERM)
+	signal.Notify(c, os.Kill) // nolint: megacheck
 	go func() {
 		for sig := range c {
 			fmt.Printf("captured %v, exiting...\n", sig)
diff --git a/common/service.go b/common/service.go
index 5ac386316..2d86baafe 100644
--- a/common/service.go
+++ b/common/service.go
@@ -140,18 +140,16 @@ func (bs *BaseService) OnStop() {}
 
 // Implements Service
 func (bs *BaseService) Reset() (bool, error) {
-	if atomic.CompareAndSwapUint32(&bs.stopped, 1, 0) {
-		// whether or not we've started, we can reset
-		atomic.CompareAndSwapUint32(&bs.started, 1, 0)
-
-		bs.Quit = make(chan struct{})
-		return true, bs.impl.OnReset()
-	} else {
+	if stopped := atomic.CompareAndSwapUint32(&bs.stopped, 1, 0); !stopped {
 		bs.Logger.Debug(Fmt("Can't reset %v. Not stopped", bs.name), "impl", bs.impl)
 		return false, nil
 	}
-	// never happens
-	return false, nil // nolint: vet
+
+	// whether or not we've started, we can reset
+	atomic.CompareAndSwapUint32(&bs.started, 1, 0)
+
+	bs.Quit = make(chan struct{})
+	return true, bs.impl.OnReset()
 }
 
 // Implements Service
diff --git a/merkle/simple_tree.go b/merkle/simple_tree.go
index b373743fc..8106246d6 100644
--- a/merkle/simple_tree.go
+++ b/merkle/simple_tree.go
@@ -22,7 +22,6 @@ For larger datasets, use IAVLTree.
 
 */
 
-// nolint: goimports
 package merkle
 
 import (

From c8805fd7deb52c9565f1f0c5e465b480dcf13f2c Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Wed, 4 Oct 2017 00:13:58 -0400
Subject: [PATCH 08/26] metalinter fixes from review

---
 autofile/autofile_test.go | 5 +++--
 common/os.go              | 4 ++--
 common/service.go         | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/autofile/autofile_test.go b/autofile/autofile_test.go
index 05152219c..8f453dd07 100644
--- a/autofile/autofile_test.go
+++ b/autofile/autofile_test.go
@@ -18,7 +18,7 @@ func TestSIGHUP(t *testing.T) {
 		t.Fatalf("Error creating tempfile: %v", err)
 	}
 	// Here is the actual AutoFile
-	af, err := cmn.OpenAutoFile(name)
+	af, err := OpenAutoFile(name)
 	if err != nil {
 		t.Fatalf("Error creating autofile: %v", err)
 	}
@@ -34,7 +34,8 @@ func TestSIGHUP(t *testing.T) {
 	}
 
 	// Move the file over
-	if err := os.Rename(name, name+"_old"); err != nil {
+	err = os.Rename(name, name+"_old")
+	if err != nil {
 		t.Fatalf("Error moving autofile: %v", err)
 	}
 
diff --git a/common/os.go b/common/os.go
index 19aa479f9..625d6ae16 100644
--- a/common/os.go
+++ b/common/os.go
@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/signal"
 	"strings"
+	"syscall"
 )
 
 var (
@@ -16,8 +17,7 @@ var (
 
 func TrapSignal(cb func()) {
 	c := make(chan os.Signal, 1)
-	signal.Notify(c, os.Interrupt)
-	signal.Notify(c, os.Kill) // nolint: megacheck
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
 	go func() {
 		for sig := range c {
 			fmt.Printf("captured %v, exiting...\n", sig)
diff --git a/common/service.go b/common/service.go
index 2d86baafe..8d4de30a8 100644
--- a/common/service.go
+++ b/common/service.go
@@ -140,7 +140,7 @@ func (bs *BaseService) OnStop() {}
 
 // Implements Service
 func (bs *BaseService) Reset() (bool, error) {
-	if stopped := atomic.CompareAndSwapUint32(&bs.stopped, 1, 0); !stopped {
+	if !atomic.CompareAndSwapUint32(&bs.stopped, 1, 0) {
 		bs.Logger.Debug(Fmt("Can't reset %v. Not stopped", bs.name), "impl", bs.impl)
 		return false, nil
 	}

From 35e38e8932e69dcf3038729c611358f9c2ac960d Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Wed, 11 Oct 2017 12:42:54 +0400
Subject: [PATCH 09/26] call go env GOPATH if env var is not found (Refs #60)

---
 common/os.go      | 16 +++++++++++++++-
 common/os_test.go | 23 +++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/common/os.go b/common/os.go
index e0a009264..8af6cd22e 100644
--- a/common/os.go
+++ b/common/os.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"os/exec"
 	"os/signal"
 	"path/filepath"
 	"strings"
@@ -13,9 +14,22 @@ import (
 )
 
 var (
-	GoPath = os.Getenv("GOPATH")
+	GoPath = gopath()
 )
 
