patch 8.1.0470: pointer ownership around fname_expand() is unclearv8.1.0470

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.

1 files changed, 6 insertions, 4 deletions

diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 0a5387c52b..7512785c9b 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -3648,8 +3648,8 @@ check_readonly(int *forceit, buf_T *buf)
 }
 
 /*
- * Try to abandon current file and edit a new or existing file.
- * "fnum" is the number of the file, if zero use ffname/sfname.
+ * Try to abandon the current file and edit a new or existing file.
+ * "fnum" is the number of the file, if zero use "ffname_arg"/"sfname_arg".
  * "lnum" is the line number for the cursor in the new file (if non-zero).
  *
  * Return:
@@ -3661,12 +3661,14 @@ check_readonly(int *forceit, buf_T *buf)
     int
 getfile(
     int		fnum,
-    char_u	*ffname,
-    char_u	*sfname,
+    char_u	*ffname_arg,
+    char_u	*sfname_arg,
     int		setpm,
     linenr_T	lnum,
     int		forceit)
 {
+    char_u	*ffname = ffname_arg;
+    char_u	*sfname = sfname_arg;
     int		other;
     int		retval;
     char_u	*free_me = NULL;