From 7c03e237b228032da14b655f79822894b955789b Mon Sep 17 00:00:00 2001
From: "J. Alex Aycinena" <alex.aycinena@gmail.com>
Date: Sun, 29 Jan 2012 01:12:30 +0000
Subject: [PATCH] Update xml file backend to recognize a newer version file on
 load attempt, not load, and alert user of need to upgrade Gnucash.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@21908 57a11ea4-9604-0410-9ed3-97b8803252fd
---
 src/backend/xml/gnc-backend-xml.c             | 37 +++++-----
 src/backend/xml/gnc-backend-xml.h             | 10 +++
 src/backend/xml/io-example-account.c          |  3 +-
 src/backend/xml/io-example-account.h          |  2 +-
 src/backend/xml/io-gncxml-v1.c                |  4 +-
 src/backend/xml/io-gncxml-v2.c                | 35 ++++++----
 src/backend/xml/io-gncxml-v2.h                |  4 +-
 src/backend/xml/sixtp.c                       | 70 ++++++++++---------
 src/backend/xml/sixtp.h                       |  6 +-
 src/backend/xml/test/test-date-converting.c   |  3 +
 src/backend/xml/test/test-dom-converters1.c   |  3 +
 src/backend/xml/test/test-kvp-frames.c        |  2 +
 src/backend/xml/test/test-string-converters.c |  3 +
 src/backend/xml/test/test-xml-account.c       |  3 +
 src/backend/xml/test/test-xml-commodity.c     |  3 +
 src/backend/xml/test/test-xml-pricedb.c       |  3 +
 src/gnome-utils/gnc-file.c                    | 13 +++-
 src/libqof/qof/qofbackend.h                   |  2 +
 src/libqof/qof/qofsession.c                   |  1 +
 19 files changed, 134 insertions(+), 73 deletions(-)

diff --git a/src/backend/xml/gnc-backend-xml.c b/src/backend/xml/gnc-backend-xml.c
index 2b8f1f2b3f..69e8f2df01 100644
--- a/src/backend/xml/gnc-backend-xml.c
+++ b/src/backend/xml/gnc-backend-xml.c
@@ -99,15 +99,6 @@ typedef int ssize_t;
 
 static QofLogModule log_module = GNC_MOD_BACKEND;
 
-typedef enum
-{
-    GNC_BOOK_NOT_OURS,
-    GNC_BOOK_BIN_FILE,
-    GNC_BOOK_XML1_FILE,
-    GNC_BOOK_XML2_FILE,
-    GNC_BOOK_XML2_FILE_NO_ENCODING,
-} QofBookFileType;
-
 static gboolean save_may_clobber_data (QofBackend *bend);
 
 /* ================================================================= */
@@ -561,7 +552,10 @@ static QofBookFileType
 gnc_xml_be_determine_file_type(const char *path)
 {
     gboolean with_encoding;
-    if (gnc_is_xml_data_file_v2(path, &with_encoding))
+    QofBookFileType v2type;
+
+    v2type = gnc_is_xml_data_file_v2(path, &with_encoding);
+    if (v2type == GNC_BOOK_XML2_FILE)
     {
         if (with_encoding)
         {
@@ -572,7 +566,11 @@ gnc_xml_be_determine_file_type(const char *path)
             return GNC_BOOK_XML2_FILE_NO_ENCODING;
         }
     }
-    else if (gnc_is_xml_data_file(path))
+    else if (v2type == GNC_BOOK_POST_XML2_0_0_FILE)
+    {
+        return GNC_BOOK_POST_XML2_0_0_FILE;
+    }
+    else if (v2type == GNC_BOOK_XML1_FILE)
     {
         return GNC_BOOK_XML1_FILE;
     }
@@ -586,6 +584,7 @@ gnc_determine_file_type (const char *uri)
     int rc;
     FILE *t;
     gchar *filename;
+    QofBookFileType xml_type;
     gboolean result;
 
