Fix Geary crash when creating new database: Closes #5536

This also solves problem of creating a new folder after upgrading a
pre-schema 4 database.

src/engine/db/db-statement.vala

@@ -201,11 +201,11 @@ public class Geary.Db.Statement : Geary.Db.Context {
     /**
      * index is zero-based.
      *
-     * This is merely a front for bind_int64().  It's provided to offer more verbosity in the
-     * caller's code.
+     * This will bind the value to the column as an int64 unless it's INVALID_ROWID, in which case
+     * the column is bound as NULL.
      */
     public Statement bind_rowid(int index, int64 rowid) throws DatabaseError {
-        return bind_int64(index, rowid);
+        return (rowid != Db.INVALID_ROWID) ? bind_int64(index, rowid) : bind_null(index);
     }
     
     /**

src/engine/imap-db/imap-db-account.vala

@@ -100,20 +100,20 @@ private class Geary.ImapDB.Account : Object {
         Geary.FolderPath path = imap_folder.get_path();
         
         yield db.exec_transaction_async(Db.TransactionType.RW, (cx) => {
-            // get the parent of this folder, creating parents if necessary
-            int64 parent_id;
-            if (!do_fetch_parent_id(cx, path, true, out parent_id, cancellable))
-                return Db.TransactionOutcome.ROLLBACK;
+            // get the parent of this folder, creating parents if necessary ... ok if this fails,
+            // that just means the folder has no parents
+            int64 parent_id = Db.INVALID_ROWID;
+            do_fetch_parent_id(cx, path, true, out parent_id, cancellable);
             
             // create the folder object
             Db.Statement stmt = cx.prepare(
                 "INSERT INTO FolderTable (name, parent_id, last_seen_total, uid_validity, uid_next, attributes) "
-                + "VALUES (?, ?, ?, ?, ?)");
+                + "VALUES (?, ?, ?, ?, ?, ?)");
             stmt.bind_string(0, path.basename);
             stmt.bind_rowid(1, parent_id);
             stmt.bind_int(2, properties.messages);
-            stmt.bind_int64(3, properties.uid_validity.value);
-            stmt.bind_int64(4, properties.uid_next.value);
+            stmt.bind_int64(3, (properties.uid_validity != null) ?  properties.uid_validity.value : 0);
+            stmt.bind_int64(4, (properties.uid_next != null) ? properties.uid_next.value : 0);
             stmt.bind_string(5, properties.attrs.serialize());
             
             stmt.exec(cancellable);

src/engine/impl/geary-generic-imap-account.vala

@@ -276,7 +276,10 @@ private abstract class Geary.GenericImapAccount : Geary.EngineAccount {
                     engine_added.add(build_folder((ImapDB.Folder) yield local.fetch_folder_async(
                         remote_folder.get_path(), cancellable)));
                 } catch (Error convert_err) {
-                    error("Unable to fetch local folder: %s", convert_err.message);
+                    // This isn't fatal, but irksome ... in the future, when local folders are
+                    // removed, it's possible for one to disappear between cloning it and fetching
+                    // it
+                    debug("Unable to fetch local folder after cloning: %s", convert_err.message);
                 }
             }
         }