U €Haèã@sLddlmZddlmZddd„ZeddƒZddd „Zdd d „Zd d„ZdS)é)Ú namedtuple)ÚRECURSIVE_RELATIONSHIP_CONSTANTNcCs‚t|tƒrr|tkr2|dks"|dkr*tdƒ‚||fSd|krV| dd¡\}}|| ¡fS|dkrftdƒ‚|| ¡fS|jj|jjfS)z¾ Turn a model class or model reference string and return a model tuple. app_label and model_name are used to resolve the scope of recursive and unscoped model relationship. NzMapp_label and model_name must be provided to resolve recursive relationships.Ú.ézCapp_label must be provided to resolve unscoped model relationships.) Ú isinstanceÚstrrÚ TypeErrorÚsplitÚlowerZ_metaÚ app_labelÚ model_name)Úmodelr r ©rúI/tmp/pip-unpacked-wheel-3jxiddxt/django/db/migrations/operations/utils.pyÚresolve_relations  ÿ ÿ rÚFieldReferencez to throughc CsÊ|j}|sdSd}d}t|jf|žŽ|krlt|ddƒ}|dksd|dksdd|kr\|dksd|jsd||krl||f}t|ddƒ} | r´t| f|žŽ|kr´|j} |dks¬| dks¬|| kr´|| f}|sÀ|sÀdSt||ƒS)at Return either False or a FieldReference if `field` references provided context. False positives can be returned if `reference_field_name` is provided without `reference_field` because of the introspection limitation it incurs. This should not be an issue when this function is used to determine whether or not an optimization can take place. FNÚ to_fieldsÚthrough)Ú remote_fieldrr ÚgetattrZ primary_keyÚthrough_fieldsr) Ú model_tupleÚfieldZreference_model_tupleZreference_field_nameZreference_fieldrZ references_toZreferences_throughrrrrrrÚfield_references$sB ÿýûûûù  ÿýûrrccsP|j ¡D]@\}}|j ¡D],\}}t|||f|žŽ}|r||||fVqq dS)zÍ Generator of (model_state, name, field, reference) referencing provided context. If field_tuple is provided only references to this particular field of model_tuple will be generated. N)ÚmodelsÚitemsÚfieldsr)ÚstaterÚ field_tupleZstate_model_tupleZ model_stateÚnamerÚ referencerrrÚget_referencesUs r!cCstt|||ƒdƒdk S)z?Return whether `field_tuple` is referenced by any state models.N)Únextr!)rrrrrrÚfield_is_referenceddsr#)NN)NN)r) Ú collectionsrZdjango.db.models.fields.relatedrrrrr!r#rrrrÚs    û 1