     if (!uri)
@@ -619,12 +618,10 @@ gnc_determine_file_type (const char *uri)
         result = TRUE;
         goto det_exit;
     }
-    if (gnc_is_xml_data_file_v2(filename, NULL))
-    {
-        result = TRUE;
-        goto det_exit;
-    }
-    else if (gnc_is_xml_data_file(filename))
+    xml_type = gnc_is_xml_data_file_v2(filename, NULL);
+    if ((xml_type == GNC_BOOK_XML2_FILE) ||
+        (xml_type == GNC_BOOK_XML1_FILE) ||
+        (xml_type == GNC_BOOK_POST_XML2_0_0_FILE))
     {
         result = TRUE;
         goto det_exit;
@@ -1117,7 +1114,7 @@ gnc_xml_be_load_from_file (QofBackend *bend, QofBook *book, QofBackendLoadType l
     switch (gnc_xml_be_determine_file_type(be->fullpath))
     {
     case GNC_BOOK_XML2_FILE:
-        rc = qof_session_load_from_xml_file_v2 (be, book);
+        rc = qof_session_load_from_xml_file_v2 (be, book, GNC_BOOK_XML2_FILE);
         if (FALSE == rc)
         {
             PWARN( "Syntax error in Xml File %s", be->fullpath );
@@ -1137,6 +1134,10 @@ gnc_xml_be_load_from_file (QofBackend *bend, QofBook *book, QofBackendLoadType l
             error = ERR_FILEIO_PARSE_ERROR;
         }
         break;
+    case GNC_BOOK_POST_XML2_0_0_FILE:
+        error = ERR_BACKEND_TOO_NEW;
+        PWARN( "Version of Xml file %s is newer than what we can read", be->fullpath );
+        break;
     default:
         /* If file type wasn't known, check errno again to give the
         user some more useful feedback for some particular error
diff --git a/src/backend/xml/gnc-backend-xml.h b/src/backend/xml/gnc-backend-xml.h
index 959956a363..4d69c89158 100644
--- a/src/backend/xml/gnc-backend-xml.h
+++ b/src/backend/xml/gnc-backend-xml.h
@@ -43,6 +43,16 @@ typedef enum
     XML_RETAIN_ALL
 } XMLFileRetentionType;
 
+typedef enum
+{
+    GNC_BOOK_NOT_OURS,
+    GNC_BOOK_BIN_FILE,
+    GNC_BOOK_XML1_FILE,
+    GNC_BOOK_XML2_FILE,
+    GNC_BOOK_XML2_FILE_NO_ENCODING,
+    GNC_BOOK_POST_XML2_0_0_FILE
+} QofBookFileType;
+
 struct FileBackend_struct
 {
     QofBackend be;
diff --git a/src/backend/xml/io-example-account.c b/src/backend/xml/io-example-account.c
index b734a49d84..f1b2d9a125 100644
--- a/src/backend/xml/io-example-account.c
+++ b/src/backend/xml/io-example-account.c
@@ -498,8 +498,9 @@ gnc_load_example_account_list(const char *dirname)
 
 
 /***********************************************************************/
+/*
 gboolean
 gnc_is_example_account_xml(const gchar *name)
 {
     return gnc_is_our_xml_file(name, GNC_ACCOUNT_STRING, NULL);
-}
+} */
diff --git a/src/backend/xml/io-example-account.h b/src/backend/xml/io-example-account.h
index 41a4349805..914f308655 100644
--- a/src/backend/xml/io-example-account.h
+++ b/src/backend/xml/io-example-account.h
@@ -53,6 +53,6 @@ GncExampleAccount *gnc_read_example_account(const gchar *filename);
 void gnc_free_example_account_list(GSList *list);
 GSList* gnc_load_example_account_list(const char *dirname);
 
-gboolean gnc_is_example_account_xml(const gchar *name);
+/* gboolean gnc_is_example_account_xml(const gchar *name); */
 
 #endif /* IO_EXAMPLE_ACCOUNT_H */
diff --git a/src/backend/xml/io-gncxml-v1.c b/src/backend/xml/io-gncxml-v1.c
index 4b71b3f67b..6e22f4a26a 100644
--- a/src/backend/xml/io-gncxml-v1.c
+++ b/src/backend/xml/io-gncxml-v1.c
@@ -412,7 +412,9 @@ qof_session_load_from_xml_file(QofBook *book, const char *filename)
 gboolean
 gnc_is_xml_data_file(const gchar *filename)
 {
-    return gnc_is_our_xml_file(filename, "gnc", NULL);
+    if ((gnc_is_our_xml_file(filename, NULL)) == GNC_BOOK_XML1_FILE)
+        return TRUE;
+    return FALSE;
 }
 
 /* ================================================================== */
diff --git a/src/backend/xml/io-gncxml-v2.c b/src/backend/xml/io-gncxml-v2.c
index 51b829a458..3ea6af8df3 100644
--- a/src/backend/xml/io-gncxml-v2.c
+++ b/src/backend/xml/io-gncxml-v2.c
@@ -95,6 +95,8 @@ struct file_backend
 };
 
