Framework: Model::$withCount for polymorphic models + Eloquent\Builder::where(\Closure) triggers unexpected bound parameter mismatching

[mpyw]

• Laravel Version: 5.5.28

Description:

Model::$withCount for polymorphic models + Eloquent\Builder::where(\Closure) triggers unexpected bound parameter mismatching.

Related codes:

    /**
     * Add a basic where clause to the query.
     *
     * @param  string|array|\Closure  $column
     * @param  string  $operator
     * @param  mixed  $value
     * @param  string  $boolean
     * @return $this
     */
    public function where($column, $operator = null, $value = null, $boolean = 'and')
    {
        if ($column instanceof Closure) {
            $query = $this->model->newQueryWithoutScopes(); // <---

            $column($query);

            $this->query->addNestedWhereQuery($query->getQuery(), $boolean);
        } else {
            $this->query->where(...func_get_args());
        }

        return $this;
    }

    /**
     * Get a new query builder that doesn't have any global scopes.
     *
     * @return \Illuminate\Database\Eloquent\Builder|static
     */
    public function newQueryWithoutScopes()
    {
        $builder = $this->newEloquentBuilder($this->newBaseQueryBuilder());

        // Once we have the query builders, we will set the model instances so the
        // builder can easily access any information it may need from the model
        // while it is constructing and executing various queries against it.
        return $builder->setModel($this)
                    ->with($this->with)
                    ->withCount($this->withCount); // <---
    }

I think Eloquent\Builder::where(\Closure) expects Model::newQueryWithoutScopes() to return Eloquent\Builder exactly without bindings, but actually it may contain bindings for polymorphic relation: *able_type = ?

Steps To Reproduce:

The last two mismatching bound parameters "post", "post" trigger SQL error.

[staudenmeir]

This is a known issue: #23957

[mpyw]

@staudenmeir Should I always use Model::addGlobalScope() instead? However it has many different behaviors. For instance, Model::refresh() load attributes from Model::$withCount, not from Model::addGlobalScope().

[mpyw]

I never plan to use Model::$withCount for production use, but I'm using it for a temporary implementation until implementing counter caches.

[staudenmeir]

I don't know a good workaround for this problem. We are working on a solution: #24000

[mpyw]

@staudenmeir I'll appreciate for your great try. Thank you