+func gopath() string {
+	path := os.Getenv("GOPATH")
+	if len(path) == 0 {
+		goCmd := exec.Command("go", "env", "GOPATH")
+		out, err := goCmd.Output()
+		if err != nil {
+			panic(fmt.Sprintf("failed to determine gopath: %v", err))
+		}
+		path = string(out)
+	}
+	return path
+}
+
 func TrapSignal(cb func()) {
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
diff --git a/common/os_test.go b/common/os_test.go
index 05359e36e..168eb438c 100644
--- a/common/os_test.go
+++ b/common/os_test.go
@@ -27,3 +27,26 @@ func TestWriteFileAtomic(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestGoPath(t *testing.T) {
+	// restore original gopath upon exit
+	path := os.Getenv("GOPATH")
+	defer func() {
+		_ = os.Setenv("GOPATH", path)
+	}()
+
+	err := os.Setenv("GOPATH", "~/testgopath")
+	if err != nil {
+		t.Fatal(err)
+	}
+	path = gopath()
+	if path != "~/testgopath" {
+		t.Fatalf("gopath should return GOPATH env var if set, got %v", path)
+	}
+	os.Unsetenv("GOPATH")
+
+	path = gopath()
+	if path == "~/testgopath" || path == "" {
+		t.Fatalf("gopath should return go env GOPATH result if env var does not exist, got %v", path)
+	}
+}

From 7166252a521951eb8b6bd26db28b2b90586941a9 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Wed, 11 Oct 2017 12:48:05 +0400
Subject: [PATCH 10/26] add codeowners file [ci skip]

---
 CODEOWNERS | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 CODEOWNERS

diff --git a/CODEOWNERS b/CODEOWNERS
new file mode 100644
index 000000000..d2dddf85a
--- /dev/null
+++ b/CODEOWNERS
@@ -0,0 +1,3 @@
+*       @melekes @ebuchman
+*.md    @zramsay
+*.rst   @zramsay

From 6b1e3bcee3cf69fbac004cef8f8f3788f12cd58e Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@cloudhead.io>
Date: Fri, 13 Oct 2017 13:03:43 +0200
Subject: [PATCH 11/26] Add comments about copying

---
 db/go_level_db.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/db/go_level_db.go b/db/go_level_db.go
index 2d2ba44e3..f3ed79e30 100644
--- a/db/go_level_db.go
+++ b/db/go_level_db.go
@@ -121,6 +121,7 @@ type goLevelDBIterator struct {
 	iterator.Iterator
 }
 
+// Key returns a copy of the current key.
 func (it *goLevelDBIterator) Key() []byte {
 	key := it.Key()
 	k := make([]byte, len(key))
@@ -129,6 +130,7 @@ func (it *goLevelDBIterator) Key() []byte {
 	return k
 }
 
+// Value returns a copy of the current value.
 func (it *goLevelDBIterator) Value() []byte {
 	val := it.Value()
 	v := make([]byte, len(val))

From 0b22b27bbb08947e3875dcfe22f95b983635eb0a Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Mon, 16 Oct 2017 22:38:37 +0400
Subject: [PATCH 12/26] avoid infinite recursion by proxying to iterator

```
WARNING: staticcheck, gosimple and unused are all set, using megacheck instead
db/go_level_db.go:126:15:warning: infinite recursive call (SA5007) (megacheck)
db/go_level_db.go:135:17:warning: infinite recursive call (SA5007) (megacheck)
db/mem_db.go:106:2:warning: redundant return statement (S1023) (megacheck)
```

https://circleci.com/gh/tendermint/tmlibs/220

Also remove unnecessary return statement
---
 db/go_level_db.go | 18 +++++++++++++++---
 db/mem_db.go      |  1 -
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/db/go_level_db.go b/db/go_level_db.go
index f3ed79e30..4abd76112 100644
--- a/db/go_level_db.go
+++ b/db/go_level_db.go
@@ -118,12 +118,12 @@ func (db *GoLevelDB) Stats() map[string]string {
 }
 
 type goLevelDBIterator struct {
-	iterator.Iterator
+	source iterator.Iterator
 }
 
 // Key returns a copy of the current key.
 func (it *goLevelDBIterator) Key() []byte {
-	key := it.Key()
+	key := it.source.Key()
 	k := make([]byte, len(key))
 	copy(k, key)
 