 #define GNC_V2_STRING "gnc-v2"
+/* non-static because they are used in sixtp.c */
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
 extern const gchar *gnc_v2_book_version_string;        /* see gnc-book-xml-v2 */
 
 void
@@ -679,7 +681,8 @@ gnc_sixtp_gdv2_new (
 static gboolean
 qof_session_load_from_xml_file_v2_full(
     FileBackend *fbe, QofBook *book,
-    sixtp_push_handler push_handler, gpointer push_user_data)
+    sixtp_push_handler push_handler, gpointer push_user_data,
+    QofBookFileType type)
 {
     Account *root;
     QofBackend *be = &fbe->be;
@@ -689,6 +692,7 @@ qof_session_load_from_xml_file_v2_full(
     sixtp *book_parser;
     struct file_backend be_data;
     gboolean retval;
+    char *v2type;
 
     gd = gnc_sixtp_gdv2_new(book, FALSE, file_rw_feedback, be->percentage);
 
@@ -696,14 +700,20 @@ qof_session_load_from_xml_file_v2_full(
     main_parser = sixtp_new();
     book_parser = sixtp_new();
 
+    if (type == GNC_BOOK_XML2_FILE)
+        v2type = g_strdup(GNC_V2_STRING);
+
     if (!sixtp_add_some_sub_parsers(
                 top_parser, TRUE,
-                GNC_V2_STRING, main_parser,
+                v2type, main_parser,
                 NULL, NULL))
     {
+        g_free(v2type);
         goto bail;
     }
 
+    g_free(v2type);
+
     if (!sixtp_add_some_sub_parsers(
                 main_parser, TRUE,
                 COUNT_DATA_TAG, gnc_counter_sixtp_parser_create(),
@@ -819,9 +829,10 @@ bail:
 }
 
 gboolean
-qof_session_load_from_xml_file_v2(FileBackend *fbe, QofBook *book)
+qof_session_load_from_xml_file_v2(FileBackend *fbe, QofBook *book,
+    QofBookFileType type)
 {
-    return qof_session_load_from_xml_file_v2_full(fbe, book, NULL, NULL);
+    return qof_session_load_from_xml_file_v2_full(fbe, book, NULL, NULL, type);
 }
 
 /***********************************************************************/
@@ -1620,12 +1631,9 @@ is_gzipped_file(const gchar *name)
     return FALSE;
 }
 
-gboolean
+QofBookFileType
 gnc_is_xml_data_file_v2(const gchar *name, gboolean *with_encoding)
 {
-    if (gnc_is_our_xml_file(name, GNC_V2_STRING, with_encoding))
-        return TRUE;
-
     if (is_gzipped_file(name))
     {
         gzFile *file = NULL;
@@ -1647,19 +1655,18 @@ gnc_is_xml_data_file_v2(const gchar *name, gboolean *with_encoding)
         file = gzopen(name, "r");
 #endif
         if (file == NULL)
-            return FALSE;
+            return GNC_BOOK_NOT_OURS;
 
         num_read = gzread(file, first_chunk, sizeof(first_chunk) - 1);
         gzclose(file);
 
         if (num_read < 1)
-            return FALSE;
+            return GNC_BOOK_NOT_OURS;
 
-        return gnc_is_our_first_xml_chunk(first_chunk, GNC_V2_STRING,
-                                          with_encoding);
+        return gnc_is_our_first_xml_chunk(first_chunk, with_encoding);
     }
 
-    return FALSE;
+    return (gnc_is_our_xml_file(name, with_encoding));
 }
 
 
@@ -2095,7 +2102,7 @@ gnc_xml2_parse_with_subst (FileBackend *fbe, QofBook *book, GHashTable *subst)
 
     success = qof_session_load_from_xml_file_v2_full(
                   fbe, book, (sixtp_push_handler) parse_with_subst_push_handler,
-                  push_data);
+                  push_data, GNC_BOOK_XML2_FILE);
 
     if (success)
         qof_book_kvp_changed(book);
diff --git a/src/backend/xml/io-gncxml-v2.h b/src/backend/xml/io-gncxml-v2.h
index 36d9858240..6fc7145b47 100644
--- a/src/backend/xml/io-gncxml-v2.h
+++ b/src/backend/xml/io-gncxml-v2.h
@@ -128,7 +128,7 @@ typedef struct
 void run_callback(sixtp_gdv2 *data, const char *type);
 
