Fix expand-file-name on DOS_NT systems when /: escaping is used

* src/fileio.c (Fexpand_file_name) [DOS_NT]: Don't expand "~" in
file names escaped by "/:".  Don't recursively expand
default-directory escaped with "/:" which is not followed by a
drive spec.  (Bug#25183)

1 files changed, 10 insertions, 1 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 3ba85b2b903..1a744e02e28 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -884,6 +884,11 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
         /* Detect MSDOS file names with drive specifiers.  */
         && ! (IS_DRIVE (o[0]) && IS_DEVICE_SEP (o[1])
               && IS_DIRECTORY_SEP (o[2]))
+        /* Detect escaped file names without drive spec after "/:".
+           These should not be recursively expanded, to avoid
+           including the default directory twice in the expanded
+           result.  */
+        && ! (o[0] == '/' && o[1] == ':')
 #ifdef WINDOWSNT
         /* Detect Windows file names in UNC format.  */
         && ! (IS_DIRECTORY_SEP (o[0]) && IS_DIRECTORY_SEP (o[1]))
@@ -1064,7 +1069,11 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
 
   newdir = newdirlim = 0;
 
-  if (nm[0] == '~')             /* prefix ~ */
+  if (nm[0] == '~'              /* prefix ~ */
+#ifdef DOS_NT
+    && !is_escaped              /* don't expand ~ in escaped file names */
+#endif
+      )
     {
       if (IS_DIRECTORY_SEP (nm[1])
           || nm[1] == 0)        /* ~ by itself */