refactor: speed up isAllowedErrAndFunc via map

Author: psydvl

errorlint/allowed.go

@@ -77,6 +77,17 @@ var allowedErrors = []struct {
 	{err: "context.Canceled", fun: "(context.Context).Err"},
 }
 
+var allowedErrorsMap = make(map[string]map[string]struct{})
+
+func init() {
+	for _, pair := range allowedErrors {
+		if _, ok := allowedErrorsMap[pair.err]; !ok {
+			allowedErrorsMap[pair.err] = make(map[string]struct{})
+		}
+		allowedErrorsMap[pair.err][pair.fun] = struct{}{}
+	}
+}
+
 var allowedErrorWildcards = []struct {
 	err string
 	fun string
@@ -86,17 +97,18 @@ var allowedErrorWildcards = []struct {
 }
 
 func isAllowedErrAndFunc(err, fun string) bool {
-	for _, allow := range allowedErrorWildcards {
-		if strings.HasPrefix(fun, allow.fun) && strings.HasPrefix(err, allow.err) {
+	if allowedFuncs, allowErr := allowedErrorsMap[err]; allowErr {
+		if _, allow := allowedFuncs[fun]; allow {
 			return true
 		}
 	}
 
-	for _, allow := range allowedErrors {
-		if allow.fun == fun && allow.err == err {
+	for _, allow := range allowedErrorWildcards {
+		if strings.HasPrefix(fun, allow.fun) && strings.HasPrefix(err, allow.err) {
 			return true
 		}
 	}
+
 	return false
 }
 

errorlint/allowed_test.go

@@ -0,0 +1,42 @@
+package errorlint
+
+import (
+	"testing"
+)
+
+func Test_isAllowedErrAndFunc(t *testing.T) {
+	testCases := []struct {
+		desc   string
+		fun    string
+		err    string
+		expect bool
+	}{
+		{
+			desc:   "allowedErrors: (io.Reader).Read",
+			err:    "io.EOF",
+			fun:    "(io.Reader).Read",
+			expect: true,
+		},
+		{
+			desc:   "allowedErrorWildcards: golang.org/x/sys/unix.",
+			err:    "golang.org/x/sys/unix.EINVAL",
+			fun:    "golang.org/x/sys/unix.EpollCreate",
+			expect: true,
+		},
+		{
+			desc:   "errorlint.Reader Read",
+			err:    "io.EOF",
+			fun:    "(errorlint.Reader).Read",
+			expect: false,
+		},
+		// {desc: "fail test", expect: true},
+	}
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			result := isAllowedErrAndFunc(tt.err, tt.fun)
+			if tt.expect != result {
+				t.Errorf("Not equal:\n\texpect: %t,\n\tactual: %t\n", tt.expect, result)
+			}
+		})
+	}
+}