api: change nvim_command_output behavior

Implement nvim_command_output with `execute({cmd},"silent")`.

Behavior changes:
- does not provoke any hit-enter prompt
- no longer prepends a newline char
- does not capture some noise (like the "[New File]" message, see the
  change to tabnewentered_spec.lua)

Technically ("bug-for-bug") this a breaking change.  But the previous
behavior of nvim_command_output meant that it probably wasn't used for
anything outside of tests.

Also remove the undocumented `v:command_output` variable which was
a hack introduced only for the purposes of nvim_command_output.

closes #7726

2 files changed, 13 insertions, 13 deletions

diff --git a/test/functional/autocmd/tabclose_spec.lua b/test/functional/autocmd/tabclose_spec.lua
index fb777e7eea..b7c33dc3d8 100644
--- a/test/functional/autocmd/tabclose_spec.lua
+++ b/test/functional/autocmd/tabclose_spec.lua
@@ -11,10 +11,10 @@ describe('TabClosed', function()
         repeat
           nvim('command', 'tabnew')
         until nvim('eval', 'tabpagenr()') == 6 -- current tab is now 6
-        eq("\ntabclosed:6:6:5", nvim('command_output', 'tabclose')) -- close last 6, current tab is now 5
-        eq("\ntabclosed:5:5:4", nvim('command_output', 'close')) -- close last window on tab, closes tab
-        eq("\ntabclosed:2:2:3", nvim('command_output', '2tabclose')) -- close tab 2, current tab is now 3
-        eq("\ntabclosed:1:1:2\ntabclosed:1:1:1", nvim('command_output', 'tabonly')) -- close tabs 1 and 2
+        eq("tabclosed:6:6:5", nvim('command_output', 'tabclose')) -- close last 6, current tab is now 5
+        eq("tabclosed:5:5:4", nvim('command_output', 'close')) -- close last window on tab, closes tab
+        eq("tabclosed:2:2:3", nvim('command_output', '2tabclose')) -- close tab 2, current tab is now 3
+        eq("tabclosed:1:1:2\ntabclosed:1:1:1", nvim('command_output', 'tabonly')) -- close tabs 1 and 2
       end)
 
       it('is triggered when closing a window via bdelete from another tab', function()
@@ -23,7 +23,7 @@ describe('TabClosed', function()
         nvim('command', '1tabedit Xtestfile')
         nvim('command', 'normal! 1gt')
         eq({1, 3}, nvim('eval', '[tabpagenr(), tabpagenr("$")]'))
-        eq("\ntabclosed:2:2:1\ntabclosed:2:2:1", nvim('command_output', 'bdelete Xtestfile'))
+        eq("tabclosed:2:2:1\ntabclosed:2:2:1", nvim('command_output', 'bdelete Xtestfile'))
         eq({1, 1}, nvim('eval', '[tabpagenr(), tabpagenr("$")]'))
       end)
 
@@ -35,7 +35,7 @@ describe('TabClosed', function()
 
         -- Only one tab is closed, and the alternate file is used for the other.
         eq({2, 3}, nvim('eval', '[tabpagenr(), tabpagenr("$")]'))
-        eq("\ntabclosed:2:2:2", nvim('command_output', 'bdelete Xtestfile2'))
+        eq("tabclosed:2:2:2", nvim('command_output', 'bdelete Xtestfile2'))
         eq('Xtestfile1', nvim('eval', 'bufname("")'))
       end)
     end)
@@ -48,9 +48,9 @@ describe('TabClosed', function()
           nvim('command',  'tabnew')
         until nvim('eval', 'tabpagenr()') == 7 -- current tab is now 7
         -- sanity check, we shouldn't match on tabs with numbers other than 2
-        eq("\ntabclosed:7:7:6", nvim('command_output', 'tabclose'))
+        eq("tabclosed:7:7:6", nvim('command_output', 'tabclose'))
         -- close tab page 2, current tab is now 5
-        eq("\ntabclosed:2:2:5\ntabclosed:match", nvim('command_output', '2tabclose'))
+        eq("tabclosed:2:2:5\ntabclosed:match", nvim('command_output', '2tabclose'))
       end)
     end)
 
@@ -59,7 +59,7 @@ describe('TabClosed', function()
         nvim('command', 'au! TabClosed * echom "tabclosed:".expand("<afile>").":".expand("<amatch>").":".tabpagenr()')
         nvim('command',  'tabedit Xtestfile')
         eq({2, 2}, nvim('eval', '[tabpagenr(), tabpagenr("$")]'))
-        eq("\ntabclosed:2:2:1", nvim('command_output', 'close'))
+        eq("tabclosed:2:2:1", nvim('command_output', 'close'))
         eq({1, 1}, nvim('eval', '[tabpagenr(), tabpagenr("$")]'))
       end)
     end)
diff --git a/test/functional/autocmd/tabnewentered_spec.lua b/test/functional/autocmd/tabnewentered_spec.lua
index bdbe677132..59cac07b34 100644
--- a/test/functional/autocmd/tabnewentered_spec.lua
+++ b/test/functional/autocmd/tabnewentered_spec.lua
@@ -7,14 +7,14 @@ describe('TabNewEntered', function()
       it('matches when entering any new tab', function()
         clear()
         nvim('command', 'au! TabNewEntered * echom "tabnewentered:".tabpagenr().":".bufnr("")')
-        eq("\ntabnewentered:2:2", nvim('command_output', 'tabnew'))
-        eq("\n\"test.x2\" [New File]\ntabnewentered:3:3", nvim('command_output', 'tabnew test.x2'))
+        eq("tabnewentered:2:2", nvim('command_output', 'tabnew'))
+        eq("tabnewentered:3:3", nvim('command_output', 'tabnew test.x2'))
      end)
     end)
     describe('with FILE as <afile>', function()
       it('matches when opening a new tab for FILE', function()
         nvim('command', 'au! TabNewEntered Xtest-tabnewentered echom "tabnewentered:match"')
-        eq('\n"Xtest-tabnewentered" [New File]\ntabnewentered:4:4\ntabnewentered:match',
+        eq('tabnewentered:4:4\ntabnewentered:match',
           nvim('command_output', 'tabnew Xtest-tabnewentered'))
      end)
     end)
@@ -24,7 +24,7 @@ describe('TabNewEntered', function()
         nvim('command', 'au! TabNewEntered * echom "entered"')
         nvim('command', 'tabnew test.x2')
         nvim('command', 'split')
-        eq('\nentered', nvim('command_output', 'execute "normal \\<C-W>T"'))
+        eq('entered', nvim('command_output', 'execute "normal \\<C-W>T"'))
       end)
     end)
   end)