Issue 460: Set cascade delete pragma on connect.

- add test to ensure stray book stats are deleted
- data cleanup migration (one-time only)
- remove LanguageRepo.delete, deletes now cascade correctly

Author: jzohrab

lute/app_factory.py

@@ -314,6 +314,7 @@ def _create_app(app_config, extra_config):
     @listens_for(Pool, "connect")
     def _pragmas_on_connect(dbapi_con, con_record):  # pylint: disable=unused-argument
         dbapi_con.execute("pragma recursive_triggers = on;")
+        dbapi_con.execute("pragma foreign_keys = on;")
 
     with app.app_context():
         db.create_all()

lute/db/schema/migrations/20241221_clean_up_missing_relationships.sql

@@ -0,0 +1,25 @@
+-- Clean up bad data, where relationships are invalid.
+--
+-- Per issue 460, the pragma foreign_keys was not ON, so it's possible
+-- (though unlikely) that some data in the db is bad/unreachable.
+--
+-- This is being done as a one-time fix, rather than as a repeatable
+-- migration, as it would be very annoying if the data model changed
+-- and I forgot to update the script!!
+
+DELETE FROM languagedicts WHERE LdLgID NOT IN (SELECT LgID FROM languages);
+DELETE FROM wordsread WHERE WrLgID NOT IN (SELECT LgID FROM languages);
+
+DELETE FROM books WHERE BkLgID NOT IN (SELECT LgID FROM languages);
+DELETE FROM bookstats WHERE BkID NOT IN (SELECT BkID FROM books);
+DELETE FROM booktags WHERE BtBkID NOT IN (SELECT BkID FROM books) OR BtT2ID NOT IN (SELECT T2ID FROM tags2);
+
+DELETE FROM texts WHERE TxBkID NOT IN (SELECT BkID FROM books);
+DELETE FROM textbookmarks WHERE TbTxID NOT IN (SELECT TxID FROM texts);
+DELETE FROM sentences WHERE SeTxID NOT IN (SELECT TxID FROM texts);
+DELETE FROM wordsread WHERE WrTxID IS NOT NULL AND WrTxID NOT IN (SELECT TxID FROM texts);
+
+DELETE FROM wordtags WHERE WtWoID NOT IN (SELECT WoID FROM words) OR WtTgID NOT IN (SELECT TgID FROM tags);
+DELETE FROM wordimages WHERE WiWoID NOT IN (SELECT WoID FROM words);
+DELETE FROM wordflashmessages WHERE WfWoID NOT IN (SELECT WoID FROM words);
+DELETE FROM wordparents WHERE WpWoID NOT IN (SELECT WoID FROM words) OR WpParentWoID NOT IN (SELECT WoID FROM words);

lute/language/routes.py

@@ -6,7 +6,7 @@
 from sqlalchemy.exc import IntegrityError
 from flask import Blueprint, current_app, render_template, redirect, url_for, flash
 from lute.models.language import Language
-from lute.models.repositories import LanguageRepository, UserSettingRepository
+from lute.models.repositories import UserSettingRepository
 from lute.language.service import Service
 from lute.language.forms import LanguageForm
 from lute.db import db
@@ -156,8 +156,8 @@ def delete(langid):
     language = db.session.get(Language, langid)
     if not language:
         flash(f"Language {langid} not found")
-    r = LanguageRepository(db.session)
-    r.delete(language)
+    db.session.delete(language)
+    db.session.commit()
     return redirect(url_for("language.index"))
 
 

lute/models/repositories.py

@@ -141,29 +141,6 @@ def find_by_name(self, name):
             .first()
         )
 
-    def delete(self, language):
-        """
-        Hacky method to delete language and all terms, books, and dicts
-        associated with it.
-
-        There is _certainly_ a better way to do this using
-        Sqlalchemy relationships and cascade deletes, but I
-        was running into problems with it (things not cascading,
-        or warnings ("SAWarning: Object of type <Term> not in
-        session, add operation along 'Language.terms' will not
-        proceed") during test runs.  It would be nice to have
-        a "correct" mapping, but this is good enough for now.
-
-        TODO zzfuture fix: fix Language-Book and -Term mappings.
-        """
-        sqls = [
-            "pragma foreign_keys = ON",
-            f"delete from languages where LgID = {language.id}",
-        ]
-        for s in sqls:
-            self.session.execute(sqltext(s))
-        self.session.commit()
-
     def all_dictionaries(self):
         "All dictionaries for all languages."
         lang_dicts = {}

tests/orm/test_Book.py

@@ -6,6 +6,7 @@
 import pytest
 from lute.models.book import Book, BookTag, TextBookmark, BookStats
 from lute.read.service import Service
+from lute.book.stats import Service as BookStatsService
 from lute.db import db
 from tests.dbasserts import assert_sql_result, assert_record_count_equals
 
@@ -56,10 +57,17 @@ def test_delete_book(empty_db, simple_book):
     service.mark_page_read(b.id, 1, False)
     service.mark_page_read(b.id, 1, True)
 
+    bss = BookStatsService(db.session)
+    bss.refresh_stats()
+
+    check_tables = ["books", "bookstats", "texts", "sentences", "booktags"]
+    for t in check_tables:
+        assert_record_count_equals(t, 1, f"{t} created")
+
     db.session.delete(b)
     db.session.commit()
 
-    for t in ["books", "texts", "sentences", "booktags"]:
+    for t in check_tables:
         assert_record_count_equals(t, 0, f"{t} deleted")
 
     sql = "select * from tags2"

tests/orm/test_Language.py

@@ -122,8 +122,8 @@ def test_delete_language_removes_book_and_terms(app_context, spanish):
     assert_sql_result(sqldict, ["something?[LUTE]"], "dict")
     assert_record_count_equals("select * from wordsread", 1, "saved")
 
-    repo = LanguageRepository(db.session)
-    repo.delete(spanish)
+    db.session.delete(spanish)
+    db.session.commit()
 
     assert_sql_result(sqlbook, [], "book deleted")
     assert_sql_result(sqlterms, [], "terms deleted")