Complete ORM core: _inherits, Related write-back, Copy, constraints

Batch 1 (quick-fixes):
- Field.Copy attribute + IsCopyable() method for copy control
- Constraints now run in Write() (was only Create — bug fix)
- Readonly fields silently skipped in Write()
- active_test: auto-filter archived records in Search()

Batch 2 (Related field write-back):
- preprocessRelatedWrites() follows FK chain and writes to target model
- Enables Settings page to edit company name/address/etc.
- Loop protection via _write_related_depth context counter

Batch 3 (_inherits delegation):
- SetupAllInherits() generates Related fields from parent models
- preprocessInheritsCreate() auto-creates parent records on Create
- Declared on res.users, res.company, product.product
- Called in LoadModules before compute setup

Batch 4 (Copy method):
- Recordset.Copy(defaults) with blacklist, IsCopyable check
- M2M re-linking, rec_name "(copy)" suffix
- Replaces simplified copy case in server dispatch

Batch 5 (Onchange compute):
- RunOnchangeComputes() triggers dependent computes on field change
- Virtual record (ID=-1) with client values in cache
- Integrated into onchange RPC handler

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pkg/modules/graph.go

@@ -105,7 +105,10 @@ func LoadModules(moduleNames []string) error {
 		}
 	}
 
-	// Phase 3: Build computed field dependency maps
+	// Phase 3: Generate Related fields for _inherits delegation
+	orm.SetupAllInherits()
+
+	// Phase 4: Build computed field dependency maps
 	orm.SetupAllComputes()
 
 	return nil

pkg/orm/compute.go

@@ -196,6 +196,74 @@ func joinStrings(s []string, sep string) string {
 	return result
 }
 
+// RunOnchangeComputes runs computed fields that depend on changed fields.
+// Used by the onchange RPC to recompute values when form fields change.
+// Mirrors: odoo/orm/models.py BaseModel._onchange_eval()
+//
+// Creates a virtual record (ID=-1) with the client's values in cache,
+// then runs any compute functions whose dependencies include the changed fields.
+func RunOnchangeComputes(m *Model, env *Environment, currentVals Values, changedFields []string) Values {
+	result := make(Values)
+	if m == nil || len(m.dependencyMap) == 0 {
+		return result
+	}
+
+	// Find which computed fields need recomputation
+	toRecompute := make(map[string]bool)
+	for _, fname := range changedFields {
+		if deps, ok := m.dependencyMap[fname]; ok {
+			for _, computedField := range deps {
+				toRecompute[computedField] = true
+			}
+		}
+	}
+
+	if len(toRecompute) == 0 {
+		return result
+	}
+
+	// Populate cache with current form values so computes can read them
+	fakeID := int64(-1)
+	for k, v := range currentVals {
+		env.cache.Set(m.Name(), fakeID, k, v)
+	}
+	defer env.cache.InvalidateRecord(m.Name(), fakeID)
+
+	// Create virtual recordset
+	rs := &Recordset{env: env, model: m, ids: []int64{fakeID}}
+
+	// Track which compute functions we've already called (multiple fields can share one function)
+	seen := make(map[string]bool)
+
+	for fieldName := range toRecompute {
+		f := m.GetField(fieldName)
+		if f == nil || f.Compute == "" {
+			continue
+		}
+		// Don't call the same compute function twice
+		if seen[f.Compute] {
+			continue
+		}
+		seen[f.Compute] = true
+
+		fn, ok := m.computes[fieldName]
+		if !ok {
+			continue
+		}
+
+		computed, err := fn(rs)
+		if err != nil {
+			// Non-fatal: skip failed computes during onchange
+			continue
+		}
+		for k, v := range computed {
+			result[k] = v
+		}
+	}
+
+	return result
+}
+
 // SetupAllComputes calls SetupComputes on all registered models.
 func SetupAllComputes() {
 	for _, m := range Registry.Models() {

pkg/orm/field.go

@@ -60,6 +60,9 @@ type Field struct {
 	// Translation
 	Translate bool // Field supports multi-language
 
+	// Copy
+	Copy bool // Whether this field is copied on record duplication
+
 	// Groups (access control)
 	Groups string // Comma-separated group XML IDs
 
@@ -97,6 +100,27 @@ func (f *Field) IsStored() bool {
 	return f.Type.IsStored()
 }
 
