Add migration to resolve bug remains

Author: raphaelm

libpretixsync/src/main/java/eu/pretix/libpretixsync/db/Migrations.java

@@ -15,7 +15,7 @@
 
 public class Migrations {
     private static EntityModel model = Models.DEFAULT;
-    public static int CURRENT_VERSION = 106;
+    public static int CURRENT_VERSION = 107;
 
     private static void createVersionTable(Connection c, int version) throws SQLException {
         Statement s2 = c.createStatement();
@@ -434,6 +434,11 @@ public static void migrate(DataSource dataSource, boolean dbIsNew) throws SQLExc
             execIgnore(c, "ALTER TABLE receiptline ADD tax_code TEXT NULL;", new String[] {"duplicate column name", "already exists", "existiert bereits"});
             updateVersionTable(c, 106);
         }
+        if (db_version < 107) {
+            // Version 4.3.6 contained a bug that wrote stringified null into this column.
+            execIgnore(c, "UPDATE ReceiptLine SET tax_code = NULL WHERE tax_code = 'null';", new String[] {"no such column", "existiert", "syntax error"});
+            updateVersionTable(c, 107);
+        }
 
         // Note that the Android app currently does not use these queries!
 
@@ -482,6 +487,11 @@ public static void android_manual_migrations(Connection c, int oldVersion, int n
             execIgnore(c, "ALTER TABLE settings DROP COLUMN covid_certificates_allow_vaccinated_products;", new String[] {"no such column", "existiert", "syntax error"});
             updateVersionTable(c, 105);
         }
+        if (oldVersion < 107 && newVersion >= 107) {
+            // Version 4.3.6 contained a bug that wrote stringified null into this column.
+            execIgnore(c, "UPDATE ReceiptLine SET tax_code = NULL WHERE tax_code = 'null';", new String[] {"no such column", "existiert", "syntax error"});
+            updateVersionTable(c, 107);
+        }
     }
 
     private static void create_drop(DataSource dataSource) {

libpretixsync/src/main/sqldelight/common/eu/pretix/libpretixsync/sqldelight/ReceiptLine.sq

@@ -105,4 +105,4 @@ VALUES (
     ?,
     ?,
     ?
-);
+);

libpretixsync/src/main/sqldelight/migrations/106.sqm

@@ -0,0 +1 @@
+UPDATE ReceiptLine SET tax_code = NULL WHERE tax_code = 'null';