paperwork: Convert CertificationVersion is_current/latest to annotations

Pretty sigificantly improves performance of views that use it

paperwork/admin.py

@@ -37,6 +37,14 @@ class CertificationVersionInline(admin.TabularInline):
         "is_current",
     )
 
+    @admin.display(description="Latest", boolean=True)
+    def is_latest(self, obj):
+        return obj.is_latest
+
+    @admin.display(description="Current", boolean=True)
+    def is_current(self, obj):
+        return obj.is_current
+
 
 @admin.register(CertificationDefinition)
 class CertificationDefinitionAdmin(admin.ModelAdmin):
@@ -64,6 +72,10 @@ class CertificationAdmin(admin.ModelAdmin):
     autocomplete_fields = ["member"]
     exclude = ["shop_lead_notified"]
 
+    def get_queryset(self, request):
+        qs = super().get_queryset(request)
+        return qs.prefetch_related("certification_version__definition__department")
+
     @admin.display(
         description="Certification Name",
         ordering="certification_version__definition__certification_name",
@@ -87,8 +99,8 @@ class CertificationAdmin(admin.ModelAdmin):
         return obj.certification_version.semantic_version()
 
     @admin.display(description="Current", boolean=True)
-    def certification_version__is_current(self, obj):
+    def is_current(self, obj):
-        return obj.certification_version.is_current()
+        return obj.certification_version.is_current
 
     @admin.display(
         description="Department",
@@ -101,7 +113,7 @@ class CertificationAdmin(admin.ModelAdmin):
         "certification_name",
         "name",
         "certification_semantic_version",
-        "certification_version__is_current",
+        "is_current",
         "certification_department",
         "date",
         "shop_lead_notified",

paperwork/models.py

@@ -2,6 +2,7 @@ import re
 
 from semver import VersionInfo
 from django.db import models
+from django.db.models import ExpressionWrapper, OuterRef, Q, Subquery
 from django.core.validators import RegexValidator
 
 from membershipworks.models import Member, Flag as MembershipWorksFlag
@@ -91,12 +92,29 @@ class CertificationDefinition(models.Model):
         ordering = ("certification_name", "department")
 
     def latest_version(self) -> "CertificationVersion":
-        all_versions = CertificationVersion.objects.filter(definition=self)
+        return self.certificationversion_set.latest()
 
-        return max(all_versions, key=lambda version: version.semantic_version())
+
+class CertificationVersionManager(models.Manager):
+    def get_queryset(self):
+        qs = super().get_queryset()
+        latest = qs.filter(definition__pk=OuterRef("definition__pk"))
+        return qs.annotate(
+            is_latest=ExpressionWrapper(
+                Q(pk=Subquery(latest.values("pk")[:1])),
+                output_field=models.BooleanField(),
+            ),
+            # TODO: should do a more correct comparison than just major version
+            is_current=ExpressionWrapper(
+                Q(major=Subquery(latest.values("major")[:1])),
+                output_field=models.BooleanField(),
+            ),
+        )
 
 
 class CertificationVersion(models.Model):
+    objects = CertificationVersionManager()
+
     definition = models.ForeignKey(
         CertificationDefinition, on_delete=models.PROTECT, db_column="Certification"
     )
@@ -117,6 +135,8 @@ class CertificationVersion(models.Model):
             )
         ]
         ordering = ("major", "minor", "patch", "prerelease", "approval_date")
+        get_latest_by = ("major", "minor", "patch", "prerelease", "approval_date")
+        base_manager_name = "objects"
 
     def semantic_version(self) -> VersionInfo:
         return VersionInfo(
@@ -127,18 +147,6 @@ class CertificationVersion(models.Model):
             self.approval_date.isoformat() if self.approval_date is not None else None,
         )
 
-    def is_latest(self) -> bool:
-        return self.definition.latest_version() == self
-
-    is_latest.boolean = True
-
-    def is_current(self) -> bool:
-        """Returns true if this version compatible with the latest version"""
-        # TODO: should do a more correct comparison than just major version
-        return self.definition.latest_version().major == self.major
-
-    is_current.boolean = True
-
 
 class Certification(models.Model):
     number = models.AutoField(db_column="Number", primary_key=True)