From d9ff6830da56be6f0cd0874685cef759855c63ca Mon Sep 17 00:00:00 2001
From: Gregory Oschwald <goschwald@maxmind.com>
Date: Mon, 11 Nov 2024 09:39:27 -0800
Subject: [PATCH] Don't mix receiver type

---
 client/client.go                           | 2 ++
 internal/geoipupdate/database/reader.go    | 8 ++++++--
 internal/geoipupdate/geoip_updater_test.go | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/client/client.go b/client/client.go
index 3c55397..2ff2561 100644
--- a/client/client.go
+++ b/client/client.go
@@ -10,6 +10,8 @@ import (
 // Client downloads GeoIP2 and GeoLite2 MMDB databases.
 //
 // After creation, it is valid for concurrent use.
+//
+//nolint:recvcheck // changing this would be a breaking change.
 type Client struct {
 	accountID  int
 	endpoint   string
diff --git a/internal/geoipupdate/database/reader.go b/internal/geoipupdate/database/reader.go
index b55ba76..c269a7b 100644
--- a/internal/geoipupdate/database/reader.go
+++ b/internal/geoipupdate/database/reader.go
@@ -23,14 +23,18 @@ type ReadResult struct {
 }
 
 // MarshalJSON is a custom json marshaler that strips out zero time fields.
-func (r ReadResult) MarshalJSON() ([]byte, error) {
+func (r *ReadResult) MarshalJSON() ([]byte, error) {
+	if r == nil {
+		return []byte("null"), nil
+	}
+
 	type partialResult ReadResult
 	s := &struct {
 		partialResult
 		ModifiedAt int64 `json:"modified_at,omitempty"`
 		CheckedAt  int64 `json:"checked_at,omitempty"`
 	}{
-		partialResult: partialResult(r),
+		partialResult: partialResult(*r),
 		ModifiedAt:    0,
 		CheckedAt:     0,
 	}
diff --git a/internal/geoipupdate/geoip_updater_test.go b/internal/geoipupdate/geoip_updater_test.go
index 44dfcf8..09784aa 100644
--- a/internal/geoipupdate/geoip_updater_test.go
+++ b/internal/geoipupdate/geoip_updater_test.go
@@ -283,7 +283,7 @@ func (w *mockWriter) Write(
 	return nil
 }
 
-func (w mockWriter) GetHash(editionID string) (string, error) {
+func (w *mockWriter) GetHash(editionID string) (string, error) {
 	return w.md5s[editionID], nil
 }