+// IsCopyable returns true if this field should be copied on record duplication.
+// Mirrors: odoo/orm/fields.py Field.copy
+func (f *Field) IsCopyable() bool {
+	// If explicitly set, use that
+	if f.Copy {
+		return true
+	}
+	// Defaults: non-copyable for computed, O2M, id, timestamps
+	if f.Name == "id" || f.Name == "create_uid" || f.Name == "create_date" ||
+		f.Name == "write_uid" || f.Name == "write_date" || f.Name == "password" {
+		return false
+	}
+	if f.Compute != "" && !f.Store {
+		return false
+	}
+	if f.Type == TypeOne2many {
+		return false
+	}
+	return true
+}
+
 // IsRelational returns true for relational field types.
 func (f *Field) IsRelational() bool {
 	return f.Type.IsRelational()
@@ -130,6 +154,7 @@ type FieldOpts struct {
 	OnDelete      OnDelete
 	CurrencyField string
 	Translate     bool
+	Copy          bool
 	Groups        string
 }
 
@@ -160,6 +185,7 @@ func newField(name string, typ FieldType, opts FieldOpts) *Field {
 		OnDelete:      opts.OnDelete,
 		CurrencyField: opts.CurrencyField,
 		Translate:     opts.Translate,
+		Copy:          opts.Copy,
 		Groups:        opts.Groups,
 		column:        name,
 	}

pkg/orm/inherits.go

@@ -0,0 +1,152 @@
+package orm
+
+import (
+	"fmt"
+	"log"
+)
+
+// SetupAllInherits generates Related fields for all models with _inherits declarations.
+// Must be called after all models are registered but before computes are set up.
+// Mirrors: odoo/orm/model_classes.py _add_inherited_fields()
+func SetupAllInherits() {
+	for _, m := range Registry.Models() {
+		if len(m.inherits) == 0 {
+			continue
+		}
+		setupModelInherits(m)
+	}
+}
+
+func setupModelInherits(m *Model) {
+	for parentName, fkField := range m.inherits {
+		parent := Registry.Get(parentName)
+		if parent == nil {
+			log.Printf("inherits: parent model %q not found for %s", parentName, m.Name())
+			continue
+		}
+
+		// Verify FK field exists on child
+		fkDef := m.GetField(fkField)
+		if fkDef == nil {
+			log.Printf("inherits: FK field %q not found on %s", fkField, m.Name())
+			continue
+		}
+
+		// For each parent field, create a Related field on child if not already defined
+		inherited := 0
+		for _, fname := range parent.fieldOrder {
+			// Skip magic fields (child has its own)
+			if fname == "id" || fname == "display_name" ||
+				fname == "create_uid" || fname == "create_date" ||
+				fname == "write_uid" || fname == "write_date" {
+				continue
+			}
+
+			// Don't override fields already defined on child
+			if existing := m.GetField(fname); existing != nil {
+				continue
+			}
+
+			pf := parent.GetField(fname)
+			if pf == nil {
+				continue
+			}
+
+			// Create Related field: "fk_field.field_name"
+			relatedPath := fkField + "." + fname
+
+			inheritedField := &Field{
+				Name:          fname,
