models: Use more sensitive on_delete clauses for foreign keys

itou/approvals/models.py

@@ -484,7 +484,7 @@ class Approval(PENotificationMixin, CommonApprovalMixin):
     user = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         verbose_name="demandeur d'emploi",
-        on_delete=models.CASCADE,
+        on_delete=models.PROTECT,  # 2-step deletion, first the Approval to create a CancelledApproval then the User
         related_name="approvals",
     )
     created_by = models.ForeignKey(
@@ -507,7 +507,7 @@ class Approval(PENotificationMixin, CommonApprovalMixin):
         verbose_name="diagnostic d'éligibilité",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # To not mess with the `approval_eligibility_diagnosis` constraint
     )
 
     # 2023-08-17: An experiment to add a denormalized field “last_suspension_ended_at” did not exhibit large
@@ -1083,7 +1083,7 @@ def displayed_choices_for_siae(siae):
         settings.AUTH_USER_MODEL,
         verbose_name="créé par",
         null=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability
         related_name="approvals_suspended_set",
     )
     updated_at = models.DateTimeField(verbose_name="date de modification", auto_now=True)
@@ -1092,7 +1092,7 @@ def displayed_choices_for_siae(siae):
         verbose_name="mis à jour par",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability, the dates can be edited
     )
 
     objects = SuspensionQuerySet.as_manager()
@@ -1336,14 +1336,14 @@ class CommonProlongation(models.Model):
         settings.AUTH_USER_MODEL,
         verbose_name="déclarée par",
         null=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability
         related_name="%(class)ss_declared",
     )
     declared_by_siae = models.ForeignKey(
         "companies.Company",
         verbose_name="SIAE du déclarant",
         null=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability, people's organization can change
     )
 
     # It is assumed that an authorized prescriber has validated the prolongation beforehand.
@@ -1352,7 +1352,7 @@ class CommonProlongation(models.Model):
         verbose_name="prescripteur habilité qui a autorisé cette prolongation",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability
         related_name="%(class)ss_validated",
     )
 
@@ -1361,7 +1361,7 @@ class CommonProlongation(models.Model):
         verbose_name="organisation du prescripteur habilité",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability, people's organization can change
     )
 
     # `created_by` can be different from `declared_by` when created in admin.
@@ -1511,7 +1511,7 @@ class ProlongationRequest(CommonProlongation):
     processed_by = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         verbose_name="traité par",
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # For traceability and accountability
         related_name="%(class)s_processed",
         null=True,
         blank=True,

itou/common_apps/organizations/models.py

@@ -192,7 +192,7 @@ class MembershipAbstract(models.Model):
         settings.AUTH_USER_MODEL,
         related_name="updated_membershipmodel_set",
         null=True,
-        on_delete=models.CASCADE,
+        on_delete=models.SET_NULL,
         verbose_name="mis à jour par",
     )
 

itou/companies/models.py

@@ -486,7 +486,7 @@ class CompanyMembership(MembershipAbstract):
         settings.AUTH_USER_MODEL,
         related_name="updated_companymembership_set",
         null=True,
-        on_delete=models.CASCADE,
+        on_delete=models.SET_NULL,
         verbose_name="mis à jour par",
     )
     notifications = models.JSONField(verbose_name="notifications", default=dict, blank=True)
@@ -563,7 +563,7 @@ class JobDescription(models.Model):
     # Max number or workable hours per week in France (Code du Travail)
     MAX_WORKED_HOURS_PER_WEEK = 48
 