@@ -132,13 +132,25 @@ func (it *goLevelDBIterator) Key() []byte {
 
 // Value returns a copy of the current value.
 func (it *goLevelDBIterator) Value() []byte {
-	val := it.Value()
+	val := it.source.Value()
 	v := make([]byte, len(val))
 	copy(v, val)
 
 	return v
 }
 
+func (it *goLevelDBIterator) Error() error {
+	return it.source.Error()
+}
+
+func (it *goLevelDBIterator) Next() bool {
+	return it.source.Next()
+}
+
+func (it *goLevelDBIterator) Release() {
+	it.source.Release()
+}
+
 func (db *GoLevelDB) Iterator() Iterator {
 	return &goLevelDBIterator{db.db.NewIterator(nil, nil)}
 }
diff --git a/db/mem_db.go b/db/mem_db.go
index 55d594fa6..077427509 100644
--- a/db/mem_db.go
+++ b/db/mem_db.go
@@ -103,7 +103,6 @@ func (it *memDBIterator) Value() []byte {
 func (it *memDBIterator) Release() {
 	it.db = nil
 	it.keys = nil
-	return
 }
 
 func (it *memDBIterator) Error() error {

From 498fb1134a550761f2cc0acef5cf9fbc76fb2562 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Tue, 17 Oct 2017 16:26:52 +0400
Subject: [PATCH 13/26] write docs for autofile/group

---
 autofile/group.go | 73 +++++++++++++++++++++++++++++------------------
 1 file changed, 46 insertions(+), 27 deletions(-)

diff --git a/autofile/group.go b/autofile/group.go
index eedb67b50..b66b5c692 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -18,6 +18,13 @@ import (
 	. "github.com/tendermint/tmlibs/common"
 )
 
+const (
+	groupCheckDuration    = 5000 * time.Millisecond
+	defaultHeadSizeLimit  = 10 * 1024 * 1024       // 10MB
+	defaultTotalSizeLimit = 1 * 1024 * 1024 * 1024 // 1GB
+	maxFilesToRemove      = 4                      // needs to be greater than 1
+)
+
 /*
 You can open a Group to keep restrictions on an AutoFile, like
 the maximum size of each chunk, and/or the total amount of bytes
@@ -25,33 +32,27 @@ stored in the group.
 
 The first file to be written in the Group.Dir is the head file.
 
-  Dir/
-  - <HeadPath>
+	Dir/
+	- <HeadPath>
 
 Once the Head file reaches the size limit, it will be rotated.
 
-  Dir/
-  - <HeadPath>.000   // First rolled file
-  - <HeadPath>       // New head path, starts empty.
-                     // The implicit index is 001.
+	Dir/
+	- <HeadPath>.000   // First rolled file
+	- <HeadPath>       // New head path, starts empty.
+										 // The implicit index is 001.
 
 As more files are written, the index numbers grow...
 
-  Dir/
-  - <HeadPath>.000   // First rolled file
-  - <HeadPath>.001   // Second rolled file
-  - ...
-  - <HeadPath>       // New head path
+	Dir/
+	- <HeadPath>.000   // First rolled file
+	- <HeadPath>.001   // Second rolled file
+	- ...
+	- <HeadPath>       // New head path
 
 The Group can also be used to binary-search for some line,
 assuming that marker lines are written occasionally.
 */
-
-const groupCheckDuration = 5000 * time.Millisecond
-const defaultHeadSizeLimit = 10 * 1024 * 1024        // 10MB
-const defaultTotalSizeLimit = 1 * 1024 * 1024 * 1024 // 1GB
-const maxFilesToRemove = 4                           // needs to be greater than 1
-
 type Group struct {
 	BaseService
 
@@ -109,37 +110,43 @@ func (g *Group) OnStop() {
 	g.ticker.Stop()
 }
 
+// SetHeadSizeLimit allows you to overwrite default head size limit - 10MB.
 func (g *Group) SetHeadSizeLimit(limit int64) {
 	g.mtx.Lock()
 	g.headSizeLimit = limit
 	g.mtx.Unlock()
 }
 
+// HeadSizeLimit returns the current head size limit.
 func (g *Group) HeadSizeLimit() int64 {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
 	return g.headSizeLimit
 }
 
+// SetTotalSizeLimit allows you to overwrite default total size limit of the
+// group - 1GB.
 func (g *Group) SetTotalSizeLimit(limit int64) {
 	g.mtx.Lock()
 	g.totalSizeLimit = limit
 	g.mtx.Unlock()
 }
 
+// TotalSizeLimit returns total size limit of the group.
 func (g *Group) TotalSizeLimit() int64 {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
 	return g.totalSizeLimit
 }
 
+// MaxIndex returns index of the last file in the group.
 func (g *Group) MaxIndex() int {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
 	return g.maxIndex
 }
 
