[gparted] Replace partition boundary trimming with bug error messages (#48)

[Curtis Gedak <gedakc src gnome org>]

commit 1ed8d909fc5c61a120623add13301b88cdf5e94e
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Tue May 21 19:31:31 2019 +0100

    Replace partition boundary trimming with bug error messages (#48)
    
    All the dialogs which compose new or modified partition boundaries
    create those partitions within the boundaries of the device.  Therefore
    trimming the partition boundaries to device boundaries never happens.
    So replace this trimming with bug error reports.
    
    Also add bug prefixes to the other error messages in
    GParted_Core::valid_partition() too.
    
    Closes #48 - Error when moving locked LUKS-encrypted partition

 src/GParted_Core.cc | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)
---
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index 7afbf977..f4709592 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -332,29 +332,43 @@ Glib::ustring GParted_Core::get_thread_status_message( )
 bool GParted_Core::valid_partition(const Device& device, Partition& partition, Glib::ustring& error)
 {
        //Ensure that partition start and end are not beyond the ends of the disk device
-       if ( partition .sector_start < 0 )
-               partition .sector_start = 0 ;
-       if ( partition .sector_end > device .length )
-               partition .sector_end = device .length - 1 ;
+       if (partition.sector_start < 0)
+       {
+               error = GPARTED_BUG + ": " +
+                       Glib::ustring::compose(
+                           /* TO TRANSLATORS: looks like   A partition cannot start (-2048)
+                            * before the start of the device */
+                           _("A partition cannot start (%1) before the start of the device"),
+                           partition.sector_start);
+               return false;
+       }
+       if (partition.sector_end >= device.length)
+       {
+               error = GPARTED_BUG + ": " +
+                       Glib::ustring::compose(
+                               /* TO TRANSLATORS: looks like   A partition cannot end (2099199)
+                                * after the end of the device (2097151) */
+                               _("A partition cannot end (%1) after the end of the device (%2)"),
+                               partition.sector_start);
+               return false;
+       }
 
        //do some basic checks on the partition
        if ( partition .get_sector_length() <= 0 )
        {
-               error = Glib::ustring::compose(
+               error = GPARTED_BUG + ": " +
+                       Glib::ustring::compose(
                                /* TO TRANSLATORS:  looks like   A partition cannot have a length of -1 
sectors */
                                _("A partition cannot have a length of %1 sectors"),
                                partition .get_sector_length() ) ;
                return false ;
        }
 
-       //FIXME: I think that this if condition should be impossible because Partition::set_sector_usage(),
-       //  and ::set_used() and ::Set_Unused() before that, don't allow setting file usage figures to be
-       //  larger than the partition size.  A btrfs file system spanning muiltiple partitions will have
-       //  usage figures larger than any single partition but the figures will won't be set because of
-       //  the above reasoning.  Confirm condition is impossible and consider removing this code.
+       // Check this partition's file system usage is valid.
        if ( partition .get_sector_length() < partition .sectors_used )
        {
-               error = Glib::ustring::compose(
+               error = GPARTED_BUG + ": " +
+                       Glib::ustring::compose(
                                /* TO TRANSLATORS: looks like   A partition with used sectors (2048) greater 
than its length (1536) is not valid */
                                _("A partition with used sectors (%1) greater than its length (%2) is not 
valid"),
                                partition .sectors_used,