-    appellation = models.ForeignKey("jobs.Appellation", on_delete=models.CASCADE)
+    appellation = models.ForeignKey("jobs.Appellation", on_delete=models.RESTRICT)
     company = models.ForeignKey(Company, on_delete=models.CASCADE, related_name="job_description_through")
     created_at = models.DateTimeField(verbose_name="date de création", default=timezone.now)
     updated_at = models.DateTimeField(verbose_name="date de modification", auto_now=True, db_index=True)
@@ -581,7 +581,7 @@ class JobDescription(models.Model):
     )
     location = models.ForeignKey(
         "cities.City",
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,
         null=True,
         blank=True,
         verbose_name="localisation du poste",
@@ -808,7 +808,7 @@ class SiaeConvention(models.Model):
         related_name="reactivated_siae_convention_set",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # Only staff can update it, and we shouldn't delete one of those accounts
     )
     reactivated_at = models.DateTimeField(verbose_name="date de réactivation manuelle", blank=True, null=True)
 

itou/eligibility/models/geiq.py

@@ -235,7 +235,7 @@ class GEIQAdministrativeCriteria(AbstractAdministrativeCriteria):
         verbose_name="critère parent",
         blank=True,
         null=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # Prevent promoting a criteria form child to parent
     )
     # Some criteria do not belong to an annex or a level
     annex = models.CharField(
@@ -289,7 +289,7 @@ class GEIQSelectedAdministrativeCriteria(models.Model):
     )
     administrative_criteria = models.ForeignKey(
         GEIQAdministrativeCriteria,
-        on_delete=models.CASCADE,
+        on_delete=models.RESTRICT,
         related_name="administrative_criteria_through",
     )
     created_at = models.DateTimeField(verbose_name="date de création", default=timezone.now)

itou/eligibility/models/iae.py

@@ -276,7 +276,7 @@ class SelectedAdministrativeCriteria(models.Model):
     eligibility_diagnosis = models.ForeignKey(EligibilityDiagnosis, on_delete=models.CASCADE)
     administrative_criteria = models.ForeignKey(
         AdministrativeCriteria,
-        on_delete=models.CASCADE,
+        on_delete=models.RESTRICT,
         related_name="administrative_criteria_through",
     )
     created_at = models.DateTimeField(verbose_name="date de création", default=timezone.now)

itou/employee_record/models.py

@@ -177,7 +177,7 @@ class EmployeeRecord(ASPExchangeInformation):
     # - Approval
     job_application = models.ForeignKey(
         "job_applications.jobapplication",
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,
         null=True,
         verbose_name="candidature / embauche",
         related_name="employee_record",

itou/institutions/models.py

@@ -43,7 +43,7 @@ class InstitutionMembership(MembershipAbstract):
         settings.AUTH_USER_MODEL,
         related_name="updated_institutionmembership_set",
         null=True,
-        on_delete=models.CASCADE,
+        on_delete=models.SET_NULL,
         verbose_name="mis à jour par",
     )
 

itou/job_applications/models.py

@@ -467,7 +467,7 @@ class JobApplication(xwf_models.WorkflowEnabled, models.Model):
     job_seeker = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         verbose_name="demandeur d'emploi",
-        on_delete=models.CASCADE,
+        on_delete=models.RESTRICT,  # This object is central to us and the SIAE
         related_name="job_applications",
     )
 
@@ -505,7 +505,7 @@ class JobApplication(xwf_models.WorkflowEnabled, models.Model):
     sender = models.ForeignKey(
         settings.AUTH_USER_MODEL,
         verbose_name="utilisateur émetteur",
-        on_delete=models.SET_NULL,
+        on_delete=models.SET_NULL,  # FIXME: Do we need traceability and accountability?
         null=True,
         blank=True,
         related_name="job_applications_sent",
@@ -529,7 +529,7 @@ class JobApplication(xwf_models.WorkflowEnabled, models.Model):
         verbose_name="organisation du prescripteur émettrice",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.SET_NULL,  # FIXME: Do we need traceability and accountability?
     )
 
     to_company = models.ForeignKey(
@@ -549,7 +549,7 @@ class JobApplication(xwf_models.WorkflowEnabled, models.Model):
         verbose_name="poste retenu",
         blank=True,
         null=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.SET_NULL,  # FIXME: Maybe RESTRICT because its value should'nt changes, also exposed in API
         related_name="hired_job_applications",
     )
 