-// Auto appends "\n"
+// WriteLine writes line into the current head of the group. It also appends "\n".
 // NOTE: Writes are buffered so they don't write synchronously
 // TODO: Make it halt if space is unavailable
 func (g *Group) WriteLine(line string) error {
@@ -149,6 +156,8 @@ func (g *Group) WriteLine(line string) error {
 	return err
 }
 
+// Flush writes any buffered data to the underlying file and commits the
+// current content of the file to stable storage.
 func (g *Group) Flush() error {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
@@ -223,6 +232,8 @@ func (g *Group) checkTotalSizeLimit() {
 	}
 }
 
+// RotateFile causes group to close the current head and assign it some index.
+// Note it does not create a new head.
 func (g *Group) RotateFile() {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
@@ -241,8 +252,8 @@ func (g *Group) RotateFile() {
 	g.maxIndex += 1
 }
 
-// NOTE: if error, returns no GroupReader.
-// CONTRACT: Caller must close the returned GroupReader
+// NewReader returns a new group reader.
+// CONTRACT: Caller must close the returned GroupReader.
 func (g *Group) NewReader(index int) (*GroupReader, error) {
 	r := newGroupReader(g)
 	err := r.SetIndex(index)
@@ -423,14 +434,15 @@ GROUP_LOOP:
 	return
 }
 
+// GroupInfo holds information about the group.
 type GroupInfo struct {
-	MinIndex  int
-	MaxIndex  int
-	TotalSize int64
-	HeadSize  int64
+	MinIndex  int   // index of the first file in the group, including head
+	MaxIndex  int   // index of the last file in the group, including head
+	TotalSize int64 // total size of the group
+	HeadSize  int64 // size of the head
 }
 
-// Returns info after scanning all files in g.Head's dir
+// Returns info after scanning all files in g.Head's dir.
 func (g *Group) ReadGroupInfo() GroupInfo {
 	g.mtx.Lock()
 	defer g.mtx.Unlock()
@@ -505,6 +517,7 @@ func filePathForIndex(headPath string, index int, maxIndex int) string {
 
 //--------------------------------------------------------------------------------
 
+// GroupReader provides an interface for reading from a Group.
 type GroupReader struct {
 	*Group
 	mtx       sync.Mutex
@@ -524,6 +537,7 @@ func newGroupReader(g *Group) *GroupReader {
 	}
 }
 
+// Close closes the GroupReader by closing the cursor file.
 func (gr *GroupReader) Close() error {
 	gr.mtx.Lock()
 	defer gr.mtx.Unlock()
@@ -540,7 +554,7 @@ func (gr *GroupReader) Close() error {
 	}
 }
 
-// Reads a line (without delimiter)
+// ReadLine reads a line (without delimiter).
 // just return io.EOF if no new lines found.
 func (gr *GroupReader) ReadLine() (string, error) {
 	gr.mtx.Lock()
@@ -613,6 +627,9 @@ func (gr *GroupReader) openFile(index int) error {
 	return nil
 }
 
+// PushLine makes the given line the current one, so the next time somebody
+// calls ReadLine, this line will be returned.
+// panics if called twice without calling ReadLine.
 func (gr *GroupReader) PushLine(line string) {
 	gr.mtx.Lock()
 	defer gr.mtx.Unlock()
@@ -624,13 +641,15 @@ func (gr *GroupReader) PushLine(line string) {
 	}
 }
 
-// Cursor's file index.
+// CurIndex returns cursor's file index.
 func (gr *GroupReader) CurIndex() int {
 	gr.mtx.Lock()
 	defer gr.mtx.Unlock()
 	return gr.curIndex
 }
 
+// SetIndex sets the cursor's file index to index by opening a file at this
+// position.
 func (gr *GroupReader) SetIndex(index int) error {
 	gr.mtx.Lock()
 	defer gr.mtx.Unlock()

From 45095e83e790624980240e83628d6971cafa5495 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Tue, 17 Oct 2017 16:48:44 +0400
Subject: [PATCH 14/26] add Write method to autofile/Group

---
 autofile/group.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/autofile/group.go b/autofile/group.go
index b66b5c692..947c295f8 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -146,6 +146,17 @@ func (g *Group) MaxIndex() int {
 	return g.maxIndex
 }
 
+// Write writes the contents of p into the current head of the group. It
+// returns the number of bytes written. If nn < len(p), it also returns an
+// error explaining why the write is short.
+// NOTE: Writes are buffered so they don't write synchronously
+// TODO: Make it halt if space is unavailable
+func (g *Group) Write(p []byte) (nn int, err error) {
+	g.mtx.Lock()
+	defer g.mtx.Unlock()
+	return g.headBuf.Write(p)
+}
+
 // WriteLine writes line into the current head of the group. It also appends "\n".
 // NOTE: Writes are buffered so they don't write synchronously
 // TODO: Make it halt if space is unavailable

