vim-patch:7.4.1654

Problem:    Crash when using expand('%:S') in a buffer without a name.
Solution:   Don't set a NUL. (James McCoy, closes vim/vim#714)

https://github.com/vim/vim/commit/52c6eaffd43a8c8865f8d6ed7cde0a8b137479e2

3 files changed, 18 insertions, 2 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index fbde845f47..3c67625d1c 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -21995,9 +21995,13 @@ repeat:
   if (src[*usedlen] == ':' && src[*usedlen + 1] == 'S') {
     // vim_strsave_shellescape() needs a NUL terminated string.
     c = (*fnamep)[*fnamelen];
-    (*fnamep)[*fnamelen] = NUL;
+    if (c != NUL) {
+      (*fnamep)[*fnamelen] = NUL;
+    }
     p = vim_strsave_shellescape(*fnamep, false, false);
-    (*fnamep)[*fnamelen] = c;
+    if (c != NUL) {
+      (*fnamep)[*fnamelen] = c;
+    }
     xfree(*bufp);
     *bufp = *fnamep = p;
     *fnamelen = STRLEN(p);
diff --git a/src/nvim/version.c b/src/nvim/version.c
index bab3d1573a..8cd0a13363 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -69,6 +69,7 @@ static char *features[] = {
 
 // clang-format off
 static int included_patches[] = {
+  1654,
   1652,
   1643,
   1641,
diff --git a/test/functional/legacy/fnamemodify_spec.lua b/test/functional/legacy/fnamemodify_spec.lua
index a439e91b6f..2a32aea127 100644
--- a/test/functional/legacy/fnamemodify_spec.lua
+++ b/test/functional/legacy/fnamemodify_spec.lua
@@ -54,6 +54,12 @@ describe('filename modifiers', function()
         set shell=tcsh
         call assert_equal("'abc\\\ndef'", fnamemodify("abc\ndef", ':S'))
       endfunc
+
+      func Test_expand()
+        new
+        call assert_equal("", expand('%:S'))
+        quit
+      endfunc
     ]=])
   end)
 
@@ -61,4 +67,9 @@ describe('filename modifiers', function()
     call('Test_fnamemodify')
     expected_empty()
   end)
+
+  it('works for :S in an unnamed buffer', function()
+    call('Test_expand')
+    expected_empty()
+  end)
 end)