feat: harden campaign delivery and editing

src/govoplan_campaign/backend/route_support.py

@@ -43,6 +43,12 @@ from govoplan_campaign.backend.sending.execution import (
 from govoplan_core.audit.logging import audit_from_principal
 from govoplan_core.auth import ApiPrincipal, has_scope
 from govoplan_core.core.access import CAPABILITY_ACCESS_DIRECTORY, AccessDirectory
+from govoplan_core.core.concurrency import (
+    ConcurrencyError,
+    MissingPreconditionError,
+    RevisionConflictError,
+    assert_revision_precondition,
+)
 from govoplan_core.core.runtime import get_registry
 
 
@@ -359,6 +365,9 @@ def _campaign_version_detail_response(
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)
         ) from exc
+    except RevisionConflictError:
+        session.rollback()
+        raise
     except Exception as exc:
         session.rollback()
         if validation_error_status is None:
@@ -375,44 +384,109 @@ def _update_campaign_version_detail_response(
     version_id: str,
     payload: CampaignVersionUpdateRequest,
     *,
+    if_match: str | None,
     autosave: bool,
     audit_action: str,
 ) -> CampaignVersionDetailResponse:
     _get_campaign_for_principal(session, campaign_id, principal, write=True)
     current_version = _get_version_for_tenant(session, version_id, principal.tenant_id)
+    if payload.base_revision is None:
+        error = MissingPreconditionError(
+            resource_type="campaign_version",
+            resource_id=version_id,
+        )
+        raise HTTPException(
+            status_code=status.HTTP_428_PRECONDITION_REQUIRED,
+            detail=error.as_dict(),
+        )
+    try:
+        assert_revision_precondition(
+            if_match,
+            resource_type="campaign_version",
+            resource_id=version_id,
+            submitted_base_revision=payload.base_revision,
+        )
+    except MissingPreconditionError as exc:
+        raise HTTPException(
+            status_code=status.HTTP_428_PRECONDITION_REQUIRED,
+            detail=exc.as_dict(),
+        ) from exc
+    except ConcurrencyError as exc:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail={
+                "code": "invalid_precondition",
+                "message": str(exc),
+            },
+        ) from exc
     if _recipient_sections_changed(current_version.raw_json, payload.campaign_json):
         _require_permission(principal, "campaigns:recipient:write")
     _require_mail_profile_use_if_needed(principal, payload.campaign_json)
-    return _campaign_version_detail_response(
-        session,
-        principal,
-        campaign_id,
-        lambda: update_campaign_version(
+    try:
+        return _campaign_version_detail_response(
             session,
-            tenant_id=principal.tenant_id,
-            campaign_id=campaign_id,
-            version_id=version_id,
-            raw_json=payload.campaign_json,
-            current_flow=payload.current_flow,
-            current_step=payload.current_step,
-            workflow_state=payload.workflow_state,
-            is_complete=payload.is_complete,
-            editor_state=payload.editor_state,
-            source_filename=payload.source_filename,
-            source_base_path=payload.source_base_path,
-            autosave=autosave,
-            migrate_legacy_mail_settings=payload.migrate_legacy_mail_settings,
-            commit=False,
-        ),
-        audit_action=audit_action,
-        details=lambda version: {
-            "campaign_id": campaign_id,
-            "current_flow": version.current_flow,
-            "current_step": version.current_step,
-            "legacy_mail_settings_migrated": payload.migrate_legacy_mail_settings,
-        },
-        validation_error_status=status.HTTP_422_UNPROCESSABLE_CONTENT,
-    )
+            principal,
+            campaign_id,
+            lambda: update_campaign_version(
+                session,
+                tenant_id=principal.tenant_id,
+                campaign_id=campaign_id,
+                version_id=version_id,
+                raw_json=payload.campaign_json,
+                current_flow=payload.current_flow,
+                current_step=payload.current_step,
+                workflow_state=payload.workflow_state,
+                is_complete=payload.is_complete,
+                editor_state=payload.editor_state,
+                source_filename=payload.source_filename,
+                source_base_path=payload.source_base_path,
+                autosave=autosave,
+                migrate_legacy_mail_settings=payload.migrate_legacy_mail_settings,
+                expected_revision=payload.base_revision,
+                commit=False,
+            ),
+            audit_action=audit_action,
+            details=lambda version: {
+                "campaign_id": campaign_id,
+                "current_flow": version.current_flow,
+                "current_step": version.current_step,
+                "base_revision": payload.base_revision,
+                "result_revision": version.edit_revision,
+                "reconciliation_kind": payload.reconciliation_kind,
+                "resolved_conflict_path_count": len(
+                    payload.resolved_conflict_paths
+                ),
+                "resolved_conflict_sections": sorted(
+                    {
+                        path.strip("/").split("/", 1)[0][:80]
+                        for path in payload.resolved_conflict_paths[:100]
+                        if path.strip("/")
+                    }
+                ),
+                "legacy_mail_settings_migrated": payload.migrate_legacy_mail_settings,
+            },
+            validation_error_status=status.HTTP_422_UNPROCESSABLE_CONTENT,
+        )
+    except RevisionConflictError as exc:
+        session.rollback()
+        audit_from_principal(
+            session,
+            principal,
+            action="campaign.version_conflict_detected",
+            object_type="campaign_version",
+            object_id=version_id,
+            details={
+                "campaign_id": campaign_id,
+                "submitted_base_revision": exc.submitted_base_revision,
+                "current_revision": exc.current_revision,
+                "retryable": True,
+            },
+            commit=True,
+        )
+        raise HTTPException(
+            status_code=status.HTTP_412_PRECONDITION_FAILED,
+            detail=exc.as_dict(),
+        ) from exc
 
 
 def _require_campaign_profile_use_if_needed(