 /** read in an account group from a file */
-gboolean qof_session_load_from_xml_file_v2(FileBackend *, QofBook *);
+gboolean qof_session_load_from_xml_file_v2(FileBackend *, QofBook *, QofBookFileType);
 
 /* write all book info to a file */
 gboolean gnc_book_write_to_xml_filehandle_v2(QofBook *book, FILE *fh);
@@ -142,7 +142,7 @@ gboolean gnc_book_write_accounts_to_xml_file_v2(QofBackend * be, QofBook *book,
 /** The is_gncxml_file() routine checks to see if the first few
  * chars of the file look like gnc-xml data.
  */
-gboolean gnc_is_xml_data_file_v2(const gchar *name, gboolean *with_encoding);
+QofBookFileType gnc_is_xml_data_file_v2(const gchar *name, gboolean *with_encoding);
 
 /** Write a name-space declaration for the provided namespace data type
  * within the GNC XML namespace at http://www.gnucash.org/XML.
diff --git a/src/backend/xml/sixtp.c b/src/backend/xml/sixtp.c
index 34ccf22cc5..31e6d291ad 100644
--- a/src/backend/xml/sixtp.c
+++ b/src/backend/xml/sixtp.c
@@ -41,6 +41,8 @@ typedef int ssize_t;
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "gnc.backend.file.sixtp"
 
+extern const gchar *gnc_v2_xml_version_string;        /* see io-gncxml-v2.c */
+
 /************************************************************************/
 gboolean
 is_child_result_from_node_named(sixtp_child_result *cr, const char *tag)
@@ -860,21 +862,19 @@ search_for(unsigned char marker, char **cursor)
     }
 }
 
-gboolean
-gnc_is_our_xml_file(const char *filename, const char *first_tag,
-                    gboolean *with_encoding)
+QofBookFileType
+gnc_is_our_xml_file(const char *filename, gboolean *with_encoding)
 {
     FILE *f = NULL;
     char first_chunk[256];
     ssize_t num_read;
 
-    g_return_val_if_fail(filename, FALSE);
-    g_return_val_if_fail(first_tag, FALSE);
+    g_return_val_if_fail(filename, GNC_BOOK_NOT_OURS);
 
     f = g_fopen(filename, "r");
     if (f == NULL)
     {
-        return FALSE;
+        return GNC_BOOK_NOT_OURS;
     }
 
     num_read = fread(first_chunk, sizeof(char), sizeof(first_chunk) - 1, f);
@@ -882,17 +882,16 @@ gnc_is_our_xml_file(const char *filename, const char *first_tag,
 
     if (num_read == 0)
     {
-        return FALSE;
+        return GNC_BOOK_NOT_OURS;
     }
 
     first_chunk[num_read] = '\0';
 
-    return gnc_is_our_first_xml_chunk(first_chunk, first_tag, with_encoding);
+    return gnc_is_our_first_xml_chunk(first_chunk, with_encoding);
 }
 
-gboolean
-gnc_is_our_first_xml_chunk(char *chunk, const char *first_tag,
-                           gboolean *with_encoding)
+QofBookFileType
+gnc_is_our_first_xml_chunk(char *chunk, gboolean *with_encoding)
 {
     char *cursor = NULL;
 
@@ -905,51 +904,58 @@ gnc_is_our_first_xml_chunk(char *chunk, const char *first_tag,
 
     if (!eat_whitespace(&cursor))
     {
-        return FALSE;
+        return GNC_BOOK_NOT_OURS;
     }
 
     if (strncmp(cursor, "<?xml", 5) == 0)
     {
         char *tag_compare;
-        gboolean result;
 
         if (!search_for('>', &cursor))
         {
-            return FALSE;
+            return GNC_BOOK_NOT_OURS;
         }
 
         if (!eat_whitespace(&cursor))
         {
-            return FALSE;
+            return GNC_BOOK_NOT_OURS;
         }
 
-        tag_compare = g_strdup_printf("<%s", first_tag);
+        tag_compare = g_strdup_printf("<%s\n", gnc_v2_xml_version_string);
 
