feat: many2many relations check

relationsCheck/relationsCheck.go

@@ -0,0 +1,89 @@
+package relationsCheck
+
+import (
+	"fmt"
+	"golang.org/x/tools/go/analysis"
+	"gormlint/common"
+	"slices"
+)
+
+// RelationsAnalyzer todo: add URL for rule
+var RelationsAnalyzer = &analysis.Analyzer{
+	Name: "GormReferencesCheck",
+	Doc:  "report about invalid references in models",
+	Run:  run,
+}
+
+func CheckTypesOfM2M(pass *analysis.Pass, modelName string, relatedModelName string, relationName string, reference common.Field, backReference common.Field) {
+	if !common.IsSlice(reference.Type) {
+		pass.Reportf(reference.Pos, "M2M relation `%s` with bad type `%s` (should be a slice)", relationName, reference.Type)
+		return
+	}
+	if !common.IsSlice(backReference.Type) {
+		pass.Reportf(backReference.Pos, "M2M relation `%s` with bad type `%s` (should be a slice)", relationName, backReference.Type)
+		return
+	}
+
+	referenceBaseType := common.ResolveBaseType(reference.Type)
+	if referenceBaseType == nil {
+		pass.Reportf(reference.Pos, "Failed to resolve field type: `%s`", reference.Type)
+		return
+	}
+	backReferenceBaseType := common.ResolveBaseType(backReference.Type)
+	if backReferenceBaseType == nil {
+		pass.Reportf(reference.Pos, "Failed to resolve type: `%s`", reference.Type)
+		return
+	}
+
+	if *backReferenceBaseType != modelName {
+		pass.Reportf(backReference.Pos, "Invalid type `%s` in M2M relation (use []*%s or self-reference)", *backReferenceBaseType, modelName)
+		return
+	}
+
+	if *referenceBaseType != relatedModelName {
+		pass.Reportf(reference.Pos, "Invalid type `%s` in M2M relation (use []*%s or self-reference)", *referenceBaseType, relatedModelName)
+	}
+}
+
+func CheckMany2Many(pass *analysis.Pass, models map[string]common.Model) {
+	// TODO: unexpected duplicated relations
+	var knownModels []string
+	for _, model := range models {
+		for _, field := range model.Fields {
+			m2mRelation := field.GetParam("many2many")
+			if m2mRelation != nil {
+				relatedModel := common.GetModelFromType(field.Type, models)
+				if relatedModel == nil {
+					pass.Reportf(field.Pos, "Failed to resolve related model type")
+					return
+				}
+
+				backReference := common.FindBackReferenceInM2M(m2mRelation.Value, *relatedModel)
+				if backReference != nil {
+					if slices.Contains(knownModels, relatedModel.Name) {
+						continue
+					} else {
+						knownModels = append(knownModels, model.Name)
+						knownModels = append(knownModels, relatedModel.Name)
+					}
+					CheckTypesOfM2M(pass, model.Name, relatedModel.Name, m2mRelation.Value, field, *backReference)
+					// TODO: check foreign key and references
+					fmt.Printf("Found M2M relation between \"%s\" and \"%s\"\n", model.Name, relatedModel.Name)
+				} else {
+					// Here you can forbid M2M relations without back-reference
+					// TODO: process m2m without backref
+				}
+			} else {
+				// TODO: check [] and process m:1
+			}
+		}
+	}
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	models := make(map[string]common.Model)
+	common.ParseModels(pass, &models)
+	CheckMany2Many(pass, models)
+
+	return nil, nil
+}