fix(api)!: correctly deal with number before :tab

Now nvim_parse_cmd and nvim_create_user_command use a "tab" value which
is the same as the number passed before :tab modifier instead of the
number plus 1, and "tab" value is -1 if :tab modifier is not used.

6 files changed, 54 insertions, 31 deletions

diff --git a/runtime/doc/api.txt b/runtime/doc/api.txt
index 82978d0b3c..a4fe71bc86 100644
--- a/runtime/doc/api.txt
+++ b/runtime/doc/api.txt
@@ -1846,7 +1846,7 @@ nvim_parse_cmd({str}, {opts})                               *nvim_parse_cmd()*
           • keeppatterns: (boolean) |:keeppatterns|.
           • lockmarks: (boolean) |:lockmarks|.
           • noswapfile: (boolean) |:noswapfile|.
-          • tab: (integer) |:tab|.
+          • tab: (integer) |:tab|. -1 when omitted.
           • verbose: (integer) |:verbose|. -1 when omitted.
           • vertical: (boolean) |:vertical|.
           • split: (string) Split modifier string, is an empty string when
diff --git a/runtime/lua/man.lua b/runtime/lua/man.lua
index 4b8239ce74..82ed0305f7 100644
--- a/runtime/lua/man.lua
+++ b/runtime/lua/man.lua
@@ -671,7 +671,7 @@ function M.open_page(count, smods, args)
   local target = ('%s(%s)'):format(name, sect)
 
   local ok, ret = pcall(function()
-    if not smods.tab and find_man() then
+    if smods.tab == -1 and find_man() then
       vim.cmd.tag({ target, mods = { silent = true, keepalt = true } })
     else
       smods.silent = true
diff --git a/src/nvim/api/command.c b/src/nvim/api/command.c
index b821e07d60..11715a49dc 100644
--- a/src/nvim/api/command.c
+++ b/src/nvim/api/command.c
@@ -69,7 +69,7 @@
 ///             - keeppatterns: (boolean) |:keeppatterns|.
 ///             - lockmarks: (boolean) |:lockmarks|.
 ///             - noswapfile: (boolean) |:noswapfile|.
-///             - tab: (integer) |:tab|.
+///             - tab: (integer) |:tab|. -1 when omitted.
 ///             - verbose: (integer) |:verbose|. -1 when omitted.
 ///             - vertical: (boolean) |:vertical|.
 ///             - split: (string) Split modifier string, is an empty string when there's no split
@@ -239,7 +239,7 @@ Dictionary nvim_parse_cmd(String str, Dictionary opts, Error *err)
   PUT(mods, "unsilent", BOOLEAN_OBJ(cmdinfo.cmdmod.cmod_flags & CMOD_UNSILENT));
   PUT(mods, "sandbox", BOOLEAN_OBJ(cmdinfo.cmdmod.cmod_flags & CMOD_SANDBOX));
   PUT(mods, "noautocmd", BOOLEAN_OBJ(cmdinfo.cmdmod.cmod_flags & CMOD_NOAUTOCMD));
-  PUT(mods, "tab", INTEGER_OBJ(cmdinfo.cmdmod.cmod_tab));
+  PUT(mods, "tab", INTEGER_OBJ(cmdinfo.cmdmod.cmod_tab - 1));
   PUT(mods, "verbose", INTEGER_OBJ(cmdinfo.cmdmod.cmod_verbose - 1));
   PUT(mods, "browse", BOOLEAN_OBJ(cmdinfo.cmdmod.cmod_flags & CMOD_BROWSE));
   PUT(mods, "confirm", BOOLEAN_OBJ(cmdinfo.cmdmod.cmod_flags & CMOD_CONFIRM));
@@ -559,15 +559,17 @@ String nvim_cmd(uint64_t channel_id, Dict(cmd) *cmd, Dict(cmd_opts) *opts, Error
     }
 
     if (HAS_KEY(mods.tab)) {
-      if (mods.tab.type != kObjectTypeInteger || mods.tab.data.integer < 0) {
-        VALIDATION_ERROR("'mods.tab' must be a non-negative Integer");
+      if (mods.tab.type != kObjectTypeInteger) {
+        VALIDATION_ERROR("'mods.tab' must be an Integer");
+      } else if ((int)mods.tab.data.integer >= 0) {
+        // Silently ignore negative integers to allow mods.tab to be set to -1.
+        cmdinfo.cmdmod.cmod_tab = (int)mods.tab.data.integer + 1;
       }
-      cmdinfo.cmdmod.cmod_tab = (int)mods.tab.data.integer + 1;
     }
 
