fix(09): WR-16 resolve model columns through embedded structs and explicit column tags

docs/backend/admin-controllers.md

@@ -154,7 +154,7 @@ func (p *BlogPlugin) Settings() []pact.SettingsItem {
 summer make:admin-controller acme.blog Posts
 ```
 
-The generated controller requires the permission `acme.blog.access_posts`, so declare it in the plugin's `pact.HasPermissions` or the admin API refuses to start with an unknown-permission error. Its `NewRecord` returns `nil` until you return the model, and the list and every write answer 500 until then. The controller ID maps to the admin API path: `acme.blog.posts` is served under `<prefix>/api/v1/acme/blog/posts`. The admin prefix is `backend.uri`, `/backend` by default. A model's `Fillable` method decides which form fields the API may write; see [Forms](forms.md).
+The generated controller requires the permission `acme.blog.access_posts`, so declare it in the plugin's `pact.HasPermissions` or the admin API refuses to start with an unknown-permission error. Its `NewRecord` returns `nil` until you return the model, and the list and every write answer 500 until then. The controller ID maps to the admin API path: `acme.blog.posts` is served under `<prefix>/api/v1/acme/blog/posts`. The admin prefix is `backend.uri`, `/backend` by default. A model's `Fillable` method decides which form fields the API may write; see [Forms](forms.md). The admin finds a model's columns through its struct fields, including those of an embedded struct such as `gorm.Model`. A field with a `gorm:"column:..."` tag is known by that column alone; an untagged field is known by GORM's default column name.
 
 ## Compilation at boot
 

modules/cabana/crud.go

@@ -785,21 +785,9 @@ func projectRecord(cc *CompiledController, model any) map[string]any {
 }
 
 func modelColumns(model any) map[string]struct{} {
-	t := reflect.TypeOf(model)
-	for t != nil && t.Kind() == reflect.Pointer {
-		t = t.Elem()
-	}
 	cols := map[string]struct{}{}
-	if t == nil || t.Kind() != reflect.Struct {
-		return cols
-	}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath != "" {
-			continue
-		}
-		name := gormColumn(field)
-		if name != "" {
+	for _, mf := range modelFields(reflect.TypeOf(model)) {
+		if name := gormColumn(mf.Field); name != "" {
 			cols[name] = struct{}{}
 		}
 	}
@@ -873,9 +861,9 @@ func castPK(model any, n uint) any {
 	if t == nil || t.Kind() != reflect.Struct {
 		return n
 	}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if !strings.Contains(field.Tag.Get("gorm"), "primaryKey") {
+	for _, mf := range modelFields(t) {
+		field := mf.Field
+		if !hasPrimaryKeyTag(field) {
 			continue
 		}
 		switch field.Type.Kind() {

modules/cabana/filter_schema.go

@@ -319,9 +319,9 @@ func modelColumnType(ctl pact.AdminController, column string) (reflect.Type, boo
 	if t == nil || t.Kind() != reflect.Struct {
 		return nil, false
 	}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath != "" || isListRelation(field.Type) {
+	for _, mf := range modelFields(t) {
+		field := mf.Field
+		if isListRelation(field.Type) {
 			continue
 		}
 		name := gormColumn(field)

modules/cabana/http.go

@@ -842,21 +842,38 @@ func projectRow(row any, controller pact.AdminController, cols []ListColumn) map
 	return out
 }
 
+// fieldByColumn returns the model field stored in column, looking through
+// embedded structs such as gorm.Model. A field with an explicit `column:` tag is
+// matched by that tag alone; only an untagged field falls back to its Go name
+// (case-insensitive) or GORM's default column name for it, and a shallower
+// field shadows an embedded one, as in Go.