From aace56018a5f70c09a2ab26b280c943a85aba5d7 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Fri, 20 Oct 2017 12:38:45 +0400
Subject: [PATCH 15/26] add Read method to GroupReader

---
 autofile/group.go | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/autofile/group.go b/autofile/group.go
index 947c295f8..2c6aa6109 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -565,6 +565,42 @@ func (gr *GroupReader) Close() error {
 	}
 }
 
+// Read implements io.Reader, reading bytes from the current Reader
+// incrementing index until enough bytes are read.
+func (gr *GroupReader) Read(p []byte) (n int, err error) {
+	gr.mtx.Lock()
+	defer gr.mtx.Unlock()
+
+	// Open file if not open yet
+	if gr.curReader == nil {
+		if err = gr.openFile(gr.curIndex); err != nil {
+			return 0, err
+		}
+	}
+
+	// Iterate over files until enough bytes are read
+	lenP := len(p)
+	for {
+		nn, err := gr.curReader.Read(p[n:])
+		n += nn
+		if err == io.EOF {
+			// Open the next file
+			if err1 := gr.openFile(gr.curIndex + 1); err1 != nil {
+				return n, err1
+			}
+			if n >= lenP {
+				return n, nil
+			} else {
+				continue
+			}
+		} else if err != nil {
+			return n, err
+		}
+	}
+
+	return n, err
+}
+
 // ReadLine reads a line (without delimiter).
 // just return io.EOF if no new lines found.
 func (gr *GroupReader) ReadLine() (string, error) {

From 35e81018e9bd183be7121b6b900dff3d49e234d5 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Fri, 20 Oct 2017 13:09:11 +0400
Subject: [PATCH 16/26] add MinIndex method to Group

---
 autofile/group.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/autofile/group.go b/autofile/group.go
index 2c6aa6109..d5797d087 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -146,6 +146,13 @@ func (g *Group) MaxIndex() int {
 	return g.maxIndex
 }
 
+// MinIndex returns index of the first file in the group.
+func (g *Group) MinIndex() int {
+	g.mtx.Lock()
+	defer g.mtx.Unlock()
+	return g.minIndex
+}
+
 // Write writes the contents of p into the current head of the group. It
 // returns the number of bytes written. If nn < len(p), it also returns an
 // error explaining why the write is short.

From c75ddd0fa3f669c1b391291a10361ddf8c5170bf Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Mon, 23 Oct 2017 13:02:02 +0400
Subject: [PATCH 17/26] return err if empty slice given

---
 autofile/group.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/autofile/group.go b/autofile/group.go
index d5797d087..4b3cd6565 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -575,6 +575,11 @@ func (gr *GroupReader) Close() error {
 // Read implements io.Reader, reading bytes from the current Reader
 // incrementing index until enough bytes are read.
 func (gr *GroupReader) Read(p []byte) (n int, err error) {
+	lenP := len(p)
+	if lenP == 0 {
+		return 0, errors.New("given empty slice")
+	}
+
 	gr.mtx.Lock()
 	defer gr.mtx.Unlock()
 
@@ -586,7 +591,6 @@ func (gr *GroupReader) Read(p []byte) (n int, err error) {
 	}
 
 	// Iterate over files until enough bytes are read
-	lenP := len(p)
 	for {
 		nn, err := gr.curReader.Read(p[n:])
 		n += nn

From 21b2c26fb1b26edf5846792890e01eaa8a472508 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Mon, 23 Oct 2017 13:02:14 +0400
Subject: [PATCH 18/26] GroupReader#Read: return io.EOF if file is empty

---
 autofile/group.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/autofile/group.go b/autofile/group.go
index 4b3cd6565..6d70a3dbb 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -606,6 +606,8 @@ func (gr *GroupReader) Read(p []byte) (n int, err error) {
 			}
 		} else if err != nil {
 			return n, err
+		} else if nn == 0 { // empty file
+			return n, err
 		}
 	}
 

From 0eff425bc7e3d6137ea3c59ad7436eafe5ef55d2 Mon Sep 17 00:00:00 2001
From: Silas Davis <silas@monax.io>
Date: Mon, 23 Oct 2017 18:51:49 +0100
Subject: [PATCH 19/26] fix zeroed buffer getting flushed to the empty event

---
 events/event_cache.go      | 12 ++++--------
 events/event_cache_test.go | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 8 deletions(-)
 create mode 100644 events/event_cache_test.go

diff --git a/events/event_cache.go b/events/event_cache.go
index 905f1096a..f508e873d 100644
--- a/events/event_cache.go
+++ b/events/event_cache.go
@@ -1,9 +1,5 @@
 package events
 
