feat(buffer_updates): allow ignoring when previewing

Also adds a test that we actually subscribe to buffer events when in
CMDPREVIEW.

runtime/lua/vim/treesitter.lua

@@ -50,7 +50,7 @@ function M._create_parser(bufnr, lang, opts)
     end
   end
 
-  a.nvim_buf_attach(self.bufnr, false, {on_bytes=bytes_cb, on_detach=detach_cb})
+  a.nvim_buf_attach(self.bufnr, false, {on_bytes=bytes_cb, on_detach=detach_cb, preview=true})
 
   self:parse()
 

src/nvim/api/buffer.c

@@ -121,6 +121,8 @@ Integer nvim_buf_line_count(Buffer buffer, Error *err)
 ///               - buffer handle
 ///             - utf_sizes: include UTF-32 and UTF-16 size of the replaced
 ///               region, as args to `on_lines`.
+///             - preview: also attach to command preview (i.e. 'inccommand')
+///               events.
 /// @param[out] err Error details, if any
 /// @return False if attach failed (invalid parameter, or buffer isn't loaded);
 ///         otherwise True. TODO: LUA_API_NO_EVAL
@@ -176,6 +178,12 @@ Boolean nvim_buf_attach(uint64_t channel_id,
         goto error;
       }
       cb.utf_sizes = v->data.boolean;
+    } else if (is_lua && strequal("preview", k.data)) {
+      if (v->type != kObjectTypeBoolean) {
+        api_set_error(err, kErrorTypeValidation, "preview must be boolean");
+        goto error;
+      }
+      cb.preview = v->data.boolean;
     } else {
       api_set_error(err, kErrorTypeValidation, "unexpected key: %s", k.data);
       goto error;

src/nvim/buffer_defs.h

@@ -491,9 +491,10 @@ typedef struct {
   LuaRef on_changedtick;
   LuaRef on_detach;
   bool utf_sizes;
+  bool preview;
 } BufUpdateCallbacks;
 #define BUF_UPDATE_CALLBACKS_INIT { LUA_NOREF, LUA_NOREF, LUA_NOREF, \
-                                    LUA_NOREF, false }
+                                    LUA_NOREF, false, false }
 
 EXTERN int curbuf_splice_pending INIT(= 0);
 

src/nvim/buffer_updates.c

@@ -237,7 +237,7 @@ void buf_updates_send_changes(buf_T *buf,
   for (size_t i = 0; i < kv_size(buf->update_callbacks); i++) {
     BufUpdateCallbacks cb = kv_A(buf->update_callbacks, i);
     bool keep = true;
-    if (cb.on_lines != LUA_NOREF) {
+    if (cb.on_lines != LUA_NOREF && (cb.preview || !(State & CMDPREVIEW))) {
       Array args = ARRAY_DICT_INIT;
       Object items[8];
       args.size = 6;  // may be increased to 8 below
@@ -298,7 +298,7 @@ void buf_updates_send_splice(
   for (size_t i = 0; i < kv_size(buf->update_callbacks); i++) {
     BufUpdateCallbacks cb = kv_A(buf->update_callbacks, i);
     bool keep = true;
-    if (cb.on_bytes != LUA_NOREF) {
+    if (cb.on_bytes != LUA_NOREF && (cb.preview || !(State & CMDPREVIEW))) {
       FIXED_TEMP_ARRAY(args, 11);
 
       // the first argument is always the buffer handle

test/functional/lua/buffer_updates_spec.lua

@@ -25,14 +25,14 @@ local function attach_buffer(evname)
     local evname = ...
     local events = {}
 
-    function test_register(bufnr, id, changedtick, utf_sizes)
+    function test_register(bufnr, id, changedtick, utf_sizes, preview)
       local function callback(...)
         table.insert(events, {id, ...})
         if test_unreg == id then
           return true
         end
       end
-      local opts = {[evname]=callback, on_detach=callback, utf_sizes=utf_sizes}
+      local opts = {[evname]=callback, on_detach=callback, utf_sizes=utf_sizes, preview=preview}
       if changedtick then
         opts.on_changedtick = callback
       end
@@ -290,7 +290,7 @@ describe('lua: nvim_buf_attach on_bytes', function()
     if verify then
       meths.buf_get_offset(0, meths.buf_line_count(0))
     end
-    exec_lua("return test_register(...)", 0, "test1",false, nil)
+    exec_lua("return test_register(...)", 0, "test1", false, false, true)
     meths.buf_get_changedtick(0)
 
     local verify_name = "test1"
@@ -493,6 +493,23 @@ describe('lua: nvim_buf_attach on_bytes', function()
       }
 
     end)
+
+    it('inccomand=nosplit and substitute', function()
+      if verify then pending("Verification can't be done when previewing") end
+
+      local check_events = setup_eventcheck(verify, {"abcde"})
+      meths.set_option('inccommand', 'nosplit')
+
+      feed ':%s/bcd/'
+      check_events {
+        { "test1", "bytes", 1, 3, 0, 1, 1, 0, 3, 3, 0, 0, 0 };
+      }
+
+      feed 'a'
+      check_events {
+        { "test1", "bytes", 1, 3, 0, 1, 1, 0, 3, 3, 0, 1, 1 };
+      }
+    end)
   end
 
   describe('(with verify) handles', function()