patch 9.1.1317: noisy error when restoring folds from session fails

Problem:  noisy error when restoring folds from session fails
Solution: ignore errors silently when sourcing session file.
          (Igor Lacerda)

fixes: #15813
closes: #17127

Signed-off-by: Igor Lacerda <igorlfs@ufmg.br>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/fold.c

@@ -3576,7 +3576,7 @@ put_folds_recurse(FILE *fd, garray_T *gap, linenr_T off)
 	// Do nested folds first, they will be created closed.
 	if (put_folds_recurse(fd, &fp->fd_nested, off + fp->fd_top) == FAIL)
 	    return FAIL;
-	if (fprintf(fd, "%ld,%ldfold", fp->fd_top + off,
+	if (fprintf(fd, "sil! %ld,%ldfold", fp->fd_top + off,
 					fp->fd_top + off + fp->fd_len - 1) < 0
 		|| put_eol(fd) == FAIL)
 	    return FAIL;
@@ -3609,9 +3609,10 @@ put_foldopen_recurse(
 	    if (fp->fd_nested.ga_len > 0)
 	    {
 		// open nested folds while this fold is open
+		// ignore errors
 		if (fprintf(fd, "%ld", fp->fd_top + off) < 0
 			|| put_eol(fd) == FAIL
-			|| put_line(fd, "normal! zo") == FAIL)
+			|| put_line(fd, "sil! normal! zo") == FAIL)
 		    return FAIL;
 		if (put_foldopen_recurse(fd, wp, &fp->fd_nested,
 							     off + fp->fd_top)
@@ -3652,7 +3653,7 @@ put_fold_open_close(FILE *fd, fold_T *fp, linenr_T off)
 {
     if (fprintf(fd, "%ld", fp->fd_top + off) < 0
 	    || put_eol(fd) == FAIL
-	    || fprintf(fd, "normal! z%c",
+	    || fprintf(fd, "sil! normal! z%c",
 			   fp->fd_flags == FD_CLOSED ? 'c' : 'o') < 0
 	    || put_eol(fd) == FAIL)
 	return FAIL;

src/testdir/test_mksession.vim

@@ -1264,6 +1264,24 @@ func Test_mkview_manual_fold()
   bw!
 endfunc
 
+" Test for handling invalid folds within views
+func Test_mkview_ignore_invalid_folds()
+  call writefile(range(1,10), 'Xmkvfile', 'D')
+  new Xmkvfile
+  " create some folds
+  5,6fold
+  4,7fold
+  mkview Xview
+  normal zE
+  " delete lines to make folds invalid
+  call deletebufline('', 6, '$')
+  source Xview
+  call assert_equal([-1, -1, -1, -1, -1, -1], [foldclosed(3), foldclosed(4),
+        \ foldclosed(5), foldclosed(6), foldclosed(7), foldclosed(8)])
+  call delete('Xview')
+  bw!
+endfunc
+
 " Test default 'viewdir' value
 func Test_mkview_default_home()
   if has('win32')

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1317,
 /**/
     1316,
 /**/