feat: Add noniljson Linter to Enforce omitempty for Nullable Struct Fields

.golangci.reference.yml

@@ -2567,6 +2567,7 @@ linters:
     - noctx
     - nolintlint
     - nonamedreturns
+    - noniljson
     - nosnakecase
     - nosprintfhostport
     - paralleltest
@@ -2690,6 +2691,7 @@ linters:
     - noctx
     - nolintlint
     - nonamedreturns
+    - noniljson
     - nosnakecase
     - nosprintfhostport
     - paralleltest

go.mod

@@ -87,6 +87,7 @@ require (
 	github.com/nunnatsa/ginkgolinter v0.15.2
 	github.com/polyfloyd/go-errorlint v1.4.8
 	github.com/quasilyte/go-ruleguard/dsl v0.3.22
+	github.com/rezkam/noniljson v1.0.2
 	github.com/ryancurrah/gomodguard v1.3.0
 	github.com/ryanrolds/sqlclosecheck v0.5.1
 	github.com/sanposhiho/wastedassign/v2 v2.0.7

pkg/golinters/noniljson.go

@@ -0,0 +1,19 @@
+package golinters
+
+import (
+	"github.com/rezkam/noniljson"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewNoNilJSON() *goanalysis.Linter {
+	a := noniljson.Analyzer
+
+	return goanalysis.NewLinter(
+		a.Name,
+		"checks that nullable fields in structs used for JSON marshaling use 'omitempty'",
+		[]*analysis.Analyzer{a},
+		nil,
+	)
+}

pkg/lint/lintersdb/manager.go

@@ -713,6 +713,12 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetStyle).
 			WithURL("https://github.com/firefart/nonamedreturns"),
 
+		linter.NewConfig(golinters.NewNoNilJSON()).
+			WithSince("v1.57.0").
+			WithLoadForGoAnalysis().
+			WithPresets(linter.PresetBugs).
+			WithURL("https://github.com/rezkam/noniljson"),
+
 		linter.NewConfig(golinters.NewNoSnakeCase()).
 			WithSince("v1.47.0").
 			WithPresets(linter.PresetStyle).

test/testdata/noniljson.go

@@ -0,0 +1,22 @@
+//golangcitest:args -Enoniljson
+package testdata
+
+type userData struct {
+	Name     *string           `json:"name"` // want `nullable field 'Name' in struct 'userData' must include 'omitempty' in its json tag to avoid marshaling as null`
+	Email    string            `json:"email,omitempty"`
+	Address  *string           `json:"address,omitempty"`
+	Friends  []string          `json:"friends"`  // want `nullable field 'Friends' in struct 'userData' must include 'omitempty' in its json tag to avoid marshaling as null`
+	Metadata map[string]string `json:"metadata"` // want `nullable field 'Metadata' in struct 'userData' must include 'omitempty' in its json tag to avoid marshaling as null`
+}
+
+type dynamicData struct {
+	Data interface{} `json:"data"` // want `nullable field 'Data' in struct 'dynamicData' must include 'omitempty' in its json tag to avoid marshaling as null`
+}
+
+type productData struct {
+	ID           int                    `json:"id"`
+	Description  *string                `json:"description"` // want `nullable field 'Description' in struct 'productData' must include 'omitempty' in its json tag to avoid marshaling as null`
+	Price        float64                `json:"price,omitempty"`
+	Availability []int                  `json:"availability"` // want `nullable field 'Availability' in struct 'productData' must include 'omitempty' in its json tag to avoid marshaling as null`
+	Attributes   map[string]interface{} `json:"attributes"`   // want `nullable field 'Attributes' in struct 'productData' must include 'omitempty' in its json tag to avoid marshaling as null`
+}