vim-patch:7.4.834

Problem:    gettabvar() doesn't work after Vim start. (Szymon Wrozynski)
Solution:   Handle first window in tab still being NULL. (Christian Brabandt)

https://github.com/vim/vim/commit/7e47d1ac6a9ae0e5a7167aa34ff651a9c39c1641

3 files changed, 10 insertions, 4 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 7ca1f1512e..b9b913a969 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -10593,9 +10593,10 @@ static void f_gettabvar(typval_T *argvars, typval_T *rettv)
   varname = get_tv_string_chk(&argvars[1]);
   tp = find_tabpage((int)get_tv_number_chk(&argvars[0], NULL));
   if (tp != NULL && varname != NULL) {
-    /* Set tp to be our tabpage, temporarily.  Also set the window to the
-     * first window in the tabpage, otherwise the window is not valid. */
-    if (switch_win(&oldcurwin, &oldtabpage, tp->tp_firstwin, tp, TRUE) == OK) {
+    // Set tp to be our tabpage, temporarily.  Also set the window to the
+    // first window in the tabpage, otherwise the window is not valid.
+    win_T *window = tp->tp_firstwin == NULL ? firstwin : tp->tp_firstwin;
+    if (switch_win(&oldcurwin, &oldtabpage, window, tp, true) == OK) {
       // look up the variable
       // Let gettabvar({nr}, "") return the "t:" dictionary.
       v = find_var_in_ht(&tp->tp_vars->dv_hashtab, 't', varname, FALSE);
diff --git a/src/nvim/version.c b/src/nvim/version.c
index b9edea271e..269f9872d0 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -454,7 +454,7 @@ static int included_patches[] = {
   // 837 NA
   836,
   // 835,
-  // 834,
+  834,
   // 833,
   // 832,
   // 831,
diff --git a/test/functional/legacy/091_context_variables_spec.lua b/test/functional/legacy/091_context_variables_spec.lua
index ffeb0c657e..2c46ef643c 100644
--- a/test/functional/legacy/091_context_variables_spec.lua
+++ b/test/functional/legacy/091_context_variables_spec.lua
@@ -13,6 +13,9 @@ describe('context variables', function()
     -- Test for getbufvar().
     -- Use strings to test for memory leaks.
     source([[
+      let t:testvar='abcd'
+      $put =string(gettabvar(1, 'testvar'))
+      $put =string(gettabvar(1, 'testvar'))
       let b:var_num = '1234'
       let def_num = '5678'
       $put =string(getbufvar(1, 'var_num'))
@@ -125,6 +128,8 @@ describe('context variables', function()
     -- Assert buffer contents.
     expect([[
       start:
+      'abcd'
+      'abcd'
       '1234'
       '1234'
       {'var_num': '1234'}