+				Type:          pf.Type,
+				String:        pf.String,
+				Help:          pf.Help,
+				Related:       relatedPath,
+				Comodel:       pf.Comodel,
+				InverseField:  pf.InverseField,
+				Selection:     pf.Selection,
+				CurrencyField: pf.CurrencyField,
+				Readonly:      pf.Readonly,
+				Required:      false, // Inherited fields are not required on child
+				model:         m,
+				column:        fname,
+			}
+
+			// Add to model's field maps
+			m.fields[fname] = inheritedField
+			m.allFields[fname] = inheritedField
+			m.fieldOrder = append(m.fieldOrder, fname)
+			inherited++
+		}
+
+		log.Printf("inherits: %s inherits %d fields from %s via %s",
+			m.Name(), inherited, parentName, fkField)
+	}
+}
+
+// preprocessInheritsCreate separates inherited field values and creates/updates parent records.
+// Must be called in Create() BEFORE ApplyDefaults.
+// Mirrors: odoo/orm/models.py create() _inherits handling
+func preprocessInheritsCreate(env *Environment, m *Model, vals Values) error {
+	if len(m.inherits) == 0 {
+		return nil
+	}
+
+	for parentName, fkField := range m.inherits {
+		parent := Registry.Get(parentName)
+		if parent == nil {
+			continue
+		}
+
+		// Separate parent vals from child vals
+		parentVals := make(Values)
+		for fieldName, val := range vals {
+			// Check if this field belongs to parent (not child's own stored field)
+			childField := m.fields[fieldName]
+			parentField := parent.GetField(fieldName)
+
+			if parentField != nil && fieldName != fkField &&
+				(childField == nil || childField.Related != "") {
+				parentVals[fieldName] = val
+				delete(vals, fieldName)
+			}
+		}
+
+		// Check if FK is already provided
+		fkVal, hasFk := vals[fkField]
+		if hasFk && fkVal != nil {
+			// FK provided — update existing parent record with any inherited vals
+			fkID := int64(0)
+			switch v := fkVal.(type) {
+			case float64:
+				fkID = int64(v)
+			case int64:
+				fkID = v
+			case int32:
+				fkID = int64(v)
+			}
+			if fkID > 0 && len(parentVals) > 0 {
+				parentRS := env.Model(parentName).Browse(fkID)
+				if err := parentRS.Write(parentVals); err != nil {
+					return fmt.Errorf("inherits: update %s(%d): %w", parentName, fkID, err)
+				}
+			}
+		} else {
+			// No FK — create parent record first
+			if len(parentVals) == 0 {
+				// Need at least something for the parent (e.g., name)
+				// Check if name is in child vals but not moved to parent
+				if nameVal, ok := vals["name"]; ok {
+					parentVals["name"] = nameVal
+				}
+			}
+			parentRS := env.Model(parentName)
+			created, err := parentRS.Create(parentVals)
+			if err != nil {
+				return fmt.Errorf("inherits: create %s: %w", parentName, err)
+			}
+			vals[fkField] = created.ID()
+		}
+	}
+
+	return nil
+}