-        result = (strncmp(cursor, tag_compare, strlen(tag_compare)) == 0);
-        g_free (tag_compare);
-
-        if (result && with_encoding)
+        if (strncmp(cursor, tag_compare, strlen(tag_compare)) == 0)
         {
-            *cursor = '\0';
-            cursor = chunk;
-            while (search_for('e', &cursor))
+            if (with_encoding)
             {
-                if (strncmp(cursor, "ncoding=", 8) == 0)
+                *cursor = '\0';
+                cursor = chunk;
+                while (search_for('e', &cursor))
                 {
-                    *with_encoding = TRUE;
-                    break;
+                    if (strncmp(cursor, "ncoding=", 8) == 0)
+                    {
+                        *with_encoding = TRUE;
+                        break;
+                    }
                 }
             }
+            g_free (tag_compare);
+            return GNC_BOOK_XML2_FILE;
         }
 
-        return result;
-    }
-    else
-    {
-        return FALSE;
+        g_free (tag_compare);
+
+        if (strncmp(cursor, "<gnc>\n", strlen("<gnc>\n")) == 0)
+            return GNC_BOOK_XML1_FILE;
+
+        /* If it doesn't match any of the above but has '<gnc-v...', it must */
+        /* be a later version */
+        if (strncmp(cursor, "<gnc-v", strlen("<gnc-v")) == 0)
+            return GNC_BOOK_POST_XML2_0_0_FILE;
+
+        return GNC_BOOK_NOT_OURS;
     }
 
-    return FALSE;
+    return GNC_BOOK_NOT_OURS;
 }
 
 /************************* END OF FILE *********************************/
diff --git a/src/backend/xml/sixtp.h b/src/backend/xml/sixtp.h
index 06ebb2ac0e..08097e1d0c 100644
--- a/src/backend/xml/sixtp.h
+++ b/src/backend/xml/sixtp.h
@@ -31,6 +31,7 @@
 
 #include "gnc-xml-helper.h"
 #include "gnc-engine.h"
+#include "gnc-backend-xml.h"
 
 typedef struct _sixtp_child_result sixtp_child_result;
 
@@ -208,11 +209,10 @@ sixtp* sixtp_add_some_sub_parsers(sixtp *tochange, gboolean cleanup, ...);
 gboolean sixtp_add_sub_parser(sixtp *parser, const gchar* tag,
                               sixtp *sub_parser);
 
-gboolean gnc_is_our_xml_file(const char *filename, const char *first_tag,
+QofBookFileType gnc_is_our_xml_file(const char *filename,
                              gboolean *with_encoding);
 
-gboolean gnc_is_our_first_xml_chunk(char *chunk, const char *first_tag,
-                                    gboolean *with_encoding);
+QofBookFileType gnc_is_our_first_xml_chunk(char *chunk, gboolean *with_encoding);
 
 
 #endif /* _SIXTP_H_ */
diff --git a/src/backend/xml/test/test-date-converting.c b/src/backend/xml/test/test-date-converting.c
index a7ed401901..050822cfc8 100644
--- a/src/backend/xml/test/test-date-converting.c
+++ b/src/backend/xml/test/test-date-converting.c
@@ -10,6 +10,9 @@
 #include "sixtp-utils.h"
 #include "sixtp-dom-generators.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 int
 main(int argc, char **argv)
 {
diff --git a/src/backend/xml/test/test-dom-converters1.c b/src/backend/xml/test/test-dom-converters1.c
index f6d8f62d09..f3b3d09f83 100644
--- a/src/backend/xml/test/test-dom-converters1.c
+++ b/src/backend/xml/test/test-dom-converters1.c
@@ -43,6 +43,9 @@
 
 #include "gnc-commodity.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 static void
 test_dom_tree_to_commodity_ref(void)
 {
diff --git a/src/backend/xml/test/test-kvp-frames.c b/src/backend/xml/test/test-kvp-frames.c
index 0d06001921..0bbd8e7de9 100644
--- a/src/backend/xml/test/test-kvp-frames.c
+++ b/src/backend/xml/test/test-kvp-frames.c
@@ -11,6 +11,8 @@
 #include "sixtp-dom-generators.h"
 #include "sixtp-dom-parsers.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
 
 static void
 test_kvp_get_slot(int run,
diff --git a/src/backend/xml/test/test-string-converters.c b/src/backend/xml/test/test-string-converters.c
index bbc3a3a032..582431f107 100644
--- a/src/backend/xml/test/test-string-converters.c
+++ b/src/backend/xml/test/test-string-converters.c
@@ -11,6 +11,9 @@
 #include "test-engine-stuff.h"
 #include "test-file-stuff.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 static void
 test_binary()
 {
diff --git a/src/backend/xml/test/test-xml-account.c b/src/backend/xml/test/test-xml-account.c
index 0489d679cf..415264d734 100644
--- a/src/backend/xml/test/test-xml-account.c
+++ b/src/backend/xml/test/test-xml-account.c
@@ -43,6 +43,9 @@
 #include "Account.h"
 #include "Scrub.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 static QofBook *sixbook;
 
 static gchar*
diff --git a/src/backend/xml/test/test-xml-commodity.c b/src/backend/xml/test/test-xml-commodity.c
index cf6cb468bf..e55ccb75a6 100644
--- a/src/backend/xml/test/test-xml-commodity.c
+++ b/src/backend/xml/test/test-xml-commodity.c
@@ -24,6 +24,9 @@
 
