refactor(terminal): impl "[Process exited]" in Lua #38343

Problem:
"[Process exited]" is implemented in C with anonymous namespace
and users have no way to hide it.

Solution:
- Handle "TermClose" event in Lua.
- User can delete the "nvim.terminal" augroup to avoid "[Process exited]".

runtime/doc/vim_diff.txt

@@ -180,6 +180,7 @@ nvim.terminal:
 - BufReadCmd: Treats "term://" buffers as |terminal| buffers. |terminal-start|
 - TermClose: A |terminal| buffer started with no arguments (which thus uses
   'shell') and which exits with no error is closed automatically.
+- TermClose: Displays the "[Process exited]" virtual text.
 - TermRequest: The terminal emulator responds to OSC background and foreground
   requests, indicating (1) a black background and white foreground when Nvim
   option 'background' is "dark" or (2) a white background and black foreground

runtime/lua/vim/_core/defaults.lua

@@ -578,6 +578,54 @@ do
     end,
   })
 
+  local nvim_terminal_exitmsg_ns = vim.api.nvim_create_namespace('nvim.terminal.exitmsg')
+
+  --- @param buf integer
+  --- @param msg string
+  --- @param pos integer
+  local function set_terminal_exitmsg(buf, msg, pos)
+    vim.api.nvim_buf_set_extmark(buf, nvim_terminal_exitmsg_ns, pos, 0, {
+      virt_text = { { msg, nil } },
+      virt_text_pos = 'overlay',
+    })
+  end
+
+  vim.api.nvim_create_autocmd('TermClose', {
+    group = nvim_terminal_augroup,
+    nested = true,
+    desc = 'Displays the "[Process exited]" virtual text',
+    callback = function(ev)
+      if not vim.api.nvim_buf_is_valid(ev.buf) then
+        return
+      end
+
+      local buf = vim.bo[ev.buf]
+      local pos = ev.data.pos ---@type integer
+      local buf_has_exitmsg = #(
+          vim.api.nvim_buf_get_extmarks(ev.buf, nvim_terminal_exitmsg_ns, 0, -1, {})
+        ) > 0
+
+      -- `nvim_open_term` buffers do not have any attached chan
+      local msg = buf.channel == 0 and '[Terminal closed]'
+        or ('[Process exited %d]'):format(vim.v.event.status)
+
+      -- TermClose may be queued before TermOpen if the process
+      -- exits before `terminal_open` is called. Don't display
+      -- the msg now, let TermOpen display it.
+      if buf.buftype ~= 'terminal' or buf_has_exitmsg then
+        vim.api.nvim_create_autocmd('TermOpen', {
+          buffer = ev.buf,
+          once = true,
+          callback = function()
+            set_terminal_exitmsg(ev.buf, msg, pos)
+          end,
+        })
+        return
+      end
+      set_terminal_exitmsg(ev.buf, msg, pos)
+    end,
+  })
+
   vim.api.nvim_create_autocmd('TermRequest', {
     group = nvim_terminal_augroup,
     desc = 'Handles OSC foreground/background color requests',
@@ -694,6 +742,9 @@ do
       vim.keymap.set({ 'n', 'x', 'o' }, ']]', function()
         jump_to_prompt(nvim_terminal_prompt_ns, 0, ev.buf, vim.v.count1)
       end, { buffer = ev.buf, desc = 'Jump [count] shell prompts forward' })
+
+      -- If the terminal buffer is being reused, clear the previous exit msg
+      vim.api.nvim_buf_clear_namespace(ev.buf, nvim_terminal_exitmsg_ns, 0, -1)
     end,
   })
 

src/nvim/terminal.c

@@ -64,7 +64,6 @@
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/time.h"
 #include "nvim/ex_docmd.h"
-#include "nvim/extmark.h"
 #include "nvim/getchar.h"
 #include "nvim/globals.h"
 #include "nvim/grid.h"
@@ -211,7 +210,6 @@ struct terminal {
   VTermTerminator termrequest_terminator;  ///< Terminator (BEL or ST) used in the termrequest
 
   size_t refcount;                  // reference count
-  uint32_t exitmsg_id;
 };
 
 static VTermScreenCallbacks vterm_screen_callbacks = {
@@ -681,10 +679,6 @@ void terminal_close(Terminal **termpp, int status)
     // If called from buf_close_terminal() after the process has already exited, we
     // only need to call the close callback to clean up the terminal object.
     only_destroy = true;
-    // Buffer may be reused so delete the "[Process exited]" msg
-    if (buf) {
-      extmark_del_id(buf, (uint32_t)-1, term->exitmsg_id);
-    }
   } else {
     // flush any pending changes to the buffer
     if (!exiting) {
@@ -695,6 +689,7 @@ void terminal_close(Terminal **termpp, int status)
     term->closed = true;
   }
 