pkg/orm/recordset.go

@@ -94,6 +94,11 @@ func (rs *Recordset) WithContext(ctx map[string]interface{}) *Recordset {
 func (rs *Recordset) Create(vals Values) (*Recordset, error) {
 	m := rs.model
 
+	// Handle _inherits: separate parent vals and create/update parent records
+	if err := preprocessInheritsCreate(rs.env, m, vals); err != nil {
+		return nil, err
+	}
+
 	// Phase 1: Apply defaults for missing fields
 	ApplyDefaults(m, vals)
 
@@ -211,6 +216,96 @@ func (rs *Recordset) Create(vals Values) (*Recordset, error) {
 	return result, nil
 }
 
+// preprocessRelatedWrites handles write-back for Related fields.
+// When writing to a Related field (e.g., "company_id.name"), this function
+// follows the FK chain and writes to the target model instead.
+// Mirrors: odoo/orm/fields.py _inverse_related()
+func preprocessRelatedWrites(env *Environment, m *Model, ids []int64, vals Values) error {
+	// Prevent infinite recursion
+	depth := 0
+	if d, ok := env.context["_write_related_depth"]; ok {
+		if di, ok := d.(int); ok {
+			depth = di
+		}
+	}
+	if depth > 5 {
+		return nil // Safety: max recursion depth
+	}
+
+	var relatedFields []string
+	for fieldName := range vals {
+		f := m.GetField(fieldName)
+		if f != nil && f.Related != "" && !f.IsStored() {
+			relatedFields = append(relatedFields, fieldName)
+		}
+	}
+
+	if len(relatedFields) == 0 {
+		return nil
+	}
+
+	// Read FK values for the records being written
+	// We need the FK IDs to know which parent records to update
+	for _, fieldName := range relatedFields {
+		f := m.GetField(fieldName)
+		parts := strings.Split(f.Related, ".")
+		if len(parts) != 2 {
+			delete(vals, fieldName) // Can't handle multi-hop yet, skip
+			continue
+		}
+		fkFieldName := parts[0]
+		targetFieldName := parts[1]
+
+		fkDef := m.GetField(fkFieldName)
+		if fkDef == nil || fkDef.Type != TypeMany2one || fkDef.Comodel == "" {
+			delete(vals, fieldName)
+			continue
+		}
+
+		value := vals[fieldName]
+		delete(vals, fieldName) // Remove from vals — no local column
+
+		// Read FK IDs for all records
+		var fkIDs []int64
+		for _, id := range ids {
+			var fkID *int64
+			env.tx.QueryRow(env.ctx,
+				fmt.Sprintf(`SELECT %q FROM %q WHERE id = $1`, fkDef.Column(), m.Table()),
+				id,
+			).Scan(&fkID)
+			if fkID != nil && *fkID > 0 {
+				fkIDs = append(fkIDs, *fkID)
+			}
+		}
+
+		if len(fkIDs) == 0 {
+			continue
+		}
+
+		// Deduplicate
+		seen := make(map[int64]bool)
+		var uniqueIDs []int64
+		for _, id := range fkIDs {
+			if !seen[id] {
+				seen[id] = true
+				uniqueIDs = append(uniqueIDs, id)
+			}
+		}
+
+		// Write to target model with increased depth
+		depthEnv := env.WithContext(map[string]interface{}{
+			"_write_related_depth": depth + 1,
+		})
+		targetRS := &Recordset{env: depthEnv, model: Registry.MustGet(fkDef.Comodel), ids: uniqueIDs}
+		if err := targetRS.Write(Values{targetFieldName: value}); err != nil {
+			return fmt.Errorf("related write-back %s.%s → %s.%s: %w",
+				m.Name(), fieldName, fkDef.Comodel, targetFieldName, err)
+		}
+	}
+
+	return nil
+}
+
 // Write updates the records in this recordset.
 // Mirrors: records.write(vals)
 func (rs *Recordset) Write(vals Values) error {
@@ -230,11 +325,20 @@ func (rs *Recordset) Write(vals Values) error {
 	}
 	vals["write_date"] = "NOW()" // Will be handled specially
 
+	// Handle Related field write-back (must happen before building SET clauses)
+	if err := preprocessRelatedWrites(rs.env, m, rs.ids, vals); err != nil {
+		return err
+	}
+
 	for _, name := range m.fieldOrder {
 		f := m.fields[name]
 		if name == "id" || !f.IsStored() {
 			continue
 		}
+		// Skip readonly fields (like Python Odoo, silently ignore)
+		if f.Readonly && name != "write_uid" && name != "write_date" {
+			continue
+		}
 		val, exists := vals[name]
 		if !exists {
 			continue
@@ -294,6 +398,15 @@ func (rs *Recordset) Write(vals Values) error {
 		return err
 	}
 
+	// Run constraints after write (mirrors Create constraint check)
+	for _, constraint := range m.Constraints {
+		for _, id := range rs.ids {
+			if err := constraint(rs.Browse(id)); err != nil {
+				return err
+			}
+		}
+	}
+
 	return nil
 }
 
@@ -590,6 +703,25 @@ func (rs *Recordset) Search(domain Domain, opts ...SearchOpts) (*Recordset, erro
 	m := rs.model
 	opt := mergeSearchOpts(opts)
 
+	// Auto-filter archived records unless active_test=false in context
+	// Mirrors: odoo/orm/models.py BaseModel._where_calc()
+	if activeField := m.GetField("active"); activeField != nil {
+		activeTest := true
+		if v, ok := rs.env.context["active_test"]; ok {
+			if b, ok := v.(bool); ok {
+				activeTest = b
+			}
+		}
+		if activeTest {
+			activeLeaf := Leaf("active", "=", true)
+			if len(domain) == 0 {
+				domain = Domain{activeLeaf}
+			} else {
+				domain = append(Domain{OpAnd}, append(domain, activeLeaf)...)
+			}
+		}
+	}
+
 	// Apply record rules (e.g., multi-company filter)
 	domain = ApplyRecordRules(rs.env, m, domain)
 
@@ -749,6 +881,88 @@ func (rs *Recordset) Records() []*Recordset {
 	return result
 }
 
