Don't create 2 new books for every new session.

And don't ask to save a not-dirty or empty book, fixing
Bug 794870 - If no book is opened, gnucash still asks if the user wants
to save changes when opening a file

gnucash/gnome-utils/gnc-main-window.c

@@ -1238,6 +1238,8 @@ gnc_main_window_prompt_for_save (GtkWidget *window)
         return FALSE;
     session = gnc_get_current_session();
     book = qof_session_get_book(session);
+    if (!qof_book_session_not_saved(book))
+        return FALSE;
     filename = qof_session_get_url(session);
     if (!strlen (filename))
         filename = _("<unknown>");

libgnucash/backend/sql/test/utest-gnc-backend-sql.cpp

@@ -298,6 +298,7 @@ test_gnc_sql_commit_edit (void)
     qof_instance_init_data (inst, QOF_ID_NULL, book);
     qof_book_set_dirty_cb (book, test_dirty_cb, &dirty_called);
     qof_instance_set_dirty_flag (inst, TRUE);
+    gnc_account_create_root (book);
     qof_book_mark_session_dirty (book);
 
     g_assert (qof_instance_get_dirty_flag (inst));

libgnucash/engine/qofbook.cpp

@@ -58,6 +58,8 @@ extern "C"
 #include "qofobject-p.h"
 #include "qofbookslots.h"
 #include "kvp-frame.hpp"
+// For GNC_ID_ROOT_ACCOUNT:
+#include "AccountP.h"
 
 static QofLogModule log_module = QOF_MOD_ENGINE;
 #define AB_KEY "hbci"
@@ -456,7 +458,7 @@ gboolean
 qof_book_session_not_saved (const QofBook *book)
 {
     if (!book) return FALSE;
-    return book->session_dirty;
+    return !qof_book_empty(book) && book->session_dirty;
 
 }
 
@@ -585,6 +587,15 @@ qof_book_mark_readonly(QofBook *book)
     g_return_if_fail( book != NULL );
     book->read_only = TRUE;
 }
+
+gboolean
+qof_book_empty(const QofBook *book)
+{
+    if (!book) return TRUE;
+    auto root_acct_col = qof_book_get_collection (book, GNC_ID_ROOT_ACCOUNT);
+    return qof_collection_get_data(root_acct_col) == nullptr;
+}
+
 /* ====================================================================== */
 
 QofCollection *

libgnucash/engine/qofbook.h

@@ -258,6 +258,9 @@ gboolean qof_book_is_readonly(const QofBook *book);
 /** Mark the book as read only. */
 void qof_book_mark_readonly(QofBook *book);
 
+/** Check if the book has had anything loaded into it. */
+gboolean qof_book_empty(const QofBook *book);
+
 #endif /* SWIG */
 
 /** Returns flag indicating whether this book uses trading accounts */

libgnucash/engine/qofsession.cpp

@@ -125,7 +125,6 @@ QofSessionImpl::QofSessionImpl () noexcept
     m_last_err {},
     m_error_message {}
 {
-    clear_error ();
 }
 
 QofSessionImpl::~QofSessionImpl () noexcept
@@ -201,44 +200,23 @@ QofSessionImpl::load_backend (std::string access_method) noexcept
 void
 QofSessionImpl::load (QofPercentageFunc percentage_func) noexcept
 {
+    /* We must have an empty book to load into or bad things will happen. */
+    g_return_if_fail(m_book && qof_book_empty(m_book));
+    
     if (!m_book_id.size ()) return;
     ENTER ("sess=%p book_id=%s", this, m_book_id.c_str ());
 
     /* At this point, we should are supposed to have a valid book
     * id and a lock on the file. */
-    QofBook * oldbook {m_book};
-
-    QofBook * newbook {qof_book_new ()};
-    m_book = newbook;
-    PINFO ("new book=%p", newbook);
     clear_error ();
-
-    /* This code should be sufficient to initialize *any* backend,
-    * whether http, postgres, or anything else that might come along.
-    * Basically, the idea is that by now, a backend has already been
-    * created & set up.  At this point, we only need to get the
-    * top-level account group out of the backend, and that is a
-    * generic, backend-independent operation.
-    */
-    auto be (qof_book_get_backend (oldbook));
-    qof_book_set_backend (newbook, be);
-
-    /* Starting the session should result in a bunch of accounts
-    * and currencies being downloaded, but probably no transactions;
-    * The GUI will need to do a query for that.
-    */
+    auto be (qof_book_get_backend(m_book));
     if (be)
     {
         be->set_percentage(percentage_func);
-        be->load (newbook, LOAD_TYPE_INITIAL_LOAD);
+        be->load (m_book, LOAD_TYPE_INITIAL_LOAD);
         push_error (be->get_error(), {});
     }
 