+  int pos = buf ? buf->b_ml.ml_line_count - 1 : 0;
   if (status == -1 || exiting) {
     // If this was called by buf_close_terminal() (status is -1), or if exiting, we
     // must inform the buffer the terminal no longer exists so that buf_freeall()
@@ -714,37 +709,15 @@ void terminal_close(Terminal **termpp, int status)
   } else if (!only_destroy) {
     // Associated channel has been closed and the editor is not exiting.
     // Do not call the close callback now. Wait for the user to press a key.
-    char msg[sizeof("[Process exited ]") + NUMBUFLEN];
-    if (((Channel *)term->opts.data)->streamtype == kChannelStreamInternal) {
-      snprintf(msg, sizeof msg, "[Terminal closed]");
-    } else {
-      snprintf(msg, sizeof msg, "[Process exited %d]", status);
-    }
-
-    // Show the msg as virtual text instead of adding it to buffer
-    VirtTextChunk *chunk = xmalloc(sizeof(VirtTextChunk));
-    *chunk = (VirtTextChunk) { .text = xstrdup(msg), .hl_id = -1 };
-    DecorVirtText *virt_text = xmalloc(sizeof(DecorVirtText));
-    *virt_text = (DecorVirtText) {
-      .priority = DECOR_PRIORITY_BASE,
-      .pos = kVPosWinCol,
-      .data.virt_text = { .items = chunk, .size = 1 }
-    };
-    DecorInline decor = {
-      .ext = true, .data.ext = { .sh_idx = DECOR_ID_INVALID, .vt = virt_text }
-    };
-
-    int pos = MIN(row_to_linenr(term, term->cursor.row),
-                  buf->b_ml.ml_line_count - 1);
-    extmark_set(buf, (uint32_t)-1, &term->exitmsg_id, pos, 0, -1, 0,
-                decor, 0, true, false, true, false, NULL);
-
     // Redraw statusline to show the exit code.
     FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
       if (wp->w_buffer == buf) {
         wp->w_redr_status = true;
       }
     }
+
+    // Gets the line number to display "[Process exited]" virt text
+    pos = MIN(row_to_linenr(term, term->cursor.row), pos);
   }
 
   if (only_destroy) {
@@ -756,7 +729,13 @@ void terminal_close(Terminal **termpp, int status)
     dict_T *dict = get_v_event(&save_v_event);
     tv_dict_add_nr(dict, S_LEN("status"), status);
     tv_dict_set_keys_readonly(dict);
-    apply_autocmds(EVENT_TERMCLOSE, NULL, NULL, false, buf);
+
+    MAXSIZE_TEMP_DICT(data, 1);
+    PUT_C(data, "pos", INTEGER_OBJ(pos));
+
+    apply_autocmds_group(EVENT_TERMCLOSE, NULL, NULL, status >= 0, AUGROUP_ALL,
+                         buf, NULL, &DICT_OBJ(data));
+
     restore_v_event(dict, &save_v_event);
   }
 }

test/functional/terminal/ex_terminal_spec.lua

@@ -215,7 +215,7 @@ local function test_terminal_with_fake_shell(backslash)
     command('terminal')
     screen:expect([[
       ^ready $                                           |
-      [Process exited 0]                                |
+                                                        |
                                                         |*2
     ]])
   end)
@@ -297,7 +297,7 @@ local function test_terminal_with_fake_shell(backslash)
     command('terminal')
     screen:expect([[
       ^ready $                                           |
-      [Process exited 0]                                |
+                                                        |
                                                         |*2
     ]])
     eq('term://', string.match(eval('bufname("%")'), '^term://'))