commit 3d6014f0336d9a64c01a7518fe45fde0a925fa20
author Bram Moolenaar <Bram@vim.org> Thu Oct 11 19:27:47 2018 +0200
committer Bram Moolenaar <Bram@vim.org> Thu Oct 11 19:27:47 2018 +0200
tree 7961f41f09ee54c2c240abac007ab9779709bb13
parent 108e7b422b7b59153dd5af1fb75e83fa36ff3db4

patch 8.1.0470: pointer ownership around fname_expand() is unclear

Problem:    Pointer ownership around fname_expand() is unclear.
Solution:   Allow b_ffname and b_sfname to point to the same allocated memory,
            only free one.  Update comments.

src/fileio.c

diff --git a/src/fileio.c b/src/fileio.c
index 90f8517..4380067 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -6187,7 +6187,8 @@
 		|| buf->b_sfname == NULL
 		|| mch_isFullName(buf->b_sfname)))
     {
-	VIM_CLEAR(buf->b_sfname);
+	if (buf->b_sfname != buf->b_ffname)
+	    VIM_CLEAR(buf->b_sfname);
 	p = shorten_fname(buf->b_ffname, dirname);
 	if (p != NULL)
 	{