Laravel jenssegers/laravel-mongodb belongsTo混合关联调用报错排查

跨SQL、MongoDB双存储创建Eloquent关联时，两个模型代码如下：

SQL端 Location 模型 #

<?php

namespace App\Models\Trend;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Jenssegers\Mongodb\Eloquent\HybridRelations;

class Location extends Model
{
    use HasFactory, HybridRelations;

    protected $table = 'trends';

    protected $fillable = [
        'woeid',
        'name',
    ];

    public function trends()
    {
        return $this->hasMany(Trend::class);
    }
}

MongoDB端 Trend 模型 #

<?php

namespace App\Models\Trend;

use App\Models\Scopes\AscendingOrderScope;
use App\Models\Team;
use App\Models\User;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Jenssegers\Mongodb\Eloquent\Model;

class Trend extends Model
{
    use HasFactory;

    protected $connection = 'mongodb';

    protected $collection = 'trends';

    protected $fillable = ['trends'];

    protected static function booted()
    {
        static::addGlobalScope(new AscendingOrderScope);
    }

    public function location()
    {
        return $this->belongsTo(Location::class);
    }
}

调用Trend模型的->location关联时抛出错误：

PHP Error:  Call to a member function prepare() on null in /home/fmk/Code/socmint/vendor/laravel/framework/src/Illuminate/Database/Connection.php on line 413

已确认的前置状态：

• MongoDB集合中location_id字段值对应存在的Location记录ID
• 已按文档在Location模型中引入HybridRelations trait
• 反向关联location->trends可正常运行

HybridRelations trait 必须在关联两端的模型中同时引入，不能仅在SQL端模型使用。
该扩展的混合关联逻辑需要两端模型都加载trait，才能正确识别跨库连接配置。缺少trait时，MongoDB模型执行belongsTo查询会错误调用Mongo连接不存在的SQLprepare方法，触发报错。

在Trend模型中引入并使用HybridRelations trait：

<?php

namespace App\Models\Trend;

use App\Models\Scopes\AscendingOrderScope;
use App\Models\Team;
use App\Models\User;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Jenssegers\Mongodb\Eloquent\Model;
use Jenssegers\Mongodb\Eloquent\HybridRelations;

class Trend extends Model
{
    use HasFactory, HybridRelations;

    protected $connection = 'mongodb';

    protected $collection = 'trends';

    protected $fillable = ['trends'];

    protected static function booted()
    {
        static::addGlobalScope(new AscendingOrderScope);
    }

    public function location()
    {
        return $this->belongsTo(Location::class);
    }
}

修改后关联即可正常运行。

内容的提问来源于stack exchange，提问作者FMK