feat: null safety

.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/gormlint.iml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="Go" enabled="true" />
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/inspectionProfiles/Project_Default.xml

@@ -0,0 +1,10 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="GoDfaErrorMayBeNotNil" enabled="true" level="WARNING" enabled_by_default="true">
+      <methods>
+        <method importPath="github.com/fatih/structtag" receiver="*Tags" name="Get" />
+      </methods>
+    </inspection_tool>
+  </profile>
+</component>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/gormlint.iml" filepath="$PROJECT_DIR$/.idea/gormlint.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+    <mapping directory="$PROJECT_DIR$/cmd/gormlint" vcs="Git" />
+  </component>
+</project>

cmd/gormlint/main.go

@@ -0,0 +1,10 @@
+package main
+
+import (
+	"golang.org/x/tools/go/analysis/singlechecker"
+	"gormlint/nullSafetyCheck"
+)
+
+func main() {
+	singlechecker.Main(nullSafetyCheck.NullSafetyAnalyzer)
+}

common/nullSafetyCheck.go

@@ -0,0 +1,68 @@
+package common
+
+import (
+	"errors"
+	"github.com/fatih/structtag"
+	"go/ast"
+	"golang.org/x/tools/go/analysis"
+)
+
+func isPointerType(typeExpr ast.Expr) bool {
+	isPointer := false
+	if _, ok := typeExpr.(*ast.StarExpr); ok {
+		isPointer = true
+	}
+	return isPointer
+}
+
+func isGormValueNullable(tags *structtag.Tags) (*bool, error) {
+	gormTag, err := tags.Get("gorm")
+	if gormTag == nil {
+		return nil, nil
+	}
+
+	gormTag.Options = append([]string{gormTag.Name}, gormTag.Options...)
+
+	if err != nil {
+		return nil, nil
+	}
+
+	nullTagExist := gormTag.HasOption("null")
+	notNullTagExist := gormTag.HasOption("not null")
+
+	if nullTagExist == notNullTagExist && nullTagExist == true {
+		return nil, errors.New(`tags "null" and "not null" are specified at one field`)
+	}
+
+	if nullTagExist {
+		return PointerOf(true), nil
+	} else if notNullTagExist {
+		return PointerOf(false), nil
+	} else {
+		return PointerOf(false), nil
+	}
+}
+
+func CheckFieldNullConsistency(pass analysis.Pass, field ast.Field, structName string, structTags string) {
+	tags, err := structtag.Parse(structTags)
+	if err != nil {
+		pass.Reportf(field.Pos(), "Invalid structure tag: %s", err)
+	}
+	if tags == nil {
+		return
+	}
+
+	isFieldNullable := isPointerType(field.Type)
+	isColumnNullable, err := isGormValueNullable(tags)
+
+	if err != nil {
+		pass.Reportf(field.Pos(), "Null safety error: %s", err)
+	}
+	if isColumnNullable == nil {
+		return
+	}
+
+	if isFieldNullable != *isColumnNullable {
+		pass.Reportf(field.Pos(), "Null safety error in \"%s\" model, field \"%s\": column nullable policy doesn't match to tag nullable policy", structName, field.Names[0].Name)
+	}
+}

common/pointerOf.go

@@ -0,0 +1,5 @@
+package common
+
+func PointerOf[T any](v T) *T {
+	return &v
+}

common/unnamedChecks.go

@@ -0,0 +1,18 @@
+package common
+
+import (
+	"go/ast"
+	"golang.org/x/tools/go/analysis"
+)
+
+func CheckUnnamedModel(pass analysis.Pass, typeSpec ast.TypeSpec) {
+	if typeSpec.Name == nil {
+		pass.Reportf(typeSpec.Pos(), "Unnamed model\n")
+	}
+}
+
+func CheckUnnamedField(pass analysis.Pass, structName string, field ast.Field) {
+	if len(field.Names) == 0 {
+		pass.Reportf(field.Pos(), "Struct \"%s\" has unnamed field", structName)
+	}
+}

go.mod

@@ -0,0 +1,15 @@
+module gormlint
+
+go 1.23.2
+
+require golang.org/x/tools v0.28.0
+
+require (
+	github.com/fatih/color v1.18.0 // indirect
+	github.com/fatih/structtag v1.2.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	golang.org/x/mod v0.22.0 // indirect
+	golang.org/x/sync v0.10.0 // indirect
+	golang.org/x/sys v0.28.0 // indirect
+)

go.sum

@@ -0,0 +1,21 @@
+github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
+github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
+github.com/fatih/structtag v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
+github.com/fatih/structtag v1.2.0/go.mod h1:mBJUNpUnHmRKrKlQQlmCrh5PuhftFbNv8Ys4/aAZl94=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=
+golang.org/x/mod v0.22.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
+golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
+golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
+golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.28.0 h1:WuB6qZ4RPCQo5aP3WdKZS7i595EdWqWR8vqJTlwTVK8=
+golang.org/x/tools v0.28.0/go.mod h1:dcIOrVd3mfQKTgrDVQHqCPMWy6lnhfhtX3hLXYVLfRw=

models/testdata.go

@@ -0,0 +1,26 @@
+package models
+
+type Order struct {
+	Id            uint `gorm:"primaryKey"`
+	Status        string
+	ProductTypeId uint
+	ProductType   ProductType
+	ProductAmount uint
+	Description   string
+	CustomerId    uint `gorm:"null;foreignKey:CustomerId;"`
+	Customer      Customer
+	CreatedAt     int64 `gorm:"autoCreateTime"`
+	DeadlineDate  int64
+}
+
+type ProductType struct {
+	Id   uint `gorm:"primaryKey"`
+	Name string
+}
+
+type Customer struct {
+	Id      uint `gorm:"primaryKey"`
+	Title   string
+	Contact string
+	Orders  []Order `gorm:"foreignKey:CustomerId"`
+}

nullSafetyCheck/nullSafetyCheck.go

@@ -0,0 +1,44 @@
+package nullSafetyCheck
+
+import (
+	"go/ast"
+	"golang.org/x/tools/go/analysis"
+	"gormlint/common"
+	"strings"
+)
+
+var NullSafetyAnalyzer = &analysis.Analyzer{
+	Name: "nullSafety",
+	Doc:  "reports inconsistency of nullable values",
+	Run:  run,
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	for _, file := range pass.Files {
+		ast.Inspect(file, func(node ast.Node) bool {
+			typeSpec, ok := node.(*ast.TypeSpec)
+			if !ok {
+				return true
+			}
+			structure, ok := typeSpec.Type.(*ast.StructType)
+			if !ok {
+				return true
+			}
+
+			common.CheckUnnamedModel(*pass, *typeSpec)
+
+			for _, field := range structure.Fields.List {
+				common.CheckUnnamedField(*pass, typeSpec.Name.Name, *field)
+				if field.Tag != nil {
+					tagWithoutQuotes := field.Tag.Value[1 : len(field.Tag.Value)-1]
+					tagWithoutSemicolons := strings.ReplaceAll(tagWithoutQuotes, ";", ",")
+					common.CheckFieldNullConsistency(*pass, *field, typeSpec.Name.Name, tagWithoutSemicolons)
+				} else {
+					// TODO: check necessary tags for some fields
+				}
+			}
+			return false
+		})
+	}
+	return nil, nil
+}