-const (
-	eventsBufferSize = 1000
-)
-
 // An EventCache buffers events for a Fireable
 // All events are cached. Filtering happens on Flush
 type EventCache struct {
@@ -14,8 +10,7 @@ type EventCache struct {
 // Create a new EventCache with an EventSwitch as backend
 func NewEventCache(evsw Fireable) *EventCache {
 	return &EventCache{
-		evsw:   evsw,
-		events: make([]eventInfo, eventsBufferSize),
+		evsw: evsw,
 	}
 }
 
@@ -27,7 +22,7 @@ type eventInfo struct {
 
 // Cache an event to be fired upon finality.
 func (evc *EventCache) FireEvent(event string, data EventData) {
-	// append to list
+	// append to list (go will grow our backing array exponentially)
 	evc.events = append(evc.events, eventInfo{event, data})
 }
 
@@ -37,5 +32,6 @@ func (evc *EventCache) Flush() {
 	for _, ei := range evc.events {
 		evc.evsw.FireEvent(ei.event, ei.data)
 	}
-	evc.events = make([]eventInfo, eventsBufferSize)
+	// Clear the buffer, since we only add to it with append it's safe to just set it to nil and maybe safe an allocation
+	evc.events = nil
 }
diff --git a/events/event_cache_test.go b/events/event_cache_test.go
new file mode 100644
index 000000000..ab321da3a
--- /dev/null
+++ b/events/event_cache_test.go
@@ -0,0 +1,35 @@
+package events
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEventCache_Flush(t *testing.T) {
+	evsw := NewEventSwitch()
+	evsw.Start()
+	evsw.AddListenerForEvent("nothingness", "", func(data EventData) {
+		// Check we are not initialising an empty buffer full of zeroed eventInfos in the EventCache
+		require.FailNow(t, "We should never receive a message on this switch since none are fired")
+	})
+	evc := NewEventCache(evsw)
+	evc.Flush()
+	// Check after reset
+	evc.Flush()
+	fail := true
+	pass := false
+	evsw.AddListenerForEvent("somethingness", "something", func(data EventData) {
+		if fail {
+			require.FailNow(t, "Shouldn't see a message until flushed")
+		}
+		pass = true
+	})
+	evc.FireEvent("something", struct{ int }{1})
+	evc.FireEvent("something", struct{ int }{2})
+	evc.FireEvent("something", struct{ int }{3})
+	fail = false
+	evc.Flush()
+	assert.True(t, pass)
+}

From 81591e288e87eba7735df53207f74a09ba5f289a Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Tue, 24 Oct 2017 23:19:53 +0400
Subject: [PATCH 20/26] fix metalinter warnings

---
 autofile/group.go | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/autofile/group.go b/autofile/group.go
index 6d70a3dbb..bbf77d27e 100644
--- a/autofile/group.go
+++ b/autofile/group.go
@@ -591,8 +591,9 @@ func (gr *GroupReader) Read(p []byte) (n int, err error) {
 	}
 
 	// Iterate over files until enough bytes are read
+	var nn int
 	for {
-		nn, err := gr.curReader.Read(p[n:])
+		nn, err = gr.curReader.Read(p[n:])
 		n += nn
 		if err == io.EOF {
 			// Open the next file
@@ -610,8 +611,6 @@ func (gr *GroupReader) Read(p []byte) (n int, err error) {
 			return n, err
 		}
 	}
-
-	return n, err
 }
 
 // ReadLine reads a line (without delimiter).

From 103fee61921ee8bebd055bedd0815ddc71e03d90 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Tue, 24 Oct 2017 23:20:17 +0400
Subject: [PATCH 21/26] add tests for autofile group Write, reader#Read

---
 autofile/group_test.go | 91 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/autofile/group_test.go b/autofile/group_test.go
index 0cfcef72f..398ea3ae9 100644
--- a/autofile/group_test.go
+++ b/autofile/group_test.go
@@ -1,6 +1,7 @@
 package autofile
 
