# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1602793804 -7200
# Node ID f140b9036aa5d00faf0bdee19d578f0683fbbc3d
# Parent  95b74784c03704327f8a96b60978d6d84811287b
patch 8.2.1852: map() returing zero for NULL list is unexpected

Commit: https://github.com/vim/vim/commit/ffdf8adfa8108d4765fdc68abbd2fe49a4292b25
Author: Bram Moolenaar <Bram@vim.org>
Date:   Thu Oct 15 22:29:17 2020 +0200

    patch 8.2.1852: map() returing zero for NULL list is unexpected

    Problem:    map() returing zero for NULL list is unexpected.
    Solution:   Return the empty list. (closes https://github.com/vim/vim/issues/7133)

diff --git a/src/list.c b/src/list.c
--- a/src/list.c
+++ b/src/list.c
@@ -1961,6 +1961,9 @@ filter_map(typval_T *argvars, typval_T *
     int		save_did_emsg;
     int		idx = 0;
 
+    // Always return the first argument, also on failure.
+    copy_tv(&argvars[0], rettv);
+
     if (argvars[0].v_type == VAR_BLOB)
     {
 	if ((b = argvars[0].vval.v_blob) == NULL)
@@ -2110,8 +2113,6 @@ filter_map(typval_T *argvars, typval_T *
 
 	did_emsg |= save_did_emsg;
     }
-
-    copy_tv(&argvars[0], rettv);
 }
 
 /*
diff --git a/src/testdir/test_blob.vim b/src/testdir/test_blob.vim
--- a/src/testdir/test_blob.vim
+++ b/src/testdir/test_blob.vim
@@ -271,6 +271,7 @@ endfunc
 
 " filter() item in blob
 func Test_blob_filter()
+  call assert_equal(test_null_blob(), filter(test_null_blob(), '0'))
   call assert_equal(0z, filter(0zDEADBEEF, '0'))
   call assert_equal(0zADBEEF, filter(0zDEADBEEF, 'v:val != 0xDE'))
   call assert_equal(0zDEADEF, filter(0zDEADBEEF, 'v:val != 0xBE'))
diff --git a/src/testdir/test_filter_map.vim b/src/testdir/test_filter_map.vim
--- a/src/testdir/test_filter_map.vim
+++ b/src/testdir/test_filter_map.vim
@@ -98,10 +98,10 @@ func Test_map_filter_fails()
   call assert_fails("let l = filter([1, 2, 3], '{}')", 'E728:')
   call assert_fails("let l = filter({'k' : 10}, '{}')", 'E728:')
   call assert_fails("let l = filter([1, 2], {})", 'E731:')
-  call assert_equal(0, filter(test_null_list(), 0))
-  call assert_equal(0, filter(test_null_dict(), 0))
-  call assert_equal(0, map(test_null_list(), '"> " .. v:val'))
-  call assert_equal(0, map(test_null_dict(), '"> " .. v:val'))
+  call assert_equal(test_null_list(), filter(test_null_list(), 0))
+  call assert_equal(test_null_dict(), filter(test_null_dict(), 0))
+  call assert_equal(test_null_list(), map(test_null_list(), '"> " .. v:val'))
+  call assert_equal(test_null_dict(), map(test_null_dict(), '"> " .. v:val'))
   call assert_equal([1, 2, 3], filter([1, 2, 3], test_null_function()))
   call assert_fails("let l = filter([1, 2], function('min'))", 'E118:')
   call assert_equal([1, 2, 3], filter([1, 2, 3], test_null_partial()))
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1852,
+/**/
     1851,
 /**/
     1850,