Update linter config and follow recommendations

.golangci.yml

@@ -4,6 +4,13 @@ linters:
     - wsl
     - gomnd
     - testpackage
+    - wrapcheck
+    - nlreturn
+    - goerr113
+    - exhaustivestruct
+    - exhaustive
+    - cyclop
+    - funlen
 
 issues:
   exclude-rules:
@@ -16,6 +23,9 @@ issues:
         - funlen
         - scopelint
         - gocognit
+        - paralleltest
+        - errorlint
+        - forcetypeassert
     - path: doc\.go
       linters:
         - lll

error_test.go

@@ -13,8 +13,7 @@ func Test_fieldErrors_Error(t *testing.T) {
 
 	got := fe.Error()
 
-	want := "A: aerr, B: berr"
-	if want != got {
+	if want := "A: aerr, B: berr"; want != got {
 		t.Fatalf("want %q, got %q", want, got)
 	}
 

fig.go

@@ -208,7 +208,7 @@ func (f *fig) processField(field *field) error {
 
 	if f.useEnv {
 		if err := f.setFromEnv(field.v, field.path()); err != nil {
-			return fmt.Errorf("unable to set from env: %v", err)
+			return fmt.Errorf("unable to set from env: %w", err)
 		}
 	}
 
@@ -218,7 +218,7 @@ func (f *fig) processField(field *field) error {
 
 	if field.setDefault && isZero(field.v) {
 		if err := f.setDefaultValue(field.v, field.defaultVal); err != nil {
-			return fmt.Errorf("unable to set default: %v", err)
+			return fmt.Errorf("unable to set default: %w", err)
 		}
 	}
 

fig_test.go

@@ -497,8 +497,7 @@ func Test_fig_decodeMap(t *testing.T) {
 		} `fig:"server"`
 	}
 
-	err := fig.decodeMap(m, &cfg)
-	if err != nil {
+	if err := fig.decodeMap(m, &cfg); err != nil {
 		t.Fatalf("unexpected err: %v", err)
 	}
 
@@ -1026,12 +1025,7 @@ func Test_fig_setValue(t *testing.T) {
 			t.Fatalf("unexpected err: %v", err)
 		}
 
-		want, err := regexp.Compile("[a-z]+")
-		if err != nil {
-			t.Fatalf("error parsing time: %v", err)
-		}
-
-		if re.String() != want.String() {
+		if want := regexp.MustCompile("[a-z]+"); re.String() != want.String() {
 			t.Fatalf("want %v, got %v", want, re)
 		}
 	})
@@ -1159,6 +1153,7 @@ func Test_fig_setSlice(t *testing.T) {
 }
 
 func setenv(t *testing.T, key, value string) {
+	t.Helper()
 	if err := os.Setenv(key, value); err != nil {
 		t.Fatalf("os.Setenv() unexpected error: %v", err)
 	}