Merge #7821 'api: nvim_command_output'

10 files changed, 185 insertions, 51 deletions

diff --git a/src/nvim/README.md b/src/nvim/README.md
index da87a0208e..1ece92e44d 100644
--- a/src/nvim/README.md
+++ b/src/nvim/README.md
@@ -1,10 +1,22 @@
-Nvim core source
-================
+Nvim core
+=========
 
 Module-specific details are documented at the top of each module (`terminal.c`,
-`screen.c`, ...).
+`screen.c`, …).
 
-See `:help development` for more guidelines.
+See `:help dev` for guidelines.
+
+Filename conventions
+--------------------
+
+The source files use extensions to hint about their purpose.
+
+- `*.c`, `*.generated.c` - full C files, with all includes, etc.
+- `*.c.h` - parametrized C files, contain all necessary includes, but require
+  defining macros before actually using. Example: `typval_encode.c.h`
+- `*.h` - full headers, with all includes. Does *not* apply to `*.generated.h`.
+- `*.h.generated.h` - exported functions’ declarations.
+- `*.c.generated.h` - static functions’ declarations.
 
 Logs
 ----
@@ -20,17 +32,36 @@ UI events are logged at level 0 (`DEBUG_LOG_LEVEL`).
     rm -rf build/
     make CMAKE_EXTRA_FLAGS="-DMIN_LOG_LEVEL=0"
 
-Filename conventions
---------------------
+Build with ASAN
+---------------
 
-The source files use extensions to hint about their purpose.
+Building Nvim with Clang sanitizers (Address Sanitizer: ASan, Undefined
+Behavior Sanitizer: UBSan, Memory Sanitizer: MSan, Thread Sanitizer: TSan) is
+a good way to catch undefined behavior, leaks and other errors as soon as they
+happen.  It's significantly faster than Valgrind.
 
-- `*.c`, `*.generated.c` - full C files, with all includes, etc.
-- `*.c.h` - parametrized C files, contain all necessary includes, but require
-  defining macros before actually using. Example: `typval_encode.c.h`
-- `*.h` - full headers, with all includes. Does *not* apply to `*.generated.h`.
-- `*.h.generated.h` - exported functions’ declarations.
-- `*.c.generated.h` - static functions’ declarations.
+Requires clang 3.4 or later:
+
+    clang --version
+
+Build Nvim with sanitizer instrumentation:
+
+    CC=clang make CMAKE_EXTRA_FLAGS="-DCLANG_ASAN_UBSAN=ON"
+
+Create a directory to store logs:
+
+    mkdir -p "$HOME/logs"
+
+Enable the sanitizer(s) via these environment variables:
+
+    # Change to detect_leaks=1 to detect memory leaks (slower).
+    export ASAN_OPTIONS="detect_leaks=0:log_path=$HOME/logs/asan"
+    export ASAN_SYMBOLIZER_PATH=/usr/lib/llvm-5.0/bin/llvm-symbolizer
+
+    export MSAN_SYMBOLIZER_PATH=/usr/lib/llvm-5.0/bin/llvm-symbolizer
+    export TSAN_OPTIONS="external_symbolizer_path=/usr/lib/llvm-5.0/bin/llvm-symbolizer log_path=${HOME}/logs/tsan"
+
+Logs will be written to `${HOME}/logs/*san.PID`.
 
 TUI debugging
 -------------
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 172f2ce18e..0e7cc428d4 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -43,14 +43,15 @@
 #endif
 
 /// Executes an ex-command.
-/// On VimL error: Returns the VimL error; v:errmsg is not updated.
+///
+/// On parse error: forwards the Vim error; does not update v:errmsg.
+/// On runtime error: forwards the Vim error; does not update v:errmsg.
 ///
 /// @param command  Ex-command string
-/// @param[out] err Error details (including actual VimL error), if any
+/// @param[out] err Error details (Vim error), if any
 void nvim_command(String command, Error *err)
   FUNC_API_SINCE(1)
 {
-  // Run the command
   try_start();
   do_cmdline_cmd(command.data);
   update_screen(VALID);
@@ -207,18 +208,49 @@ String nvim_replace_termcodes(String str, Boolean from_part, Boolean do_lt,
   return cstr_as_string(ptr);
 }
 
-String nvim_command_output(String str, Error *err)
+/// Executes an ex-command and returns its (non-error) output.
+/// Shell |:!| output is not captured.
+///
+/// On parse error: forwards the Vim error; does not update v:errmsg.
+/// On runtime error: forwards the Vim error; does not update v:errmsg.
+///
+/// @param command  Ex-command string
+/// @param[out] err Error details (Vim error), if any
+String nvim_command_output(String command, Error *err)
   FUNC_API_SINCE(1)
 {
-  do_cmdline_cmd("redir => v:command_output");
-  nvim_command(str, err);
-  do_cmdline_cmd("redir END");
+  const int save_msg_silent = msg_silent;
+  garray_T *const save_capture_ga = capture_ga;
+  garray_T capture_local;
+  ga_init(&capture_local, 1, 80);
+
+  try_start();
+  msg_silent++;
+  capture_ga = &capture_local;
+  do_cmdline_cmd(command.data);
+  capture_ga = save_capture_ga;
+  msg_silent = save_msg_silent;
+  try_end(err);
 
