DDC-729: When merging many to many entities back into the repository all associations are deleted on the next flush #898

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admin · 2026-01-22T12:54:37+01:00

admin commented

2026-01-22 12:54:37 +01:00

Originally created by @doctrinebot on GitHub (Jul 31, 2010).

Originally assigned to: @beberlei on GitHub.

Jira issue originally created by user ccapndave:

When merging a DETACHED entity into the repository with a ManyToMany association, the entries in the join table are deleted on the next flush.

Many Movies have many Artists:

class Movie {

    /*** @Id @Column(type="integer") @GeneratedValue(strategy="IDENTITY") **/
    public $id;

    /*** @Column(length=50, type="string") **/
    public $title;

    /**** 
     * @ManyToMany(targetEntity="Artist")
     */
    public $artists;

    public function **construct() {
        $this->artists = new ArrayCollection();
    }

}

class Artist {

    /*** @Id @Column(type="integer") @GeneratedValue(strategy="IDENTITY") **/
    public $id;

    /*** @Column(length=50, type="string") **/
    public $name;

    /*** @ManyToMany(targetEntity="Movie", mappedBy="artists") **/
    public $movies;

    public function **construct() {
        $this->movies = new ArrayCollection();
    }

}

Assume that the database contains:
Movie: id=1, title="Movie 1"
Artist: id=1, name="Artist 1"

and that there is a entry (1, 1) in movie_artist so that there is a many-many relationship between Movie 1 and Artist 1.

I then run the following code to merge the existing associations into the entity manager:

$m1 = new \vo\Movie();
$m1->id = 1;
$m1->title = "Movie 1";

$a1 = new \vo\Artist();
$a1->id = 1;
$a1->name = "Artist 1";

$m1->artists->add($a1); $a1->movies->add($m1);

$m1 = $em->merge($m1);
$m1->artists->set(0, $em->merge($a1));
$a1->movies->set(0, $em->merge($m1));

At this point $m1 should contains merged entities reflecting the same as what is in the database.

If I now run:

$em->flush()

the association is deleted from movie_artist and the SQL log shows DELETE FROM Movie_Artist WHERE Movie_id = '1' as having been run.

Debugging $m1 both before and after the flush shows the expected values, and $em->getUnitOfWork()->computeChangeSets() is empty before the flush.

Originally created by @doctrinebot on GitHub (Jul 31, 2010). Originally assigned to: @beberlei on GitHub. Jira issue originally created by user ccapndave: When merging a DETACHED entity into the repository with a ManyToMany association, the entries in the join table are deleted on the next flush. Many Movies have many Artists: ``` class Movie { /*** @Id @Column(type="integer") @GeneratedValue(strategy="IDENTITY") **/ public $id; /*** @Column(length=50, type="string") **/ public $title; /**** * @ManyToMany(targetEntity="Artist") */ public $artists; public function **construct() { $this->artists = new ArrayCollection(); } } ``` ``` class Artist { /*** @Id @Column(type="integer") @GeneratedValue(strategy="IDENTITY") **/ public $id; /*** @Column(length=50, type="string") **/ public $name; /*** @ManyToMany(targetEntity="Movie", mappedBy="artists") **/ public $movies; public function **construct() { $this->movies = new ArrayCollection(); } } ``` Assume that the database contains: Movie: id=1, title="Movie 1" Artist: id=1, name="Artist 1" and that there is a entry (1, 1) in movie_artist so that there is a many-many relationship between Movie 1 and Artist 1. I then run the following code to merge the existing associations into the entity manager: ``` $m1 = new \vo\Movie(); $m1->id = 1; $m1->title = "Movie 1"; $a1 = new \vo\Artist(); $a1->id = 1; $a1->name = "Artist 1"; $m1->artists->add($a1); $a1->movies->add($m1); $m1 = $em->merge($m1); $m1->artists->set(0, $em->merge($a1)); $a1->movies->set(0, $em->merge($m1)); ``` At this point $m1 should contains merged entities reflecting the same as what is in the database. If I now run: ``` $em->flush() ``` the association is deleted from movie_artist and the SQL log shows DELETE FROM Movie_Artist WHERE Movie_id = '1' as having been run. Debugging $m1 both before and after the flush shows the expected values, and $em->getUnitOfWork()->computeChangeSets() is empty before the flush.

admin added the Bug label 2026-01-22 12:54:37 +01:00

admin referenced this issue

2026-01-22 16:02:05 +01:00

[PR #898] [MERGED] Added note to STI #8870

admin referenced this issue

2026-01-22 16:02:05 +01:00

[PR #898] Added note to STI #8874

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