@@ -1230,7 +1230,9 @@ class JobApplicationTransitionLog(xwf_models.BaseTransitionLog):
     MODIFIED_OBJECT_FIELD = "job_application"
     EXTRA_LOG_ATTRIBUTES = (("user", "user", None),)
     job_application = models.ForeignKey(JobApplication, related_name="logs", on_delete=models.CASCADE)
-    user = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL)
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL
+    )  # FIXME: Do we need traceability and accountability?
 
     class Meta:
         verbose_name = "log des transitions de la candidature"

itou/prescribers/models.py

@@ -170,7 +170,7 @@ class PrescriberOrganization(AddressMixin, OrganizationAbstract):
         related_name="authorization_status_set",
         null=True,
         blank=True,
-        on_delete=models.SET_NULL,
+        on_delete=models.RESTRICT,  # Only staff can update it, and we shouldn't delete one of those accounts
     )
 
     objects = PrescriberOrganizationManager.from_queryset(PrescriberOrganizationQuerySet)()
@@ -333,7 +333,7 @@ class PrescriberMembership(MembershipAbstract):
         settings.AUTH_USER_MODEL,
         related_name="updated_prescribermembership_set",
         null=True,
-        on_delete=models.CASCADE,
+        on_delete=models.SET_NULL,
         verbose_name="mis à jour par",
     )
 

itou/siae_evaluations/models.py

@@ -181,7 +181,7 @@ class EvaluationCampaign(models.Model):
 
     institution = models.ForeignKey(
         "institutions.Institution",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: Seems dangerous to allow campaign deletion on institution deletion
         related_name="evaluation_campaigns",
         verbose_name="DDETS IAE responsable du contrôle",
         validators=[validate_institution],
@@ -445,7 +445,7 @@ class EvaluatedSiae(models.Model):
     siae = models.ForeignKey(
         "companies.Company",
         verbose_name="SIAE",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: RESTRICT because CaP is an auditability tool?
         related_name="evaluated_siaes",
     )
     # In “phase amiable” until documents have been reviewed.
@@ -635,14 +635,14 @@ class EvaluatedJobApplication(models.Model):
     job_application = models.ForeignKey(
         "job_applications.JobApplication",
         verbose_name="candidature",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: RESTRICT because CaP is an auditability tool?
         related_name="evaluated_job_applications",
     )
 
     evaluated_siae = models.ForeignKey(
         EvaluatedSiae,
         verbose_name="SIAE évaluée",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: RESTRICT because CaP is an auditability tool?
         related_name="evaluated_job_applications",
     )
     labor_inspector_explanation = models.TextField(verbose_name="commentaires de l'inspecteur du travail", blank=True)
@@ -759,18 +759,20 @@ class EvaluatedAdministrativeCriteria(models.Model):
     administrative_criteria = models.ForeignKey(
         "eligibility.AdministrativeCriteria",
         verbose_name="critère administratif",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: RESTRICT because CaP is an auditability tool?
         related_name="evaluated_administrative_criteria",
     )
 
     evaluated_job_application = models.ForeignKey(
         EvaluatedJobApplication,
         verbose_name="candidature évaluée",
-        on_delete=models.CASCADE,
+        on_delete=models.CASCADE,  # FIXME: RESTRICT because CaP is an auditability tool?
         related_name="evaluated_administrative_criteria",
     )
 
-    proof = models.ForeignKey("files.File", on_delete=models.CASCADE, blank=True, null=True)
+    proof = models.ForeignKey(
+        "files.File", on_delete=models.CASCADE, blank=True, null=True
+    )  # FIXME: RESTRICT because CaP is an auditability tool?
     uploaded_at = models.DateTimeField(verbose_name="téléversé le", blank=True, null=True)
     submitted_at = models.DateTimeField(verbose_name="transmis le", blank=True, null=True)
     review_state = models.CharField(

itou/users/models.py

@@ -196,7 +196,7 @@ class User(AbstractUser, AddressMixin):
     created_by = models.ForeignKey(
         "self",
         verbose_name="créé par",
-        on_delete=models.SET_NULL,
+        on_delete=models.SET_NULL,  # FIXME: Do we need traceability and accountability?
         null=True,
         blank=True,
     )