fix(terminal): forward streamed bracketed paste properly (#39152)

(cherry picked from commit 4eaf782bb6)

src/nvim/api/vim.c

@@ -1372,6 +1372,9 @@ Boolean nvim_paste(uint64_t channel_id, String data, Boolean crlf, Integer phase
   });
   if (phase == -1 || phase == 1) {  // Start of paste-stream.
     cancelled = false;
+    if (curbuf->terminal) {
+      terminal_set_streamed_paste(curbuf->terminal, true);
+    }
   } else if (cancelled) {
     // Skip remaining chunks.  Report error only once per "stream".
     goto theend;
@@ -1385,6 +1388,9 @@ Boolean nvim_paste(uint64_t channel_id, String data, Boolean crlf, Integer phase
   if (ERROR_SET(err) || (rv.type == kObjectTypeBoolean && !rv.data.boolean)) {
     cancelled = true;
   }
+  if ((phase == -1 || phase == 3 || cancelled) && curbuf->terminal) {
+    terminal_set_streamed_paste(curbuf->terminal, false);
+  }
   if (!cancelled && (phase == -1 || phase == 1)) {
     paste_store(channel_id, kFalse, NULL_STRING, crlf);
   }

src/nvim/terminal.c

@@ -197,6 +197,7 @@ struct terminal {
     MultiQueue *events;   ///< Events waiting for refresh.
   } pending;
 
+  bool streamed_paste;  ///< Streamed pasting
   bool theme_updates;  ///< Send a theme update notification when 'bg' changes
   bool synchronized_output;  ///< Mode 2026: suppress redraws until end of synchronized update
   bool sync_flush_pending;   ///< Set when mode 2026 ends; triggers immediate buffer refresh
@@ -1282,12 +1283,27 @@ static bool is_filter_char(int c)
   return !!(tpf_flags & flag);
 }
 
+void terminal_set_streamed_paste(Terminal *term, bool streamed)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (term->streamed_paste != streamed) {
+    if (streamed) {
+      vterm_keyboard_start_paste(curbuf->terminal->vt);
+    } else {
+      vterm_keyboard_end_paste(curbuf->terminal->vt);
+    }
+  }
+  term->streamed_paste = streamed;
+}
+
 void terminal_paste(int count, String *y_array, size_t y_size)
 {
   if (y_size == 0) {
     return;
   }
-  vterm_keyboard_start_paste(curbuf->terminal->vt);
+  if (!curbuf->terminal->streamed_paste) {
+    vterm_keyboard_start_paste(curbuf->terminal->vt);
+  }
   size_t buff_len = y_array[0].size;
   char *buff = xmalloc(buff_len);
   for (int i = 0; i < count; i++) {
@@ -1321,7 +1337,9 @@ void terminal_paste(int count, String *y_array, size_t y_size)
     }
   }
   xfree(buff);
-  vterm_keyboard_end_paste(curbuf->terminal->vt);
+  if (!curbuf->terminal->streamed_paste) {
+    vterm_keyboard_end_paste(curbuf->terminal->vt);
+  }
 }
 
 static void terminal_send_key(Terminal *term, int c)

test/functional/api/vim_spec.lua

@@ -1228,6 +1228,67 @@ describe('API', function()
       end)
       run_streamed_paste_tests()
     end)
+    describe('stream: terminal buffer', function()
+      local eol = is_os('win') and '\r\n' or '\n'
+      before_each(function()
+        exec_lua(function()
+          _G.input = {}
+          _G.chan = vim.api.nvim_open_term(0, {
+            on_input = function(_, _, _, data)
+              if #data > 0 then
+                table.insert(_G.input, data)
+              end
+            end,
+            force_crlf = false,
+          })
+        end)
+      end)
+      local function run_terminal_streamed_paste_tests(check_dot_repeat)
+        it('without bracketed paste mode in terminal', function()
+          api.nvim_paste('AA\nBB\n', false, 1)
+          eq({ 'AA', eol, 'BB', eol }, exec_lua('return _G.input'))
+          api.nvim_paste('CC', false, 2)
+          eq({ 'AA', eol, 'BB', eol, 'CC' }, exec_lua('return _G.input'))
+          api.nvim_paste('\nDD', false, 3)
+          eq({ 'AA', eol, 'BB', eol, 'CC', eol, 'DD' }, exec_lua('return _G.input'))
+          if check_dot_repeat then
+            exec_lua('_G.input = {}')
+            feed('.')
+            eq({ 'AA', eol, 'BB', eol, 'CC', eol, 'DD' }, exec_lua('return _G.input'))
+          end
+        end)
+        it('with bracketed paste mode in terminal', function()
+          exec_lua([[vim.api.nvim_chan_send(_G.chan, '\027[?2004h')]])
+          api.nvim_paste('AA\nBB\n', false, 1)
+          eq({ '\027[200~', 'AA', eol, 'BB', eol }, exec_lua('return _G.input'))
+          api.nvim_paste('CC', false, 2)
+          eq({ '\027[200~', 'AA', eol, 'BB', eol, 'CC' }, exec_lua('return _G.input'))
+          api.nvim_paste('\nDD', false, 3)
+          eq(
+            { '\027[200~', 'AA', eol, 'BB', eol, 'CC', eol, 'DD', '\027[201~' },
+            exec_lua('return _G.input')
+          )
+          if check_dot_repeat then
+            exec_lua('_G.input = {}')
+            feed('.')
+            eq(
+              { '\027[200~', 'AA', eol, 'BB', eol, 'CC', eol, 'DD', '\027[201~' },
+              exec_lua('return _G.input')
+            )
+          end
+        end)
+      end
+      describe('in Normal mode', function()
+        run_terminal_streamed_paste_tests(true)
+      end)
+      describe('in Terminal mode', function()
+        before_each(function()
+          feed('i')
+          eq({ mode = 't', blocking = false }, api.nvim_get_mode())
+        end)
+        run_terminal_streamed_paste_tests(false)
+      end)
+    end)
     it('non-streaming', function()
       -- With final "\n".
       api.nvim_paste('line 1\nline 2\nline 3\n', true, -1)
@@ -1947,7 +2008,6 @@ describe('API', function()
     it('getting current buffer option does not adjust cursor #19381', function()
       command('new')
       local buf = api.nvim_get_current_buf()
-      print(vim.inspect(api.nvim_get_current_buf()))
       local win = api.nvim_get_current_win()
       insert('some text')
       feed('0v$')