 import (
+	"bytes"
 	"errors"
 	"io"
 	"io/ioutil"
@@ -400,3 +401,93 @@ func TestFindLast4(t *testing.T) {
 	// Cleanup
 	destroyTestGroup(t, g)
 }
+
+func TestWrite(t *testing.T) {
+	g := createTestGroup(t, 0)
+
+	written := []byte("Medusa")
+	g.Write(written)
+	g.Flush()
+
+	read := make([]byte, len(written))
+	gr, err := g.NewReader(0)
+	if err != nil {
+		t.Fatalf("Failed to create reader: %v", err)
+	}
+	_, err = gr.Read(read)
+	if err != nil {
+		t.Fatalf("Failed to read data: %v", err)
+	}
+
+	if !bytes.Equal(written, read) {
+		t.Errorf("%s, %s should be equal", string(written), string(read))
+	}
+
+	// Cleanup
+	destroyTestGroup(t, g)
+}
+
+func TestGroupReaderRead(t *testing.T) {
+	g := createTestGroup(t, 0)
+
+	professor := []byte("Professor Monster")
+	g.Write(professor)
+	g.Flush()
+	g.RotateFile()
+	frankenstein := []byte("Frankenstein's Monster")
+	g.Write(frankenstein)
+	g.Flush()
+
+	totalWrittenLength := len(professor) + len(frankenstein)
+	read := make([]byte, totalWrittenLength)
+	gr, err := g.NewReader(0)
+	if err != nil {
+		t.Fatalf("Failed to create reader: %v", err)
+	}
+	n, err := gr.Read(read)
+	if err != nil {
+		t.Fatalf("Failed to read data: %v", err)
+	}
+	if n != totalWrittenLength {
+		t.Errorf("Failed to read enough bytes: wanted %d, but read %d", totalWrittenLength, n)
+	}
+
+	professorPlusFrankenstein := professor
+	professorPlusFrankenstein = append(professorPlusFrankenstein, frankenstein...)
+	if !bytes.Equal(read, professorPlusFrankenstein) {
+		t.Errorf("%s, %s should be equal", string(professorPlusFrankenstein), string(read))
+	}
+
+	// Cleanup
+	destroyTestGroup(t, g)
+}
+
+func TestMinIndex(t *testing.T) {
+	g := createTestGroup(t, 0)
+
+	if g.MinIndex() != 0 {
+		t.Error("MinIndex should be zero at the beginning")
+	}
+
+	// Cleanup
+	destroyTestGroup(t, g)
+}
+
+func TestMaxIndex(t *testing.T) {
+	g := createTestGroup(t, 0)
+
+	if g.MaxIndex() != 0 {
+		t.Error("MaxIndex should be zero at the beginning")
+	}
+
+	g.WriteLine("Line 1")
+	g.Flush()
+	g.RotateFile()
+
+	if g.MaxIndex() != 1 {
+		t.Error("MaxIndex should point to the last file")
+	}
+
+	// Cleanup
+	destroyTestGroup(t, g)
+}

From f99c73502ca32782c0e68258848cc5c365e133b6 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Tue, 24 Oct 2017 23:30:05 +0400
Subject: [PATCH 22/26] add codecov

---
 circle.yml | 10 +++++-----
 test.sh    | 12 ++++++++++++
 2 files changed, 17 insertions(+), 5 deletions(-)
 create mode 100755 test.sh

diff --git a/circle.yml b/circle.yml
index 8e3ad168b..3dba976be 100644
--- a/circle.yml
+++ b/circle.yml
@@ -1,11 +1,9 @@
 machine:
   environment:
-    GOPATH: /home/ubuntu/.go_workspace
+    GOPATH: "${HOME}/.go_workspace"
     PROJECT_PARENT_PATH: "$GOPATH/src/github.com/$CIRCLE_PROJECT_USERNAME"
     PROJECT_PATH: $GOPATH/src/github.com/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME
-    GO15VENDOREXPERIMENT: 1
   hosts:
-    circlehost: 127.0.0.1
     localhost: 127.0.0.1
 
 dependencies:
@@ -17,5 +15,7 @@ dependencies:
 
 test:
   override:
-    - "go version"
-    - "cd $PROJECT_PATH && make get_vendor_deps && make metalinter_test && make test"
+    - cd $PROJECT_PATH && make get_vendor_deps && make metalinter_test && bash ./test.sh
+  post:
+    - cd "$PROJECT_PATH" && bash <(curl -s https://codecov.io/bash) -f coverage.txt
+    - cd "$PROJECT_PATH" && mv coverage.txt "${CIRCLE_ARTIFACTS}"
diff --git a/test.sh b/test.sh
new file mode 100755
index 000000000..012162b07
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -e
+echo "" > coverage.txt
+
+for d in $(go list ./... | grep -v vendor); do
+    go test -race -coverprofile=profile.out -covermode=atomic "$d"
+    if [ -f profile.out ]; then
+        cat profile.out >> coverage.txt
+        rm profile.out
+    fi
+done