 func fieldByColumn(v reflect.Value, column string) reflect.Value {
 	if v.Kind() != reflect.Struct {
 		return reflect.Value{}
 	}
-	t := v.Type()
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath != "" {
-			continue
-		}
-		if gormColumn(field) == column || strings.EqualFold(field.Name, column) {
-			return v.Field(i)
+	fields := modelFields(v.Type())
+	best := -1
+	for i := range fields {
+		if gormColumn(fields[i].Field) == column && (best < 0 || len(fields[i].Path) < len(fields[best].Path)) {
+			best = i
 		}
 	}
-	return reflect.Value{}
+	if best < 0 {
+		for i := range fields {
+			untagged := gormColumn(fields[i].Field) == ""
+			if untagged && (strings.EqualFold(fields[i].Field.Name, column) || defaultColumnName(fields[i].Field) == column) && (best < 0 || len(fields[i].Path) < len(fields[best].Path)) {
+				best = i
+			}
+		}
+	}
+	if best < 0 {
+		return reflect.Value{}
+	}
+	field, err := v.FieldByIndexErr(fields[best].Path)
+	if err != nil {
+		return reflect.Value{}
+	}
+	return field
 }
 
 func gormColumn(field reflect.StructField) string {

modules/cabana/list_schema.go

@@ -397,11 +397,8 @@ func listModelContract(ctl pact.AdminController) (map[string]struct{}, map[strin
 	}
 	cols := map[string]struct{}{}
 	rels := map[string]struct{}{}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath != "" {
-			continue
-		}
+	for _, mf := range modelFields(t) {
+		field := mf.Field
 		if isListRelation(field.Type) {
 			rels[field.Name] = struct{}{}
 			// Winter YAML spells relations in lowercase (relation: genre)

modules/cabana/model_fields.go

@@ -0,0 +1,98 @@
+package cabana
+
+import (
+	"database/sql"
+	"database/sql/driver"
+	"reflect"
+	"strings"
+	"sync"
+	"time"
+
+	"gorm.io/gorm/schema"
+)
+
+// modelField is an exported struct field of a model together with its index
+// path from the model type, so a field promoted from an embedded struct
+// (gorm.Model, a shared timestamps struct) is reachable like a top-level one.
+type modelField struct {
+	Field reflect.StructField
+	Path  []int
+}
+
+var modelFieldCache sync.Map // reflect.Type -> []modelField
+
+// modelFields lists the exported fields of the struct type behind t in
+// declaration order, with anonymous (embedded) structs flattened in place.
+// Embedded scalar-like structs (time.Time, sql.Null*, anything that is a
+// Scanner or Valuer) stay single fields. It returns nil for a non-struct.
+func modelFields(t reflect.Type) []modelField {
+	for t != nil && t.Kind() == reflect.Pointer {
+		t = t.Elem()
+	}
+	if t == nil || t.Kind() != reflect.Struct {
+		return nil
+	}
+	if cached, ok := modelFieldCache.Load(t); ok {
+		return cached.([]modelField)
+	}
+	fields := flattenModelFields(t, nil, 0)
+	modelFieldCache.Store(t, fields)
+	return fields
+}
+
+func flattenModelFields(t reflect.Type, prefix []int, depth int) []modelField {
+	var out []modelField
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		path := append(append([]int(nil), prefix...), i)
+		if f.Anonymous && depth < 5 {
+			if inner := embeddedStructType(f.Type); inner != nil {
+				out = append(out, flattenModelFields(inner, path, depth+1)...)
+				continue
+			}
+		}
+		if f.PkgPath != "" {
+			continue
+		}
+		out = append(out, modelField{Field: f, Path: path})
+	}
+	return out
+}
+
+var (
+	scannerType = reflect.TypeOf((*sql.Scanner)(nil)).Elem()
+	valuerType  = reflect.TypeOf((*driver.Valuer)(nil)).Elem()
+	timeType    = reflect.TypeOf(time.Time{})
+)
+
+// embeddedStructType returns the struct type to flatten for an embedded field,
+// or nil when the field is a single value.
+func embeddedStructType(t reflect.Type) reflect.Type {
+	if t.Kind() == reflect.Pointer {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Struct || t == timeType {
+		return nil
+	}
+	ptr := reflect.PointerTo(t)
+	if ptr.Implements(scannerType) || t.Implements(valuerType) || ptr.Implements(valuerType) {
+		return nil
+	}
+	return t
+}
+
+// hasPrimaryKeyTag reports whether a field's gorm tag declares it the primary
+// key. GORM reads the key case-insensitively (gorm.Model writes "primarykey").
+func hasPrimaryKeyTag(field reflect.StructField) bool {
+	for _, part := range strings.Split(field.Tag.Get("gorm"), ";") {
+		if strings.EqualFold(strings.TrimSpace(part), "primarykey") {
+			return true
+		}
+	}
+	return false
+}
+
+// defaultColumnName is GORM's default column for an untagged field.
+func defaultColumnName(field reflect.StructField) string {
+	return schema.NamingStrategy{}.ColumnName("", field.Name)
+}

modules/cabana/model_fields_test.go

@@ -0,0 +1,86 @@
+package cabana
+
+import (
+	"reflect"
+	"testing"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+type embeddedBase struct {
+	ID        uint      `gorm:"primarykey"`
+	CreatedAt time.Time `gorm:"column:created_at"`
+}
+
+type embeddedModel struct {
+	embeddedBase
+	Name string `gorm:"column:name"`
+}
+
+type gormModelRow struct {
+	gorm.Model
+	Name string `gorm:"column:name"`
+}
+
+type retaggedModel struct {
+	Name  string `gorm:"column:title"`
+	Title string `gorm:"column:name"`
+	Plain string
+}
+
+// TestModelHelpersLookThroughEmbeddedStructs pins WR-16: the reflection helpers
+// that resolve columns see fields promoted from an embedded struct such as
+// gorm.Model, so list rows keep their id and timestamps and a relation link
+// writes the real owner key instead of 0.