 #include "Account.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 static QofBook *book;
 
 static gchar*
diff --git a/src/backend/xml/test/test-xml-pricedb.c b/src/backend/xml/test/test-xml-pricedb.c
index d2f55be8bb..a2b133b25e 100644
--- a/src/backend/xml/test/test-xml-pricedb.c
+++ b/src/backend/xml/test/test-xml-pricedb.c
@@ -42,6 +42,9 @@
 #include "test-engine-stuff.h"
 #include "test-file-stuff.h"
 
+#define GNC_V2_STRING "gnc-v2"
+const gchar *gnc_v2_xml_version_string = GNC_V2_STRING;
+
 static QofSession *session;
 
 struct pricedb_data_struct
diff --git a/src/gnome-utils/gnc-file.c b/src/gnome-utils/gnc-file.c
index 32bcc6e8ec..a23283ab39 100644
--- a/src/gnome-utils/gnc-file.c
+++ b/src/gnome-utils/gnc-file.c
@@ -421,7 +421,8 @@ show_session_error (QofBackendError io_error,
     case ERR_SQL_DB_TOO_NEW:
         fmt = _("This database is from a newer version of GnuCash. "
                 "This version can read it, but cannot safely save to it. "
-                "It will be marked read-only until you do File>Save As.");
+                "It will be marked read-only until you do File>Save As, "
+                "but data may be lost in writing to the old version.");
         gnc_warning_dialog (parent, "%s", fmt);
         uh_oh = TRUE;
         break;
@@ -458,6 +459,16 @@ show_session_error (QofBackendError io_error,
         gnc_error_dialog (parent, "%s", fmt);
         break;
 
+    case ERR_FILEIO_FILE_UPGRADE:
+        fmt = _("This file is from an older version of GnuCash and will be "
+                "upgraded when saved by this version. You will not be able "
+                "to read the saved file from the older version of Gnucash "
+                "(it will report an \"error parsing the file\"). If you wish "
+                "to preserve the old version, exit without saving.");
+        gnc_warning_dialog (parent, "%s", fmt);
+        uh_oh = FALSE;
+        break;
+
     default:
         PERR("FIXME: Unhandled error %d", io_error);
         fmt = _("An unknown I/O error (%d) occurred.");
diff --git a/src/libqof/qof/qofbackend.h b/src/libqof/qof/qofbackend.h
index 2c8f6d73a9..13aed89c4d 100644
--- a/src/libqof/qof/qofbackend.h
+++ b/src/libqof/qof/qofbackend.h
@@ -98,6 +98,8 @@ typedef enum
     ERR_FILEIO_FILE_EACCES,    /**< No read access permission for the given file */
     ERR_FILEIO_RESERVED_WRITE, /**< User attempt to write to a directory reserved
                                     for internal use by GnuCash */
+    ERR_FILEIO_FILE_UPGRADE,   /**< file will be upgraded and not be able to be
+                                    read by prior versions - warn users*/
 
     /* network errors */
     ERR_NETIO_SHORT_READ = 2000,  /**< not enough bytes received */
diff --git a/src/libqof/qof/qofsession.c b/src/libqof/qof/qofsession.c
index 9ce5052d8a..db203e3beb 100644
--- a/src/libqof/qof/qofsession.c
+++ b/src/libqof/qof/qofsession.c
@@ -1257,6 +1257,7 @@ qof_session_load (QofSession *session,
     if ((err != ERR_BACKEND_NO_ERR) &&
             (err != ERR_FILEIO_FILE_TOO_OLD) &&
             (err != ERR_FILEIO_NO_ENCODING) &&
+            (err != ERR_FILEIO_FILE_UPGRADE) &&
             (err != ERR_SQL_DB_TOO_OLD) &&
             (err != ERR_SQL_DB_TOO_NEW))
     {