Merge pull request #10112 from bfredl/noautobuf

api/buffer: avoid spurios Buf[Win]Enter in nvim_buf_set_lines

2 files changed, 33 insertions, 7 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 9b5e0fc40b..2e8ca384b4 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -27,6 +27,7 @@
 #include "nvim/types.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/screen.h"
+#include "nvim/memline.h"
 #include "nvim/memory.h"
 #include "nvim/message.h"
 #include "nvim/edit.h"
@@ -977,11 +978,20 @@ Buffer nvim_create_buf(Boolean listed, Boolean scratch, Error *err)
                            BLN_NOOPT | BLN_NEW | (listed ? BLN_LISTED : 0));
   try_end(err);
   if (buf == NULL) {
-    if (!ERROR_SET(err)) {
-      api_set_error(err, kErrorTypeException, "Failed to create buffer");
-    }
-    return 0;
+    goto fail;
   }
+
+  // Open the memline for the buffer. This will avoid spurious autocmds when
+  // a later nvim_buf_set_lines call would have needed to "open" the buffer.
+  try_start();
+  block_autocmds();
+  int status = ml_open(buf);
+  unblock_autocmds();
+  try_end(err);
+  if (status == FAIL) {
+    goto fail;
+  }
+
   if (scratch) {
     aco_save_T aco;
     aucmd_prepbuf(&aco, buf);
@@ -991,6 +1001,12 @@ Buffer nvim_create_buf(Boolean listed, Boolean scratch, Error *err)
     aucmd_restbuf(&aco);
   }
   return buf->b_fnum;
+
+fail:
+  if (!ERROR_SET(err)) {
+    api_set_error(err, kErrorTypeException, "Failed to create buffer");
+  }
+  return 0;
 }
 
 /// Open a new window.
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 69bd584ab4..4279a5d420 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -1336,7 +1336,7 @@ describe('API', function()
       eq({id=2}, meths.create_buf(true, false))
       eq({id=3}, meths.create_buf(false, false))
       eq('  1 %a   "[No Name]"                    line 1\n'..
-         '  2      "[No Name]"                    line 0',
+         '  2  h   "[No Name]"                    line 0',
          meths.command_output("ls"))
       -- current buffer didn't change
       eq({id=1}, meths.get_current_buf())
@@ -1367,14 +1367,24 @@ describe('API', function()
       eq({id=1}, meths.get_current_buf())
     end)
 
+    it("doesn't cause BufEnter or BufWinEnter autocmds", function()
+      command("let g:fired = v:false")
+      command("au BufEnter,BufWinEnter * let g:fired = v:true")
+
+      eq({id=2}, meths.create_buf(true, false))
+      meths.buf_set_lines(2, 0, -1, true, {"test", "text"})
+
+      eq(false, eval('g:fired'))
+    end)
+
     it('|scratch-buffer|', function()
       eq({id=2}, meths.create_buf(false, true))
       eq({id=3}, meths.create_buf(true, true))
       eq({id=4}, meths.create_buf(true, true))
       local scratch_bufs = { 2, 3, 4 }
       eq('  1 %a   "[No Name]"                    line 1\n'..
-         '  3      "[Scratch]"                    line 0\n'..
-         '  4      "[Scratch]"                    line 0',
+         '  3  h   "[Scratch]"                    line 0\n'..
+         '  4  h   "[Scratch]"                    line 0',
          meths.command_output("ls"))
       -- current buffer didn't change
       eq({id=1}, meths.get_current_buf())