From 211a5bb2353c66684f38527184a258921f95c9d9 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Thu, 28 Apr 2022 19:09:03 +0100
Subject: [PATCH] patch 8.2.4842: expand("%:p") is not empty when there is no
 buffer name

Problem:    expand("%:p") is not empty when there is no buffer name.
Solution:   When ignoring errors still return NULL. (closes #10311)
---
 src/ex_docmd.c                   | 13 ++++++++-----
 src/testdir/test_expand_func.vim |  3 ++-
 src/version.c                    |  2 ++
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 226435003d..f78e4edf25 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -9349,12 +9349,15 @@ eval_vars(
 	}
     }
 
-    if (empty_is_error && (resultlen == 0 || valid != VALID_HEAD + VALID_PATH))
+    if (resultlen == 0 || valid != VALID_HEAD + VALID_PATH)
     {
-	if (valid != VALID_HEAD + VALID_PATH)
-	    *errormsg = _(e_empty_file_name_for_percent_or_hash_only_works_with_ph);
-	else
-	    *errormsg = _(e_evaluates_to_an_empty_string);
+	if (empty_is_error)
+	{
+	    if (valid != VALID_HEAD + VALID_PATH)
+		*errormsg = _(e_empty_file_name_for_percent_or_hash_only_works_with_ph);
+	    else
+		*errormsg = _(e_evaluates_to_an_empty_string);
+	}
 	result = NULL;
     }
     else
diff --git a/src/testdir/test_expand_func.vim b/src/testdir/test_expand_func.vim
index 59156afe32..d9327bf3e5 100644
--- a/src/testdir/test_expand_func.vim
+++ b/src/testdir/test_expand_func.vim
@@ -82,7 +82,7 @@ endfunc
 
 func Test_expand()
   new
-  call assert_equal("''", expand('%:S'))
+  call assert_equal("", expand('%:S'))
   call assert_equal('3', '<slnum>'->expand())
   call assert_equal(['4'], expand('<slnum>', v:false, v:true))
   " Don't add any line above this, otherwise <slnum> will change.
@@ -90,6 +90,7 @@ func Test_expand()
   set verbose=1
   call assert_equal("", expand('%'))
   set verbose=0
+  call assert_equal("", expand('%:p'))
   quit
 endfunc
 
diff --git a/src/version.c b/src/version.c
index 31306fb1a4..0d95a7cac4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4842,
 /**/
     4841,
 /**/