解决Odoo中One2many组件新建记录时的ValueError错误

我在product.template模型中添加了一个简单的One2many字段，并在product.template表单视图中配置了one2many组件。组件能正常显示，但点击“Add a line”按钮新建记录时，触发错误：

ValueError: Invalid field 'product_variant_count' on model '_unknown'

奇怪的是，我的代码中并未使用错误信息里提到的product_variant_count字段。环境为Odoo-14，Python 3.9。

相关代码 #

1. product.template.substitute模型 #

class ProductTemplateSubstitute(models.Model):
    _name = "product.template.substitute"
    _description = "Product Substitute"
    _rec_name = "manufacturer_part_number"

    manufacturer_part_number = fields.Char(string="Manufacturer Part Number", required=True)
    product_id = fields.Many2one(string="Product", required=True)

    _sql_constraints = [
        (
            "unique_manufacturer_part_number",
            "unique (manufacturer_part_number)",
            "Manufacturer part number already exists!",
        )
    ]

2. product.template模型继承 #

class ProductTemplateInherited(models.Model):
    _inherit = "product.template"

    product_substitute_ids = fields.One2many(
        string="Product Substitutes", comodel_name="product.template.substitute", inverse_name="product_id"
    )

3. product.template视图配置 #

<odoo>
    <record id="product_template_form_view" model="ir.ui.view">
        <field name="name">product.template.form.view.inherit.vendor.eshop.connector</field>
        <field name="model">product.template</field>
        <field name="inherit_id" ref="product.product_template_form_view"/>
        <field name="arch" type="xml">
            <group name="bill" position="after">
                <group name="product_substitutes" string="Substitutes">
                    <field name="product_substitute_ids" widget="one2many" nolabel="1">
                    <tree editable="bottom">
                        <field name="manufacturer_part_number"/>
                    </tree>
                </field>
                </group>
            </group>
        </field>
    </record>
</odoo>

错误根源是product.template.substitute模型中的product_id字段（Many2one类型）未指定comodel_name参数，导致Odoo无法识别关联的目标模型，进而触发了非预期的字段错误。修正后的代码如下：

# 错误写法
product_id = fields.Many2one(string="Product", required=True)
# 正确写法
product_id = fields.Many2one(string="Product", comodel_name="product.template", required=True)

内容的提问来源于stack exchange，提问作者xixo222