Update golangci-lint to v2.15.0 to fix flaky revive results

.golangci.yml

@@ -37,6 +37,7 @@ linters:
     # We often don't initialize all of the struct fields. This is fine
     # generally
     - exhaustruct
+    - exhaustruct_v5
 
     # We tried this linter but most places we do forced type asserts are
     # pretty safe, e.g., an atomic.Value when everything is encapsulated
@@ -739,7 +740,10 @@ formatters:
 
     gofumpt:
       module-path: github.com/maxmind/geoipupdate/v8
-      extra-rules: true
+      extra:
+        group-params: true
+        clothe-returns: true
+        balance-calls: true
 
     goimports:
       local-prefixes:

cmd/geoipupdate/version.go

@@ -1,5 +1,3 @@
-//go:build go1.12
-
 package main
 
 import (

internal/errors.go

@@ -23,8 +23,7 @@ func IsRetryableError(err error) bool {
 		return false
 	}
 
-	var httpErr HTTPError
-	if errors.As(err, &httpErr) {
+	if httpErr, ok := errors.AsType[HTTPError](err); ok {
 		return isRetryableHTTPStatusCode(httpErr.StatusCode)
 	}
 

internal/geoipupdate/config.go

@@ -387,6 +387,7 @@ func setConfigFromEnv(config *Config) error {
 // takes precedence over the variable named by key.
 func lookupFileOrEnv(key string) (string, bool, error) {
 	if path := os.Getenv(key + "_FILE"); path != "" {
+		//nolint:gosec // The user sets this path to the file to read.
 		content, err := os.ReadFile(filepath.Clean(path))
 		if err != nil {
 			return "", false, fmt.Errorf("failed to read %s_FILE: %w", key, err)

internal/geoipupdate/database/reader.go

@@ -23,19 +23,15 @@ type ReadResult struct {
 }
 
 // MarshalJSON is a custom json marshaler that strips out zero time fields.
-func (r *ReadResult) MarshalJSON() ([]byte, error) {
-	if r == nil {
-		return []byte("null"), nil
-	}
-
+func (r ReadResult) MarshalJSON() ([]byte, error) {
 	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,
 	}

internal/geoipupdate/geoip_updater_test.go

@@ -146,7 +146,8 @@ func TestRetryWhenWriting(t *testing.T) {
 			// The md5 here belongs to the tar.gz sent below.
 			metadata := []byte(
 				`{"databases":[{"edition_id":"foo-db-name",` +
-					`"md5":"83e01ba43c2a66e30cb3007c1a300c78","date":"2023-04-27"}]}`)
+					`"md5":"83e01ba43c2a66e30cb3007c1a300c78","date":"2023-04-27"}]}`,
+			)
 			_, err := w.Write(metadata)
 			assert.NoError(t, err)