   if (ERROR_SET(err)) {
-    return (String)STRING_INIT;
+    goto theend;
+  }
+
+  if (capture_local.ga_len > 1) {
+    // redir always(?) prepends a newline; remove it.
+    char *s = capture_local.ga_data;
+    assert(s[0] == '\n');
+    memmove(s, s + 1, (size_t)capture_local.ga_len);
+    s[capture_local.ga_len - 1] = '\0';
+    return (String) {  // Caller will free the memory.
+      .data = s,
+      .size = (size_t)(capture_local.ga_len - 1),
+    };
   }
 
-  return cstr_to_string((char *)get_vim_var_str(VV_COMMAND_OUTPUT));
+theend:
+  ga_clear(&capture_local);
+  return (String)STRING_INIT;
 }
 
 /// Evaluates a VimL expression (:help expression).
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index f34b6db8d8..2e8bf18f2d 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -402,7 +402,6 @@ static struct vimvar {
   VV(VV_OLDFILES,       "oldfiles",         VAR_LIST, 0),
   VV(VV_WINDOWID,       "windowid",         VAR_NUMBER, VV_RO_SBX),
   VV(VV_PROGPATH,       "progpath",         VAR_STRING, VV_RO),
-  VV(VV_COMMAND_OUTPUT, "command_output",   VAR_STRING, 0),
   VV(VV_COMPLETED_ITEM, "completed_item",   VAR_DICT, VV_RO),
   VV(VV_OPTION_NEW,     "option_new",       VAR_STRING, VV_RO),
   VV(VV_OPTION_OLD,     "option_old",       VAR_STRING, VV_RO),
@@ -8117,8 +8116,7 @@ static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 
   ga_append(capture_ga, NUL);
   rettv->v_type = VAR_STRING;
-  rettv->vval.v_string = vim_strsave(capture_ga->ga_data);
-  ga_clear(capture_ga);
+  rettv->vval.v_string = capture_ga->ga_data;
 
   capture_ga = save_capture_ga;
 }
diff --git a/src/nvim/eval.h b/src/nvim/eval.h
index 0c0a6881f6..b798eae187 100644
--- a/src/nvim/eval.h
+++ b/src/nvim/eval.h
@@ -86,7 +86,6 @@ typedef enum {
     VV_OLDFILES,
     VV_WINDOWID,
     VV_PROGPATH,
-    VV_COMMAND_OUTPUT,
     VV_COMPLETED_ITEM,
     VV_OPTION_NEW,
     VV_OPTION_OLD,
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index ff28e3d133..39db831fe3 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -37,7 +37,7 @@ describe('api', function()
       os.remove(fname)
     end)
 
-    it("VimL error: fails (VimL error), does NOT update v:errmsg", function()
+    it("parse error: fails (specific error), does NOT update v:errmsg", function()
       -- Most API methods return generic errors (or no error) if a VimL
       -- expression fails; nvim_command returns the VimL error details.
       local status, rv = pcall(nvim, "command", "bogus_command")
@@ -45,6 +45,82 @@ describe('api', function()
       eq("E492:", string.match(rv, "E%d*:"))  -- VimL error was returned.
       eq("", nvim("eval", "v:errmsg"))        -- v:errmsg was not updated.
     end)
+
+    it("runtime error: fails (specific error)", function()
+      local status, rv = pcall(nvim, "command_output", "buffer 23487")
+      eq(false, status)                 -- nvim_command() failed.
+      eq("E86: Buffer 23487 does not exist", string.match(rv, "E%d*:.*"))
+      eq("", nvim("eval", "v:errmsg"))  -- v:errmsg was not updated.
+    end)
+  end)
+
+  describe('nvim_command_output', function()
+    it('does not induce hit-enter prompt', function()
+      -- Induce a hit-enter prompt use nvim_input (non-blocking).
+      nvim('command', 'set cmdheight=1')
+      nvim('input', [[:echo "hi\nhi2"<CR>]])
+
+      -- Verify hit-enter prompt.
+      eq({mode='r', blocking=true}, nvim("get_mode"))
+      nvim('input', [[<C-c>]])
+
+      -- Verify NO hit-enter prompt.
+      nvim('command_output', [[echo "hi\nhi2"]])
+      eq({mode='n', blocking=false}, nvim("get_mode"))
+    end)
+
+    it('captures command output', function()
+      eq('this is\nspinal tap',
+         nvim('command_output', [[echo "this is\nspinal tap"]]))
+    end)
+
+    it('captures empty command output', function()
+      eq('', nvim('command_output', 'echo'))
+    end)
+
+    it('captures single-char command output', function()
+      eq('x', nvim('command_output', 'echo "x"'))
+    end)
+
+    it('captures multiple commands', function()
+      eq('foo\n  1 %a   "[No Name]"                    line 1',
+        nvim('command_output', 'echo "foo" | ls'))
+    end)
+
+    it('captures nested execute()', function()
+      eq('\nnested1\nnested2\n  1 %a   "[No Name]"                    line 1',
+        nvim('command_output',
+          [[echo execute('echo "nested1\nnested2"') | ls]]))
+    end)
+
+    it('captures nested nvim_command_output()', function()
+      eq('nested1\nnested2\n  1 %a   "[No Name]"                    line 1',
+        nvim('command_output',
+          [[echo nvim_command_output('echo "nested1\nnested2"') | ls]]))
+    end)
+
+    it('does not return shell |:!| output', function()
+      eq(':!echo "foo"\r\n', nvim('command_output', [[!echo "foo"]]))
+    end)
+
+    it("parse error: fails (specific error), does NOT update v:errmsg", function()
+      local status, rv = pcall(nvim, "command_output", "bogus commannnd")
+      eq(false, status)                 -- nvim_command_output() failed.
+      eq("E492: Not an editor command: bogus commannnd",
+         string.match(rv, "E%d*:.*"))
+      eq("", nvim("eval", "v:errmsg"))  -- v:errmsg was not updated.
+      -- Verify NO hit-enter prompt.
+      eq({mode='n', blocking=false}, nvim("get_mode"))
+    end)
+
+    it("runtime error: fails (specific error)", function()
+      local status, rv = pcall(nvim, "command_output", "buffer 42")
+      eq(false, status)                 -- nvim_command_output() failed.
+      eq("E86: Buffer 42 does not exist", string.match(rv, "E%d*:.*"))
+      eq("", nvim("eval", "v:errmsg"))  -- v:errmsg was not updated.
+      -- Verify NO hit-enter prompt.
+      eq({mode='n', blocking=false}, nvim("get_mode"))
+    end)
   end)
 