+func TestModelHelpersLookThroughEmbeddedStructs(t *testing.T) {
+	row := &embeddedModel{embeddedBase: embeddedBase{ID: 7, CreatedAt: time.Unix(1700000000, 0).UTC()}, Name: "n"}
+	if got := primaryColumn(row); got != "id" {
+		t.Fatalf("primaryColumn = %q, want id (the embedded primarykey field)", got)
+	}
+	if got := pkUint(row); got != 7 {
+		t.Fatalf("pkUint = %d, want 7", got)
+	}
+	cols := modelColumns(row)
+	for _, want := range []string{"created_at", "name"} {
+		if _, ok := cols[want]; !ok {
+			t.Fatalf("modelColumns = %v, missing %s", cols, want)
+		}
+	}
+	projected := projectRow(row, nil, []ListColumn{{Key: "name"}, {Key: "created_at"}})
+	if projected["id"] != uint(7) || projected["name"] != "n" || projected["created_at"] == nil {
+		t.Fatalf("projectRow = %#v, want the embedded id and created_at", projected)
+	}
+	if castPK(row, 9) != uint(9) {
+		t.Fatalf("castPK = %#v", castPK(row, 9))
+	}
+
+	gm := &gormModelRow{Model: gorm.Model{ID: 11}, Name: "g"}
+	if primaryColumn(gm) != "id" || pkUint(gm) != 11 {
+		t.Fatalf("gorm.Model primary key = %q/%d, want id/11", primaryColumn(gm), pkUint(gm))
+	}
+	if !fieldByColumn(reflect.ValueOf(gm).Elem(), "updated_at").IsValid() {
+		t.Fatal("gorm.Model's UpdatedAt is not reachable by column")
+	}
+}
+
+// TestFieldByColumnTagBeatsGoName pins the other half of WR-16: a field with an
+// explicit column tag is matched by that tag alone, never by its Go name.
+func TestFieldByColumnTagBeatsGoName(t *testing.T) {
+	row := retaggedModel{Name: "in-title-column", Title: "in-name-column", Plain: "p"}
+	v := reflect.ValueOf(row)
+	if got := fieldByColumn(v, "name"); !got.IsValid() || got.String() != "in-name-column" {
+		t.Fatalf("column name resolved to %v, want the field tagged column:name", got)
+	}
+	if got := fieldByColumn(v, "title"); !got.IsValid() || got.String() != "in-title-column" {
+		t.Fatalf("column title resolved to %v, want the field tagged column:title", got)
+	}
+	if got := fieldByColumn(v, "plain"); !got.IsValid() || got.String() != "p" {
+		t.Fatalf("an untagged field must still match its Go name case-insensitively, got %v", got)
+	}
+	if got := fieldByColumn(reflect.ValueOf(struct {
+		Name string `gorm:"column:title"`
+	}{Name: "x"}), "name"); got.IsValid() {
+		t.Fatalf("a tagged field matched by its Go name: %v", got)
+	}
+}

modules/cabana/query.go

@@ -477,24 +477,14 @@ func relationFieldName(model any, relation string) (string, bool) {
 }
 
 func primaryColumn(model any) string {
-	t := reflect.TypeOf(model)
-	for t != nil && t.Kind() == reflect.Pointer {
-		t = t.Elem()
-	}
-	if t == nil || t.Kind() != reflect.Struct {
-		return "id"
-	}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath != "" {
+	for _, mf := range modelFields(reflect.TypeOf(model)) {
+		if !hasPrimaryKeyTag(mf.Field) {
 			continue
 		}
-		if strings.Contains(field.Tag.Get("gorm"), "primaryKey") {
-			if name := gormColumn(field); name != "" {
-				return name
-			}
-			return field.Name
+		if name := gormColumn(mf.Field); name != "" {
+			return name
 		}
+		return defaultColumnName(mf.Field)
 	}
 	return "id"
 }

modules/cabana/relation_field.go

@@ -245,10 +245,9 @@ func structFieldByColumn(model any, column string) (reflect.StructField, bool) {
 	if t == nil || t.Kind() != reflect.Struct {
 		return reflect.StructField{}, false
 	}
-	for i := 0; i < t.NumField(); i++ {
-		field := t.Field(i)
-		if field.PkgPath == "" && gormColumn(field) == column {
-			return field, true
+	for _, mf := range modelFields(t) {
+		if gormColumn(mf.Field) == column {
+			return mf.Field, true
 		}
 	}
 	return reflect.StructField{}, false