The mappings App\Entity\Composant#fournisseurs and App\Entity\Fournisseur#composants are inconsistent with each other.
The field App\Entity\Composant#qt is on the owning side of a bi-directional relationship, but the specified inversedBy association on the target-entity App\Entity\Qt#composants does not contain the required 'mappedBy="qt"' attribute.
If association App\Entity\Composant#qt is many-to-one, then the inversed side App\Entity\Qt#composants has to be one-to-many.
The association App\Entity\Composant#commande refers to the inverse side field App\Entity\Commande#countCommande which does not exist.