Use primary key instead of binding key in case of BelongsToMany association

[ravage84]

Belongs to many associations have a junction table or through model:

https://book.cakephp.org/4/en/orm/associations.html#belongstomany-associations

A field named like the binding key does not necessarily exist on the target table but only on the junction table.

This change is necessary to prevent the exception introduced by the backport of cakephp/cakephp#17340 to be thrown in such cases.

cakephp/collection@3897169#diff-81970ebd43ab052712b24c8315dfd428fea23a3dcea21316e27d9ce9a2551b83R596-R599

I encountered this after upgrading an application from CakePHP 4.4.x. to 4.5.x.

The reason why this has worked before 4.5 is mentioned at cakephp/cakephp#17340 (comment).

This change is likely also necessary for the CRUD branch for CakePHP 5.x.

[ravage84]

Alternatively, the code could look like this:

Suggested change

	if ($association instanceof Association\BelongsToMany) {
	return [
	'keyField' => $association->getPrimaryKey(),
	];
	}
	return [
	'keyField' => $association->getBindingKey(),
	];
	$keyField = $association->getBindingKey();
	if ($association instanceof Association\BelongsToMany) {
	$keyField = $association->getPrimaryKey();
	}
	return [
	'keyField' =>$keyField,
	];

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (39a7cff) 89.24% compared to head (537cd38) 90.14%.
Report is 29 commits behind head on master.

❗ Current head 537cd38 differs from pull request most recent head d4c42f9. Consider uploading reports for the commit d4c42f9 to get more accurate results

Files	Patch %	Lines
src/Listener/RelatedModelsListener.php	0.00%	5 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #711      +/-   ##
============================================
+ Coverage     89.24%   90.14%   +0.90%     
+ Complexity      381      370      -11     
============================================
  Files            36       36              
  Lines          1181     1157      -24     
============================================
- Hits           1054     1043      -11     
+ Misses          127      114      -13     

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[ADmad]

Test case required.

BTW the docs say it's the column of the "current" table, not junction table.

bindingKey: The name of the column in the current table, that will be used for matching the foreignKey. Defaults to the primary key.

P.S. The master branch is for CakePHP 5, I can backport it later.