From bcf15e527d89444bf260fd83699ef70fde2fb6e1 Mon Sep 17 00:00:00 2001
From: Anton Kaliaev <anton.kalyaev@gmail.com>
Date: Wed, 25 Oct 2017 11:01:52 +0400
Subject: [PATCH 23/26] make GoPath a function

otherwise it could try to execute go binary and panic if no go binary
found. See https://github.com/tendermint/tendermint/issues/782
---
 common/os.go      | 13 +++++++++----
 common/os_test.go | 27 ++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/common/os.go b/common/os.go
index 8af6cd22e..6b591ce59 100644
--- a/common/os.go
+++ b/common/os.go
@@ -13,11 +13,15 @@ import (
 	"syscall"
 )
 
-var (
-	GoPath = gopath()
-)
+var gopath string
+
+// GoPath returns GOPATH env variable value. If it is not set, this function
+// will try to call `go env GOPATH` subcommand.
+func GoPath() string {
+	if gopath != "" {
+		return gopath
+	}
 
-func gopath() string {
 	path := os.Getenv("GOPATH")
 	if len(path) == 0 {
 		goCmd := exec.Command("go", "env", "GOPATH")
@@ -27,6 +31,7 @@ func gopath() string {
 		}
 		path = string(out)
 	}
+	gopath = path
 	return path
 }
 
diff --git a/common/os_test.go b/common/os_test.go
index 168eb438c..126723aa6 100644
--- a/common/os_test.go
+++ b/common/os_test.go
@@ -39,14 +39,31 @@ func TestGoPath(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	path = gopath()
+	path = GoPath()
 	if path != "~/testgopath" {
-		t.Fatalf("gopath should return GOPATH env var if set, got %v", path)
+		t.Fatalf("should get GOPATH env var value, got %v", path)
 	}
 	os.Unsetenv("GOPATH")
 
-	path = gopath()
-	if path == "~/testgopath" || path == "" {
-		t.Fatalf("gopath should return go env GOPATH result if env var does not exist, got %v", path)
+	path = GoPath()
+	if path != "~/testgopath" {
+		t.Fatalf("subsequent calls should return the same value, got %v", path)
+	}
+}
+
+func TestGoPathWithoutEnvVar(t *testing.T) {
+	// restore original gopath upon exit
+	path := os.Getenv("GOPATH")
+	defer func() {
+		_ = os.Setenv("GOPATH", path)
+	}()
+
+	os.Unsetenv("GOPATH")
+	// reset cache
+	gopath = ""
+
+	path = GoPath()
+	if path == "" || path == "~/testgopath" {
+		t.Fatalf("should get nonempty result of calling go env GOPATH, got %v", path)
 	}
 }

From 42145a82bd953e4a666bcc01a37e2d140b9c1e8e Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Thu, 26 Oct 2017 20:57:33 -0400
Subject: [PATCH 24/26] version and changelog

---
 CHANGELOG.md       | 15 +++++++++++++++
 version/version.go |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e36a02d9a..3a21dd5dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,20 @@
 # Changelog
 
+## 0.4.0 (October 26, 2017)
+
+BREAKING:
+ - [common] GoPath is now a function
+ - [db] `DB` and `Iterator` interfaces have new methods to better support iteration
+
+FEATURES:
+ - [autofile] `Read([]byte)` and `Write([]byte)` methods on `Group` to support binary WAL
+
+IMPROVEMENTS:
+ - comments and linting
+
+BUG FIXES:
+ - [events] fix allocation error prefixing cache with 1000 empty events
+
 ## 0.3.2 (October 2, 2017)
 
 BUG FIXES:
diff --git a/version/version.go b/version/version.go
index 77580b5ad..c1635d202 100644
--- a/version/version.go
+++ b/version/version.go
@@ -1,3 +1,3 @@
 package version
 
-const Version = "0.3.2"
+const Version = "0.4.0"

From 092eb701c7276907cdbed258750e22ce895b6735 Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Fri, 27 Oct 2017 11:01:40 -0400
Subject: [PATCH 25/26] cmn: Kill

---
 common/os.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/common/os.go b/common/os.go
index 6b591ce59..81f703c7d 100644
--- a/common/os.go
+++ b/common/os.go
@@ -50,6 +50,12 @@ func TrapSignal(cb func()) {
 	select {}
 }
 
+// Kill the running process by sending itself SIGTERM
+func Kill() error {
+	pid := os.Getpid()
+	return syscall.Kill(pid, syscall.SIGTERM)
+}
+
 func Exit(s string) {
 	fmt.Printf(s + "\n")
 	os.Exit(1)

From b14c99669810fdb9bdd305fe0e09f72c86df815b Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Fri, 27 Oct 2017 11:52:10 -0400
Subject: [PATCH 26/26] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a21dd5dd..c380fdcd0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ BREAKING:
 
 FEATURES:
  - [autofile] `Read([]byte)` and `Write([]byte)` methods on `Group` to support binary WAL
+ - [common] `Kill()` sends SIGTERM to the current process
 
 IMPROVEMENTS:
  - comments and linting