var-naming: handle possible panic (#1405)

* var-naming: handle possible panic

* Update rule/var_naming.go

Co-authored-by: ccoVeille <3875889+ccoVeille@users.noreply.github.com>

* fix test

* update error message

---------

Co-authored-by: ccoVeille <3875889+ccoVeille@users.noreply.github.com>

Author: alexandear

rule/var_naming.go

@@ -87,11 +87,15 @@ func (r *VarNamingRule) Configure(arguments lint.Arguments) error {
 				if !ok {
 					return fmt.Errorf("invalid third argument to the var-naming rule. Expecting extraBadPackageNames of type slice of strings, but %T", v)
 				}
-				for _, name := range extraBadPackageNames {
+				for i, name := range extraBadPackageNames {
 					if r.extraBadPackageNames == nil {
 						r.extraBadPackageNames = map[string]struct{}{}
 					}
-					r.extraBadPackageNames[strings.ToLower(name.(string))] = struct{}{}
+					n, ok := name.(string)
+					if !ok {
+						return fmt.Errorf("invalid third argument to the var-naming rule: expected element %d of extraBadPackageNames to be a string, but got %v(%T)", i, name, name)
+					}
+					r.extraBadPackageNames[strings.ToLower(n)] = struct{}{}
 				}
 			}
 		}

rule/var_naming_test.go

@@ -117,6 +117,11 @@ func TestVarNamingRule_Configure(t *testing.T) {
 			arguments: lint.Arguments{[]any{""}, []any{""}, []any{map[string]any{"extraBadPackageNames": []int{1}}}},
 			wantErr:   errors.New("invalid third argument to the var-naming rule. Expecting extraBadPackageNames of type slice of strings, but []int"),
 		},
+		{
+			name:      "invalid third argument value type for extraBadPackageNames",
+			arguments: lint.Arguments{[]any{""}, []any{""}, []any{map[string]any{"extraBadPackageNames": []any{"helpers", 5}}}},
+			wantErr:   errors.New("invalid third argument to the var-naming rule: expected element 1 of extraBadPackageNames to be a string, but got 5(int)"),
+		},
 	}
 
 	for _, tt := range tests {