feat: harden campaign delivery and editing

src/govoplan_campaign/backend/persistence/versions.py

@@ -7,7 +7,12 @@ from typing import Any
 from uuid import uuid4
 
 from sqlalchemy.orm import Session
+from sqlalchemy.orm.exc import StaleDataError
 
+from govoplan_core.core.concurrency import (
+    RevisionConflictError,
+    strong_resource_etag,
+)
 from govoplan_campaign.backend.db.models import (
     Campaign,
     CampaignIssue,
@@ -720,12 +725,31 @@ def update_campaign_version(
     source_base_path: str | None = None,
     autosave: bool = False,
     migrate_legacy_mail_settings: bool = False,
+    expected_revision: int | None = None,
     commit: bool = True,
 ) -> CampaignVersion:
     _assert_update_paths_safe(raw_json, source_filename=source_filename, source_base_path=source_base_path)
     version = get_campaign_version_for_tenant(session, tenant_id=tenant_id, campaign_id=campaign_id, version_id=version_id)
     campaign = _require_campaign(session, campaign_id)
     ensure_current_working_version(campaign, version, action="edit")
+    if (
+        expected_revision is not None
+        and version.edit_revision != int(expected_revision)
+    ):
+        raise RevisionConflictError(
+            resource_type="campaign_version",
+            resource_id=version.id,
+            current_revision=version.edit_revision,
+            submitted_base_revision=int(expected_revision),
+            refresh_path=(
+                f"/api/v1/campaigns/{campaign.id}/versions/{version.id}"
+            ),
+            current_etag=strong_resource_etag(
+                "campaign_version",
+                version.id,
+                version.edit_revision,
+            ),
+        )
 
     if is_version_locked(version):
         raise LockedCampaignVersionError(
@@ -761,7 +785,42 @@ def update_campaign_version(
     # Changes invalidate previous build and validation summaries.
     if raw_json is not None:
         _invalidate_version_content(session, campaign=campaign, version=version)
-    _persist_updated_version(session, campaign=campaign, version=version, commit=commit)
+    try:
+        _persist_updated_version(
+            session,
+            campaign=campaign,
+            version=version,
+            commit=commit,
+        )
+    except StaleDataError as exc:
+        session.rollback()
+        current_revision = (
+            session.query(CampaignVersion.edit_revision)
+            .filter(CampaignVersion.id == version_id)
+            .scalar()
+        )
+        if current_revision is None:
+            raise CampaignPersistenceError(
+                f"Campaign version not found: {version_id}"
+            ) from exc
+        raise RevisionConflictError(
+            resource_type="campaign_version",
+            resource_id=version_id,
+            current_revision=int(current_revision),
+            submitted_base_revision=int(
+                expected_revision
+                if expected_revision is not None
+                else version.edit_revision
+            ),
+            refresh_path=(
+                f"/api/v1/campaigns/{campaign_id}/versions/{version_id}"
+            ),
+            current_etag=strong_resource_etag(
+                "campaign_version",
+                version_id,
+                int(current_revision),
+            ),
+        ) from exc
     return version