   describe('nvim_eval', function()
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)
diff --git a/test/functional/ex_cmds/sign_spec.lua b/test/functional/ex_cmds/sign_spec.lua
index b37e6e8563..df0f5db860 100644
--- a/test/functional/ex_cmds/sign_spec.lua
+++ b/test/functional/ex_cmds/sign_spec.lua
@@ -16,8 +16,8 @@ describe('sign', function()
         nvim('command', 'sign place 34 line=3 name=Foo buffer='..buf2)
         -- now unplace without specifying a buffer
         nvim('command', 'sign unplace 34')
-        eq("\n--- Signs ---\n", nvim('command_output', 'sign place buffer='..buf1))
-        eq("\n--- Signs ---\n", nvim('command_output', 'sign place buffer='..buf2))
+        eq("--- Signs ---\n", nvim('command_output', 'sign place buffer='..buf1))
+        eq("--- Signs ---\n", nvim('command_output', 'sign place buffer='..buf2))
       end)
     end)
   end)
diff --git a/test/functional/helpers.lua b/test/functional/helpers.lua
index 31a2c3b3ff..dfc4694272 100644
--- a/test/functional/helpers.lua
+++ b/test/functional/helpers.lua
@@ -644,7 +644,7 @@ local function alter_slashes(obj)
 end
 
 local function hexdump(str)
-  local len = string.len( str )
+  local len = string.len(str)
   local dump = ""
   local hex = ""
   local asc = ""
@@ -652,22 +652,20 @@ local function hexdump(str)
   for i = 1, len do
     if 1 == i % 8 then
       dump = dump .. hex .. asc .. "\n"
-      hex = string.format( "%04x: ", i - 1 )
+      hex = string.format("%04x: ", i - 1)
       asc = ""
     end
 
-    local ord = string.byte( str, i )
-    hex = hex .. string.format( "%02x ", ord )
+    local ord = string.byte(str, i)
+    hex = hex .. string.format("%02x ", ord)
     if ord >= 32 and ord <= 126 then
-      asc = asc .. string.char( ord )
+      asc = asc .. string.char(ord)
     else
       asc = asc .. "."
     end
   end
 
-  return dump .. hex
-  .. string.rep( "   ", 8 - len % 8 ) .. asc
-
+  return dump .. hex .. string.rep("   ", 8 - len % 8) .. asc
 end
 
 local module = {
diff --git a/test/functional/ui/cmdline_highlight_spec.lua b/test/functional/ui/cmdline_highlight_spec.lua
index 73fe94c056..ffb6a26aef 100644
--- a/test/functional/ui/cmdline_highlight_spec.lua
+++ b/test/functional/ui/cmdline_highlight_spec.lua
@@ -849,7 +849,7 @@ describe('Ex commands coloring support', function()
       {EOB:~                                       }|
                                               |
     ]])
-    eq('\nError detected while processing :\nE605: Exception not caught: 42',
+    eq('Error detected while processing :\nE605: Exception not caught: 42',
        meths.command_output('messages'))
   end)
   it('errors out when failing to get callback', function()