Migrations need to be in two files to work

Good news: they run now

bookwyrm/migrations/0151_auto_20220703_1842.py

@@ -1,7 +1,7 @@
 # Generated by Django 3.2.13 on 2022-07-03 18:42
 
 from django.db import migrations, models
-from django.db.models import OuterRef, Subquery, F, Q
+from django.db.models import OuterRef, Subquery, Q
 
 
 # TODO: test this
@@ -23,12 +23,12 @@ def set_read_status(apps, schema_editor):
 
     # if it has finished date, it's read. strictly speaking this is unnecessary if all
     # is well because this is the default value.
-    readthrough_model.objects.using(db_alias).filter(
+    readthrough_model.objects.using(db_alias).filter(finish_date__isnull=False).update(
-        finished_date__isnull=False
+        read_status="read"
-    ).update(read_status="read")
+    )
 
     # if it has a stopped date, it's stopped
-    readthrough_model.objects.using(db_alias).filter(stooped_date__isnull=False).update(
+    readthrough_model.objects.using(db_alias).filter(stopped_date__isnull=False).update(
         read_status="stopped-reading"
     )
 
@@ -41,7 +41,7 @@ def set_read_status(apps, schema_editor):
     statuses = readthrough_model.objects.using(db_alias).filter(
         user=OuterRef("shelf__user"),
         book=OuterRef("book"),
-        status=OuterRef("shelf__identifier"),
+        read_status=OuterRef("shelf__identifier"),
     )
     statusesless_shelfbooks = (
         shelfbook_model.objects.using(db_alias)
@@ -49,8 +49,9 @@ def set_read_status(apps, schema_editor):
             shelf__editable=False,  # on a functional shelf
         )
         .annotate(  # check if this shelbook has an associated status
-            status_exists=Subquery(statuses.exists())
+            status_exists=Subquery(statuses.values("id")[:1])
         )
+        .filter(status_exists__isnull=True)
     )
 
     # create new statuses
@@ -61,30 +62,20 @@ def set_read_status(apps, schema_editor):
                 book=sb.book,
                 user=sb.shelf.user,
             )
-            for sb in statusesless_shelfbooks.objects.all()
+            for sb in statusesless_shelfbooks.all()
         ]
     )
 
 
-def merge_finish_stopped_dates(apps, schema_editor):
+def reverse_read_status_step(apps, schema_editor):
-    """Combine the finished and stopped dates fields"""
+    """Infer the correct reading status from the existing readthrough data"""
     db_alias = schema_editor.connection.alias
     readthrough_model = apps.get_model("bookwyrm", "ReadThrough")
-    readthrough_model.objects.using(db_alias).filter(stopped_date__isnull=False).update(
+    readthrough_model.objects.using(db_alias).filter(read_status="reading").update(
-        finish_date=F("stopped_date")
+        is_active=True
     )
 
 
-def unmerge_finish_stopped_dates(apps, schema_editor):
-    """Combine the finished and stopped dates fields"""
-    db_alias = schema_editor.connection.alias
-    readthrough_model = apps.get_model("bookwyrm", "ReadThrough")
-    readthrough_model.objects.using(db_alias).filter(
-        read_status="stopped-reading",
-        finish_date__isnull=False,
-    ).update(stopped_date=F("finish_date"))
-
-
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -106,13 +97,5 @@ class Migration(migrations.Migration):
                 max_length=20,
             ),
         ),
-        migrations.RemoveField(
+        migrations.RunPython(set_read_status, reverse_read_status_step),
-            model_name="readthrough",
-            name="is_active",
-        ),
-        migrations.RunPython(merge_finish_stopped_dates, unmerge_finish_stopped_dates),
-        migrations.RemoveField(
-            model_name="readthrough",
-            name="stopped_date",
-        ),
     ]

bookwyrm/migrations/0152_auto_20220704_0135.py

@@ -0,0 +1,42 @@
+# Generated by Django 3.2.13 on 2022-07-04 01:35
+
+from django.db import migrations
+from django.db.models import F
+
+
+def merge_finish_stopped_dates(apps, schema_editor):
+    """Combine the finished and stopped dates fields"""
+    db_alias = schema_editor.connection.alias
+    readthrough_model = apps.get_model("bookwyrm", "ReadThrough")
+    readthrough_model.objects.using(db_alias).filter(stopped_date__isnull=False).update(
+        finish_date=F("stopped_date")
+    )
+
+
+def unmerge_finish_stopped_dates(apps, schema_editor):
+    """Combine the finished and stopped dates fields"""
+    db_alias = schema_editor.connection.alias
+    readthrough_model = apps.get_model("bookwyrm", "ReadThrough")
+    readthrough_model.objects.using(db_alias).filter(
+        read_status="stopped-reading",
+        finish_date__isnull=False,
+    ).update(stopped_date=F("finish_date"))
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("bookwyrm", "0151_auto_20220703_1842"),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name="readthrough",
+            name="is_active",
+        ),
+        migrations.RunPython(merge_finish_stopped_dates, unmerge_finish_stopped_dates),
+        migrations.RemoveField(
+            model_name="readthrough",
+            name="stopped_date",
+        ),
+    ]