patch 9.1.0153: Text properties corrupted with fo+=aw and backspace

Problem:  Text properties corrupted with fo+=aw and backspace
Solution: Allocate line and move text properties
          (zeertzjq)

closes: #14147

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/edit.c b/src/edit.c
index d7c80ff..998647c 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -4101,12 +4101,30 @@
 					   && has_format_option(FO_WHITE_PAR))
 		{
 		    char_u  *ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum,
-									TRUE);
-		    int	    len;
+									FALSE);
+		    int	    len = ml_get_curline_len();
 
-		    len = (int)STRLEN(ptr);
 		    if (len > 0 && ptr[len - 1] == ' ')
-			ptr[len - 1] = NUL;
+		    {
+			char_u *newp = alloc(curbuf->b_ml.ml_line_len - 1);
+
+			if (newp != NULL)
+			{
+			    mch_memmove(newp, ptr, len - 1);
+			    newp[len - 1] = NUL;
+			    if (curbuf->b_ml.ml_line_len > len + 1)
+				mch_memmove(newp + len, ptr + len + 1,
+					   curbuf->b_ml.ml_line_len - len - 1);
+
+			    if (curbuf->b_ml.ml_flags
+					      & (ML_LINE_DIRTY | ML_ALLOCATED))
+				vim_free(curbuf->b_ml.ml_line_ptr);
+			    curbuf->b_ml.ml_line_ptr = newp;
+			    curbuf->b_ml.ml_line_len--;
+			    curbuf->b_ml.ml_line_textlen--;
+			    curbuf->b_ml.ml_flags |= ML_LINE_DIRTY;
+			}
+		    }
 		}
 
 		(void)do_join(2, FALSE, FALSE, FALSE, FALSE);
diff --git a/src/testdir/test_comments.vim b/src/testdir/test_comments.vim
index c34b85c..67454f4 100644
--- a/src/testdir/test_comments.vim
+++ b/src/testdir/test_comments.vim
@@ -237,6 +237,12 @@
   call feedkeys("aone\ntwo\n", 'xt')
   call assert_equal(['one', 'two', ''], getline(1, '$'))
 
+  set backspace=indent,eol,start
+  %d
+  call feedkeys("aone \n\<BS>", 'xt')
+  call assert_equal(['one'], getline(1, '$'))
+  set backspace&
+
   close!
 endfunc
 
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index 7542c08..1074b0c 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -4466,4 +4466,23 @@
   bwipe!
 endfunc
 
+" This was causing text property corruption.
+func Test_textprop_backspace_fo_aw()
+  new
+  call setline(1, 'foobar')
+  call prop_type_add('test', {'highlight': 'ErrorMsg'})
+  call prop_add(1, 1, {'type': 'test', 'length': 3})
+  set backspace=indent,eol,start
+  setlocal formatoptions+=aw
+  call feedkeys("A \<CR>\<BS>\<Esc>", 'tx')
+  call assert_equal('foobar', getline(1))
+  call assert_equal([
+        \ #{id: 0, col: 1, start: 1, end: 1, type_bufnr: 0,
+        \   type: 'test', length: 3}], prop_list(1))
+
+  bwipe!
+  set backspace&
+  call prop_type_delete('test')
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index cf0af43..8ada658 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    153,
+/**/
     152,
 /**/
     151,