vim-patch:8.2.0539: comparing two NULL list fails

Problem:    Comparing two NULL list fails.
Solution:   Change the order of comparing two lists.
https://github.com/vim/vim/commit/7b293c730b07d1586688e622b8d9cbbb4a52379b

N/A patches for version.c:

vim-patch:8.2.1187: terminal2 test sometimes hangs in the GUI on Travis

Problem:    Terminal2 test sometimes hangs in the GUI on Travis.
Solution:   Disable Test_zz2_terminal_guioptions_bang() for now.
https://github.com/vim/vim/commit/c85156bb897085d7f5a8e4e180287f87bf19b948

vim-patch:8.2.1188: memory leak with invalid json input

Problem:    Memory leak with invalid json input.
Solution:   Free all keys at the end. (Dominique Pellé, closes vim/vim#6443,
            closes vim/vim#6442)
https://github.com/vim/vim/commit/6d3a7213f58da834b0fc869d05f87e86010c66cf

vim-patch:8.2.1196: build failure with normal features

Problem:    Build failure with normal features.
Solution:   Add #ifdef.
https://github.com/vim/vim/commit/83e7450053399942e1c9efa802c568b51d948541

vim-patch:8.2.1198: terminal2 test sometimes hangs in the GUI on Travis

Problem:    Terminal2 test sometimes hangs in the GUI on Travis.
Solution:   Move test function to terminal3 to see if the problem moves too.
https://github.com/vim/vim/commit/a4b442614c5ca4ebf32acf5cf0b7b718496f1c94

4 files changed, 23 insertions, 18 deletions

diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 89ca2db59b..2394eb8099 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -799,10 +799,14 @@ bool tv_list_equal(list_T *const l1, list_T *const l2, const bool ic,
   if (l1 == l2) {
     return true;
   }
-  if (l1 == NULL || l2 == NULL) {
+  if (tv_list_len(l1) != tv_list_len(l2)) {
     return false;
   }
-  if (tv_list_len(l1) != tv_list_len(l2)) {
+  if (tv_list_len(l1) == 0) {
+    // empty and NULL list are considered equal
+    return true;
+  }
+  if (l1 == NULL || l2 == NULL) {
     return false;
   }
 
diff --git a/test/functional/eval/null_spec.lua b/test/functional/eval/null_spec.lua
index afe999e1fa..db0a706319 100644
--- a/test/functional/eval/null_spec.lua
+++ b/test/functional/eval/null_spec.lua
@@ -47,10 +47,8 @@ describe('NULL', function()
 
     -- Subjectable behaviour
 
-    -- FIXME Should return 1
-    null_expr_test('is equal to empty list', 'L == []', 0, 0)
-    -- FIXME Should return 1
-    null_expr_test('is equal to empty list (reverse order)', '[] == L', 0, 0)
+    null_expr_test('is equal to empty list', 'L == []', 0, 1)
+    null_expr_test('is equal to empty list (reverse order)', '[] == L', 0, 1)
 
     -- Correct behaviour
     null_expr_test('can be indexed with error message for empty list', 'L[0]',
diff --git a/test/functional/legacy/assert_spec.lua b/test/functional/legacy/assert_spec.lua
index dd7810bf51..d48b8882af 100644
--- a/test/functional/legacy/assert_spec.lua
+++ b/test/functional/legacy/assert_spec.lua
@@ -38,6 +38,9 @@ describe('assert function:', function()
         call assert_equal(4, n)
         let l = [1, 2, 3]
         call assert_equal([1, 2, 3], l)
+        call assert_equal(v:_null_list, v:_null_list)
+        call assert_equal(v:_null_list, [])
+        call assert_equal([], v:_null_list)
         fu Func()
         endfu
         let F1 = function('Func')
diff --git a/test/unit/eval/typval_spec.lua b/test/unit/eval/typval_spec.lua
index 06465071c5..7c03005529 100644
--- a/test/unit/eval/typval_spec.lua
+++ b/test/unit/eval/typval_spec.lua
@@ -1234,13 +1234,13 @@ describe('typval.c', function()
         local l = list()
         local l2 = list()
 
-        -- NULL lists are not equal to empty lists
-        eq(false, lib.tv_list_equal(l, nil, true, false))
-        eq(false, lib.tv_list_equal(nil, l, false, false))
-        eq(false, lib.tv_list_equal(nil, l, false, true))
-        eq(false, lib.tv_list_equal(l, nil, true, true))
+        -- NULL lists are equal to empty lists
+        eq(true, lib.tv_list_equal(l, nil, true, false))
+        eq(true, lib.tv_list_equal(nil, l, false, false))
+        eq(true, lib.tv_list_equal(nil, l, false, true))
+        eq(true, lib.tv_list_equal(l, nil, true, true))
 
-        -- Yet NULL lists are equal themselves
+        -- NULL lists are equal themselves
         eq(true, lib.tv_list_equal(nil, nil, true, false))
         eq(true, lib.tv_list_equal(nil, nil, false, false))
         eq(true, lib.tv_list_equal(nil, nil, false, true))
@@ -2648,13 +2648,13 @@ describe('typval.c', function()
         local l2 = lua2typvalt(empty_list)
         local nl = lua2typvalt(null_list)
 
-        -- NULL lists are not equal to empty lists
-        eq(false, lib.tv_equal(l, nl, true, false))
-        eq(false, lib.tv_equal(nl, l, false, false))
-        eq(false, lib.tv_equal(nl, l, false, true))
-        eq(false, lib.tv_equal(l, nl, true, true))
+        -- NULL lists are equal to empty lists
+        eq(true, lib.tv_equal(l, nl, true, false))
+        eq(true, lib.tv_equal(nl, l, false, false))
+        eq(true, lib.tv_equal(nl, l, false, true))
+        eq(true, lib.tv_equal(l, nl, true, true))
 
-        -- Yet NULL lists are equal themselves
+        -- NULL lists are equal themselves
         eq(true, lib.tv_equal(nl, nl, true, false))
         eq(true, lib.tv_equal(nl, nl, false, false))
         eq(true, lib.tv_equal(nl, nl, false, true))