patch 8.1.0829: when 'hidden' is set session creates extra buffers

Problem:    When 'hidden' is set session creates extra buffers.
Solution:   Move :badd commands to the end. (Jason Franklin)

src/ex_docmd.c

@@ -11280,26 +11280,6 @@ makeopens(
     if (put_line(fd, "set shortmess=aoO") == FAIL)
 	return FAIL;
 
-    /* Now put the other buffers into the buffer list */
-    FOR_ALL_BUFFERS(buf)
-    {
-	if (!(only_save_windows && buf->b_nwindows == 0)
-		&& !(buf->b_help && !(ssop_flags & SSOP_HELP))
-#ifdef FEAT_TERMINAL
-		/* skip terminal buffers: finished ones are not useful, others
-		 * will be resurrected and result in a new buffer */
-		&& !bt_terminal(buf)
-#endif
-		&& buf->b_fname != NULL
-		&& buf->b_p_bl)
-	{
-	    if (fprintf(fd, "badd +%ld ", buf->b_wininfo == NULL ? 1L
-					   : buf->b_wininfo->wi_fpos.lnum) < 0
-		    || ses_fname(fd, buf, &ssop_flags, TRUE) == FAIL)
-		return FAIL;
-	}
-    }
-
     /* the global argument list */
     if (ses_arglist(fd, "argglobal", &global_alist.al_ga,
 			    !(ssop_flags & SSOP_CURDIR), &ssop_flags) == FAIL)
@@ -11515,6 +11495,29 @@ makeopens(
     if (restore_stal && put_line(fd, "set stal=1") == FAIL)
 	return FAIL;
 
+    // Now put the remaining buffers into the buffer list.
+    // This is near the end, so that when 'hidden' is set we don't create extra
+    // buffers.  If the buffer was already created with another command the
+    // ":badd" will have no effect.
+    FOR_ALL_BUFFERS(buf)
+    {
+	if (!(only_save_windows && buf->b_nwindows == 0)
+		&& !(buf->b_help && !(ssop_flags & SSOP_HELP))
+#ifdef FEAT_TERMINAL
+		// Skip terminal buffers: finished ones are not useful, others
+		// will be resurrected and result in a new buffer.
+		&& !bt_terminal(buf)
+#endif
+		&& buf->b_fname != NULL
+		&& buf->b_p_bl)
+	{
+	    if (fprintf(fd, "badd +%ld ", buf->b_wininfo == NULL ? 1L
+					   : buf->b_wininfo->wi_fpos.lnum) < 0
+		    || ses_fname(fd, buf, &ssop_flags, TRUE) == FAIL)
+		return FAIL;
+	}
+    }
+
     /*
      * Wipe out an empty unnamed buffer we started in.
      */

src/testdir/test_mksession.vim

@@ -225,6 +225,29 @@ func Test_mksession_blank_tabs()
   call delete('Xtest_mks.out')
 endfunc
 
+func Test_mksession_buffer_count()
+  set hidden
+
+  " Edit exactly three files in the current session.
+  %bwipe!
+  e Xfoo | tabe Xbar | tabe Xbaz
+  tabdo write
+  mksession! Xtest_mks.out
+
+  " Verify that loading the session does not create additional buffers.
+  %bwipe!
+  source Xtest_mks.out
+  call assert_equal(3, len(getbufinfo()))
+
+  " Clean up.
+  call delete('Xfoo')
+  call delete('Xbar')
+  call delete('Xbaz')
+  call delete('Xtest_mks.out')
+  %bwipe!
+  set hidden&
+endfunc
+
 if has('extra_search')
 
 func Test_mksession_hlsearch()

src/version.c

@@ -783,6 +783,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    829,
 /**/
     828,
 /**/