mirror of https://github.com/zulip/zulip.git
54 lines
2.1 KiB
Python
54 lines
2.1 KiB
Python
# Generated by Django 1.10.5 on 2017-04-13 22:12
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from django.db import migrations
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from django.db.backends.postgresql.schema import DatabaseSchemaEditor
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from django.db.migrations.state import StateApps
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from django.db.models import Count
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def fix_duplicate_attachments(apps: StateApps, schema_editor: DatabaseSchemaEditor) -> None:
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"""Migration 0041 had a bug, where if multiple messages referenced the
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same attachment, rather than creating a single attachment object
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for all of them, we would incorrectly create one for each message.
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This results in exceptions looking up the Attachment object
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corresponding to a file that was used in multiple messages that
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predate migration 0041.
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This migration fixes this by removing the duplicates, moving their
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messages onto a single canonical Attachment object (per path_id).
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"""
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Attachment = apps.get_model("zerver", "Attachment")
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# Loop through all groups of Attachment objects with the same `path_id`
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for group in (
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Attachment.objects.values("path_id")
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.annotate(Count("id"))
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.order_by()
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.filter(id__count__gt=1)
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):
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# Sort by the minimum message ID, to find the first attachment
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attachments = sorted(
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Attachment.objects.filter(path_id=group["path_id"]).order_by("id"),
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key=lambda x: min(x.messages.all().values_list("id")[0]),
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)
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surviving = attachments[0]
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to_cleanup = attachments[1:]
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for a in to_cleanup:
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# For each duplicate attachment, we transfer its messages
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# to the canonical attachment object for that path, and
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# then delete the original attachment.
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for msg in a.messages.all():
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surviving.messages.add(msg)
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surviving.is_realm_public = surviving.is_realm_public or a.is_realm_public
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surviving.save()
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a.delete()
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class Migration(migrations.Migration):
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dependencies = [
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("zerver", "0073_custom_profile_fields"),
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]
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operations = [
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migrations.RunPython(fix_duplicate_attachments, elidable=True),
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]
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