From 46596e865287774175518b68e5278100cea0d30b Mon Sep 17 00:00:00 2001
From: Daniel Gultsch <daniel@gultsch.de>
Date: Thu, 7 Mar 2019 09:08:32 +0100
Subject: [PATCH] fix backup creation for older installations

if your Conversations installation is older than December 2016 (version 1.15.0) the backup would
include historic data that a current installation is not able to read on restore.
This commits excludes that data from the backup.
If you had problems importing the backup you need to create a new backup after this patch
---
 .../services/ExportBackupService.java          | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/main/java/eu/siacs/conversations/services/ExportBackupService.java b/src/main/java/eu/siacs/conversations/services/ExportBackupService.java
index f335f8bf0..16e1662cb 100644
--- a/src/main/java/eu/siacs/conversations/services/ExportBackupService.java
+++ b/src/main/java/eu/siacs/conversations/services/ExportBackupService.java
@@ -145,25 +145,32 @@ public class ExportBackupService extends Service {
         return cursorToString(tablename, cursor, max, false);
     }
 
-    private static String cursorToString(String tablename, Cursor cursor, int max, boolean ignore) {
+    private static String cursorToString(final String tablename, final Cursor cursor, int max, boolean ignore) {
+        final boolean identities = SQLiteAxolotlStore.IDENTITIES_TABLENAME.equals(tablename);
         StringBuilder builder = new StringBuilder();
         builder.append("INSERT ");
         if (ignore) {
             builder.append("OR IGNORE ");
         }
         builder.append("INTO ").append(tablename).append("(");
+        int skipColumn = -1;
         for (int i = 0; i < cursor.getColumnCount(); ++i) {
+            final String name = cursor.getColumnName(i);
+            if (identities && SQLiteAxolotlStore.TRUSTED.equals(name)) {
+                skipColumn = i;
+                continue;
+            }
             if (i != 0) {
                 builder.append(',');
             }
-            builder.append(cursor.getColumnName(i));
+            builder.append(name);
         }
         builder.append(") VALUES");
         for (int i = 0; i < max; ++i) {
             if (i != 0) {
                 builder.append(',');
             }
-            appendValues(cursor, builder);
+            appendValues(cursor, builder, skipColumn);
             if (i < max - 1 && !cursor.moveToNext()) {
                 break;
             }
@@ -173,9 +180,12 @@ public class ExportBackupService extends Service {
         return builder.toString();
     }
 
-    private static void appendValues(Cursor cursor, StringBuilder builder) {
+    private static void appendValues(final Cursor cursor, final StringBuilder builder, final int skipColumn) {
         builder.append("(");
         for (int i = 0; i < cursor.getColumnCount(); ++i) {
+            if (i == skipColumn) {
+                continue;
+            }
             if (i != 0) {
                 builder.append(',');
             }