     if (HAS_KEY(mods.verbose)) {
       if (mods.verbose.type != kObjectTypeInteger) {
-        VALIDATION_ERROR("'mods.verbose' must be a Integer");
+        VALIDATION_ERROR("'mods.verbose' must be an Integer");
       } else if ((int)mods.verbose.data.integer >= 0) {
         // Silently ignore negative integers to allow mods.verbose to be set to -1.
         cmdinfo.cmdmod.cmod_verbose = (int)mods.verbose.data.integer + 1;
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 2315ecd874..1013cf76f9 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -2082,7 +2082,7 @@ int nlua_do_ucmd(ucmd_T *cmd, exarg_T *eap, bool preview)
 
   lua_newtable(lstate);  // smods table
 
-  lua_pushinteger(lstate, cmdmod.cmod_tab);
+  lua_pushinteger(lstate, cmdmod.cmod_tab - 1);
   lua_setfield(lstate, -2, "tab");
 
   lua_pushinteger(lstate, cmdmod.cmod_verbose - 1);
diff --git a/test/functional/api/command_spec.lua b/test/functional/api/command_spec.lua
index 2d8bf23f5b..44a19d8348 100644
--- a/test/functional/api/command_spec.lua
+++ b/test/functional/api/command_spec.lua
@@ -136,7 +136,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -172,7 +172,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -208,7 +208,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -244,7 +244,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "botright",
-        tab = 0,
+        tab = -1,
         unsilent = true,
         verbose = -1,
         vertical = false,
@@ -280,7 +280,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -316,7 +316,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -364,7 +364,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -401,7 +401,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -448,7 +448,7 @@ describe('nvim_create_user_command', function()
         sandbox = false,
         silent = false,
         split = "",
-        tab = 0,
+        tab = -1,
         unsilent = false,
         verbose = -1,
         vertical = false,
@@ -523,8 +523,29 @@ describe('nvim_create_user_command', function()
         vim.api.nvim_cmd({ cmd = 'echo', args = { '&verbose' }, mods = opts.smods }, {})
       end, {})
     ]]
-
     eq("3", meths.cmd({ cmd = 'MyEcho', mods = { verbose = 3 } }, { output = true }))
+
+    eq(1, #meths.list_tabpages())
+    exec_lua[[
+      vim.api.nvim_create_user_command('MySplit', function(opts)
+        vim.api.nvim_cmd({ cmd = 'split', mods = opts.smods }, {})
+      end, {})
+    ]]
+    meths.cmd({ cmd = 'MySplit' }, {})
+    eq(1, #meths.list_tabpages())
+    eq(2, #meths.list_wins())
+    meths.cmd({ cmd = 'MySplit', mods = { tab = 1 } }, {})
+    eq(2, #meths.list_tabpages())
+    eq(2, funcs.tabpagenr())
+    meths.cmd({ cmd = 'MySplit', mods = { tab = 1 } }, {})
+    eq(3, #meths.list_tabpages())
+    eq(2, funcs.tabpagenr())
+    meths.cmd({ cmd = 'MySplit', mods = { tab = 3 } }, {})
+    eq(4, #meths.list_tabpages())
+    eq(4, funcs.tabpagenr())
+    meths.cmd({ cmd = 'MySplit', mods = { tab = 0 } }, {})
+    eq(5, #meths.list_tabpages())
+    eq(1, funcs.tabpagenr())
   end)
 end)
 
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 2e37c4787d..edbdd54c2f 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -3206,7 +3206,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3248,7 +3248,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3290,7 +3290,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3332,7 +3332,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3374,7 +3374,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3416,7 +3416,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3458,7 +3458,7 @@ describe('API', function()
           sandbox = false,
           silent = true,
           split = "topleft",
-          tab = 2,
+          tab = 1,
           unsilent = false,
           verbose = 15,
           vertical = false,
@@ -3503,7 +3503,7 @@ describe('API', function()
           verbose = 0,
           vertical = false,
         },
-      }, meths.parse_cmd('0verbose unsilent botright confirm filter! /foo/ split foo.txt', {}))
+      }, meths.parse_cmd('0verbose unsilent botright 0tab confirm filter! /foo/ split foo.txt', {}))
     end)
     it('works with user commands', function()
       command('command -bang -nargs=+ -range -addr=lines MyCommand echo foo')
@@ -3541,7 +3541,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3583,7 +3583,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3626,7 +3626,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,
@@ -3719,7 +3719,7 @@ describe('API', function()
           sandbox = false,
           silent = false,
           split = "",
-          tab = 0,
+          tab = -1,
           unsilent = false,
           verbose = -1,
           vertical = false,