-    /* XXX if the load fails, then we try to restore the old set of books;
-    * however, we don't undo the session id (the URL).  Thus if the
-    * user attempts to save after a failed load, they weill be trying to
-    * save to some bogus URL.   This is wrong. XXX  FIXME.
-    */
     auto err = get_error ();
     if ((err != ERR_BACKEND_NO_ERR) &&
             (err != ERR_FILEIO_FILE_TOO_OLD) &&
@@ -247,16 +225,11 @@ QofSessionImpl::load (QofPercentageFunc percentage_func) noexcept
             (err != ERR_SQL_DB_TOO_OLD) &&
             (err != ERR_SQL_DB_TOO_NEW))
     {
-        /* Something broke, put back the old stuff */
-        qof_book_set_backend (newbook, NULL);
-        qof_book_destroy (newbook);
-        m_book = oldbook;
+        qof_book_destroy(m_book);
+        m_book = qof_book_new();
         LEAVE ("error from backend %d", get_error ());
         return;
     }
-    qof_book_set_backend (oldbook, NULL);
-    qof_book_destroy (oldbook);
-
     LEAVE ("sess = %p, book_id=%s", this, m_book_id.c_str ());
 }
 

libgnucash/engine/test/test-qofbook.c

@@ -36,6 +36,8 @@ extern "C"
 #include "../qof.h"
 #include "../qofbook-p.h"
 #include "../qofbookslots.h"
+/* For gnc_account_create_root() */
+#include "../Account.h"
 
 static const gchar *suitename = "/qof/qofbook";
 void test_suite_qofbook ( void );
@@ -285,6 +287,7 @@ test_book_session_not_saved( Fixture *fixture, gconstpointer pData )
     g_assert( !qof_book_session_not_saved( fixture->book ) );
     qof_book_mark_session_saved( fixture->book );
     g_assert( !qof_book_session_not_saved( fixture->book ) );
+    gnc_account_create_root (fixture->book);
     qof_book_mark_session_dirty( fixture-> book );
     g_assert( qof_book_session_not_saved( fixture->book ) );
 }
@@ -294,6 +297,7 @@ test_book_mark_session_saved( Fixture *fixture, gconstpointer pData )
 {
     time64 dirty_time, clean_time;
 
+    gnc_account_create_root (fixture->book);
     qof_book_mark_session_dirty( fixture-> book );
     g_assert( qof_book_session_not_saved( fixture->book ) );
     dirty_time = qof_book_get_session_dirty_time( fixture->book );
@@ -626,6 +630,7 @@ test_book_mark_session_dirty( Fixture *fixture, gconstpointer pData )
     g_assert( fixture->book->dirty_cb == NULL );
     g_assert( qof_book_session_not_saved( fixture->book ) == FALSE );
     before = gnc_time (NULL);
+    gnc_account_create_root (fixture->book);
     qof_book_mark_session_dirty( fixture->book );
     after = gnc_time (NULL);
     g_assert_cmpint( qof_book_get_session_dirty_time( fixture->book ), >= , before);

libgnucash/engine/test/test-qofsession.cpp

@@ -28,6 +28,7 @@
 #include <qof-backend.hpp>
 #include <cstdlib>
 #include "../gnc-backend-prov.hpp"
+#include "../Account.h"
 
 static QofBook * exported_book {nullptr};
 static bool safe_sync_called {false};
@@ -57,9 +58,12 @@ example_hook (QofSession & session)
     hook_called = true;
 }
 
-void QofSessionMockBackend::load (QofBook *, QofBackendLoadType)
+void QofSessionMockBackend::load (QofBook *book, QofBackendLoadType)
 {
-    if (load_error) set_error(ERR_BACKEND_NO_BACKEND);
+    if (load_error)
+        set_error(ERR_BACKEND_NO_BACKEND);
+    else
+        auto root = gnc_account_create_root (book);
     data_loaded = true;
 }
 
@@ -178,10 +182,13 @@ TEST (QofSessionTest, load)
     EXPECT_EQ (book, s.get_book ());
 
     // Now we'll do the load without returning an error from the backend,
-    // and ensure that the book changed to a new book.
+    // and ensure that it's the original book and that it's not empty.
     load_error = false;
     s.load (nullptr);
-    EXPECT_NE (book, s.get_book ());
+    EXPECT_EQ (book, s.get_book ());
+    EXPECT_EQ (s.get_error(), ERR_BACKEND_NO_ERR);
+    //But it's still empty, to the book shouldn't need saving
+    EXPECT_FALSE(qof_book_session_not_saved (s.get_book ()));
     // I'll put load_error back just to be tidy.
     load_error = true;
     qof_backend_unregister_all_providers ();
@@ -192,11 +199,14 @@ TEST (QofSessionTest, save)
     qof_backend_register_provider (get_provider ());
     QofSession s;
     s.begin ("book1", false, false, false);
+    load_error = false;
+    s.load (nullptr);
     qof_book_mark_session_dirty (s.get_book ());
     s.save (nullptr);
     EXPECT_EQ (sync_called, true);
     qof_backend_unregister_all_providers ();
     sync_called = false;
+    load_error = true;
 }
 
 TEST (QofSessionTest, safe_save)