CI: Fix golangci-lint linter issues, add prealloc linter and bump version depends for Go 1.18 (#915)

* Bump CI versions

* Specifically set go version as 1.17.x bumps it to 1.18

* Another

* Adjust AppVeyor

* Part 1 of linter issues

* Part 2

* Fix various linters and improvements

* Part 3

* Finishing touches

* Tests and EqualFold

* Fix nitterinos plus bonus requester jobs bump for exchanges with large number of tests

* Fix nitterinos and bump golangci-lint timeout for AppVeyor

* Address nits, ensure all books are returned on err due to syncer regression

* Fix the wiggins

* Fix duplication

* Fix nitterinos

common/cache/cache_test.go

@@ -2,6 +2,8 @@ package cache
 
 import (
 	"testing"
+
+	"github.com/thrasher-corp/gocryptotrader/common/convert"
 )
 
 func TestCache(t *testing.T) {
@@ -16,12 +18,11 @@ func TestCache(t *testing.T) {
 	if v == nil {
 		t.Fatal("expected cache to contain \"hello\" key")
 	}
-	if v.(string) != "world" {
+	if convert.InterfaceToStringOrZeroValue(v) != "world" {
 		t.Fatal("expected \"hello\" key to contain value \"world\"")
 	}
 
-	r := lruCache.Remove("hello")
-	if !r {
+	if r := lruCache.Remove("hello"); !r {
 		t.Fatal("expected \"hello\" key to be removed from cache")
 	}
 
@@ -77,39 +78,39 @@ func TestAdd(t *testing.T) {
 	if v == nil {
 		t.Fatal("expected cache to contain \"2\" key")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected \"2\" key to contain value \"2\"")
 	}
 	k, v := lruCache.getNewest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected latest key to be 2")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected latest value to be 2")
 	}
 	lruCache.Add(3, 3)
 	k, _ = lruCache.getNewest()
-	if k.(int) != 3 {
+	if convert.InterfaceToIntOrZeroValue(k) != 3 {
 		t.Fatal("expected latest key to be 3")
 	}
 	k, _ = lruCache.getOldest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected oldest key to be 2")
 	}
 	k, v = lruCache.getOldest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected oldest key to be 2")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected latest value to be 2")
 	}
 	lruCache.Add(2, 2)
 	k, _ = lruCache.getNewest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected latest key to be 2")
 	}
 	k, _ = lruCache.getOldest()
-	if k.(int) != 3 {
+	if convert.InterfaceToIntOrZeroValue(k) != 3 {
 		t.Fatal("expected oldest key to be 3")
 	}
 }

common/cache/lru.go

@@ -24,7 +24,9 @@ func NewLRUCache(capacity uint64) *LRU {
 func (l *LRU) Add(key, value interface{}) {
 	if f, o := l.items[key]; o {
 		l.l.MoveToFront(f)
-		f.Value.(*item).value = value
+		if v, ok := f.Value.(*item); ok {
+			v.value = value
+		}
 		return
 	}
 
@@ -40,7 +42,9 @@ func (l *LRU) Add(key, value interface{}) {
 func (l *LRU) Get(key interface{}) interface{} {
 	if i, f := l.items[key]; f {
 		l.l.MoveToFront(i)
-		return i.Value.(*item).value
+		if v, ok := i.Value.(*item); ok {
+			return v.value
+		}
 	}
 	return nil
 }
@@ -48,7 +52,9 @@ func (l *LRU) Get(key interface{}) interface{} {
 // GetOldest returns the oldest entry
 func (l *LRU) getOldest() (key, value interface{}) {
 	if x := l.l.Back(); x != nil {
-		return x.Value.(*item).key, x.Value.(*item).value
+		if v, ok := x.Value.(*item); ok {
+			return v.key, v.value
+		}
 	}
 	return
 }
@@ -56,7 +62,9 @@ func (l *LRU) getOldest() (key, value interface{}) {
 // GetNewest returns the newest entry
 func (l *LRU) getNewest() (key, value interface{}) {
 	if x := l.l.Front(); x != nil {
-		return x.Value.(*item).key, x.Value.(*item).value
+		if v, ok := x.Value.(*item); ok {
+			return v.key, v.value
+		}
 	}
 	return
 }
@@ -99,5 +107,7 @@ func (l *LRU) removeOldestEntry() {
 // removeElement element from the cache
 func (l *LRU) removeElement(e *list.Element) {
 	l.l.Remove(e)
-	delete(l.items, e.Value.(*item).key)
+	if v, ok := e.Value.(*item); ok {
+		delete(l.items, v.key)
+	}
 }