+// Copy duplicates a singleton record, returning the new record.
+// Mirrors: odoo/orm/models.py BaseModel.copy()
+//
+//	new_partner = partner.Copy(orm.Values{"name": "New Name"})
+func (rs *Recordset) Copy(defaults Values) (*Recordset, error) {
+	if err := rs.Ensure(); err != nil {
+		return nil, err
+	}
+	m := rs.model
+
+	// Read all stored fields
+	records, err := rs.Read(nil)
+	if err != nil || len(records) == 0 {
+		return nil, fmt.Errorf("orm: copy: record %s(%d) not found", m.name, rs.ids[0])
+	}
+	original := records[0]
+
+	// Blacklisted fields (never copied)
+	blacklist := map[string]bool{
+		"id": true, "create_uid": true, "create_date": true,
+		"write_uid": true, "write_date": true, "display_name": true,
+		"password": true, "password_crypt": true,
+	}
+
+	// Also blacklist _inherits FK fields (parent will be copied separately)
+	for _, fkField := range m.inherits {
+		blacklist[fkField] = true
+	}
+
+	newVals := make(Values)
+
+	for _, name := range m.fieldOrder {
+		if blacklist[name] {
+			continue
+		}
+		f := m.fields[name]
+		if f == nil || !f.IsCopyable() || !f.IsStored() {
+			continue
+		}
+
+		val, exists := original[name]
+		if !exists || val == nil {
+			continue
+		}
+
+		switch f.Type {
+		case TypeMany2many:
+			// Re-link existing M2M entries (don't duplicate targets)
+			if ids, ok := val.([]int64); ok && len(ids) > 0 {
+				cmds := make([]interface{}, len(ids))
+				for i, id := range ids {
+					cmds[i] = []interface{}{4, id, 0} // Command LINK
+				}
+				newVals[name] = cmds
+			}
+		case TypeOne2many:
+			// Skip — O2M records are NOT copied by default (copy=false)
+			continue
+		default:
+			newVals[name] = val
+		}
+	}
+
+	// Append "(copy)" to rec_name field
+	recName := m.recName
+	if recName == "" {
+		recName = "name"
+	}
+	if nameVal, ok := newVals[recName].(string); ok {
+		newVals[recName] = nameVal + " (copy)"
+	}
+
+	// Apply user-provided defaults (override copied values)
+	if defaults != nil {
+		for k, v := range defaults {
+			newVals[k] = v
+		}
+	}
+
+	return rs.Create(newVals)
+}
+
 // Union returns the union of this recordset with others.
 // Mirrors: records | other_records
 func (rs *Recordset) Union(others ...*Recordset) *Recordset {

pkg/server/server.go

@@ -429,8 +429,10 @@ func (s *Server) dispatchORM(env *orm.Environment, params CallKWParams) (interfa
 			if len(params.Args) >= 3 {
 				if vals, ok := params.Args[1].(map[string]interface{}); ok {
 					if fieldNames, ok := params.Args[2].([]interface{}); ok {
+						var changed []string
 						for _, fn := range fieldNames {
 							fname, _ := fn.(string)
+							changed = append(changed, fname)
 							if handler, exists := model.OnchangeHandlers[fname]; exists {
 								updates := handler(env, vals)
 								for k, v := range updates {
@@ -438,6 +440,11 @@ func (s *Server) dispatchORM(env *orm.Environment, params CallKWParams) (interfa
 								}
 							}
 						}
+						// Run computed fields that depend on changed fields
+						computed := orm.RunOnchangeComputes(model, env, vals, changed)
+						for k, v := range computed {
+							defaults[k] = v
+						}
 					}
 				}
 			}
@@ -660,23 +667,9 @@ func (s *Server) dispatchORM(env *orm.Environment, params CallKWParams) (interfa
 		if len(ids) == 0 {
 			return nil, &RPCError{Code: -32000, Message: "No record to copy"}
 		}
-		// Read the original record
-		records, err := rs.Browse(ids[0]).Read(nil)
-		if err != nil || len(records) == 0 {
-			return nil, &RPCError{Code: -32000, Message: "Record not found"}
-		}
-		// Remove id and unique fields, create copy
-		vals := records[0]
-		delete(vals, "id")
-		delete(vals, "create_uid")
-		delete(vals, "write_uid")
-		delete(vals, "create_date")
-		delete(vals, "write_date")
-		// Append "(copy)" to name if it exists
-		if name, ok := vals["name"].(string); ok {
-			vals["name"] = name + " (copy)"
-		}
-		created, err := rs.Create(vals)
+		// Parse optional default overrides from args[1]
+		defaults := parseValuesAt(params.Args, 1)
+		created, err := rs.Browse(ids[0]).Copy(defaults)
 		if err != nil {
 			return nil, &RPCError{Code: -32000, Message: err.Error()}
 		}