Re: PSPP-BUG: [GUI] PSPPire closes unexpectedly when entering text with a length greater than 80 bytes (Utilities | Data File comments)

[John Darrington]

If, as you say, those lines are unnecessary, then please apply the patch that 
you posted.

J'


On Sun, Oct 06, 2013 at 09:40:22AM -0700, Ben Pfaff wrote:
     On Sun, Oct 06, 2013 at 06:28:14PM +0200, John Darrington wrote:
     > I don't seem to be able to reproduce this crash.
     > 
     > It looks as if the code you deleted was designed to move the cursor to 
the end of the text,
     > after something has been pasted.  Which is probably what the user wants. 
 
     
     I don't think this is necessary, because GtkTextView maintains its
     cursor as a mark.  Inserting a newline in its buffer prior to the cursor
     will push along onto the next line anyway, without extra help.
     
     > I don't know why is is crashing.  Does it fix the problem if you call  
gtk_text_buffer_place_cursor
     > only if gtk_text_iter_forward_to_line_end returns TRUE ?
     
     The problem is that the GtkTextIter gets invalidated by the
     gtk_text_buffer_insert() call.  On my system, at least, I get a
     Gtk-WARNING about this:
     
         (psppire:13161): Gtk-WARNING **: Invalid text buffer iterator: either 
the iterator is uninitialized, or the characters/pixbufs/widgets in the buffer 
have been modified since the iterator was created.
         You must use marks, character numbers, or line numbers to preserve a 
position across buffer modifications.
         You can apply tags and insert marks without invalidating your 
iterators,
         but any mutation that affects 'indexable' buffer contents (contents 
that can be referred to by character offset)
         will invalidate all outstanding iterators
     
     Running under valgrind shows a subsequent bad memory access that I
     imagine to be related to the previous warning:
     
         Invalid read of size 4
            at 0x44C9B4F: gtk_text_iter_make_real (gtktextiter.c:202)
            by 0x44CB9CC: gtk_text_iter_forward_line (gtktextiter.c:2490)
            by 0x44CBF0F: gtk_text_iter_forward_to_line_end (gtktextiter.c:4052)
            by 0x808B902: wrap_line (comments-dialog.c:84)
            by 0x4416777: _gtk_marshal_VOID__BOXED_STRING_INT 
(gtkmarshalers.c:1425)
            by 0x4C12DC1: g_closure_invoke (gclosure.c:777)
            by 0x4C24C95: signal_emit_unlocked_R (gsignal.c:3621)
            by 0x4C2CB55: g_signal_emit_valist (gsignal.c:3300)
            by 0x4C2CCD2: g_signal_emit (gsignal.c:3356)
            by 0xD9E75B7: ???
          Address 0x1c is not stack'd, malloc'd or (recently) free'd
     
     
         Process terminating with default action of signal 11 (SIGSEGV): 
dumping core
          Access not within mapped region at address 0x1C
            at 0x44C9B4F: gtk_text_iter_make_real (gtktextiter.c:202)
            by 0x44CB9CC: gtk_text_iter_forward_line (gtktextiter.c:2490)
            by 0x44CBF0F: gtk_text_iter_forward_to_line_end (gtktextiter.c:4052)
            by 0x808B902: wrap_line (comments-dialog.c:84)
            by 0x4416777: _gtk_marshal_VOID__BOXED_STRING_INT 
(gtkmarshalers.c:1425)
            by 0x4C12DC1: g_closure_invoke (gclosure.c:777)
            by 0x4C24C95: signal_emit_unlocked_R (gsignal.c:3621)
            by 0x4C2CB55: g_signal_emit_valist (gsignal.c:3300)
            by 0x4C2CCD2: g_signal_emit (gsignal.c:3356)
            by 0xD9E75B7: ???
     
     The patch I provided avoids the warning and the bad memory accesses.

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