commit 3cb462a9608f67fca3873e4ade1cd552d0220c44
parent 6082b7f850b592a9d2e3a55b00b22dc862ad1858
Author: Sean Dewar <6256228+seandewar@users.noreply.github.com>
Date: Fri, 9 May 2025 00:26:07 +0100
fix(api): autocmds mess up nvim_get_option_value's dummy buffer
Problem: When the "filetype" key is set for nvim_get_option_value, autocommands
can crash Nvim by prematurely wiping the dummy buffer, or cause options intended
for it to instead be set for unrelated buffers if switched during OptionSet.
Solution: Don't crash. Also quash side-effects from setting the buffer options.
Diffstat:
2 files changed, 73 insertions(+), 13 deletions(-)
diff --git a/src/nvim/api/options.c b/src/nvim/api/options.c
@@ -13,6 +13,7 @@
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/globals.h"
+#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/memory_defs.h"
#include "nvim/option.h"
@@ -99,8 +100,10 @@ static int validate_option_value_args(Dict(option) *opts, char *name, OptIndex *
}
/// Create a dummy buffer and run the FileType autocmd on it.
-static buf_T *do_ft_buf(char *filetype, aco_save_T *aco, Error *err)
+static buf_T *do_ft_buf(const char *filetype, aco_save_T *aco, bool *aco_used, Error *err)
+ FUNC_ATTR_NONNULL_ARG(2, 3, 4)
{
+ *aco_used = false;
if (filetype == NULL) {
return NULL;
}
@@ -112,19 +115,37 @@ static buf_T *do_ft_buf(char *filetype, aco_save_T *aco, Error *err)
return NULL;
}
+ // Open a memline for use by autocommands.
+ if (ml_open(ftbuf) == FAIL) {
+ api_set_error(err, kErrorTypeException, "Could not load internal buffer");
+ return ftbuf;
+ }
+
+ bufref_T bufref;
+ set_bufref(&bufref, ftbuf);
+
// Set curwin/curbuf to buf and save a few things.
aucmd_prepbuf(aco, ftbuf);
+ *aco_used = true;
- TRY_WRAP(err, {
- set_option_value(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"), OPT_LOCAL);
- set_option_value(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"), OPT_LOCAL);
- set_option_value(kOptSwapfile, BOOLEAN_OPTVAL(false), OPT_LOCAL);
- set_option_value(kOptModeline, BOOLEAN_OPTVAL(false), OPT_LOCAL); // 'nomodeline'
+ set_option_direct(kOptBufhidden, STATIC_CSTR_AS_OPTVAL("hide"), OPT_LOCAL, SID_NONE);
+ set_option_direct(kOptBuftype, STATIC_CSTR_AS_OPTVAL("nofile"), OPT_LOCAL, SID_NONE);
+ assert(ftbuf->b_ml.ml_mfp->mf_fd < 0); // ml_open() should not have opened swapfile already
+ ftbuf->b_p_swf = false;
+ ftbuf->b_p_ml = false;
+ ftbuf->b_p_ft = xstrdup(filetype);
- ftbuf->b_p_ft = xstrdup(filetype);
+ TRY_WRAP(err, {
do_filetype_autocmd(ftbuf, false);
});
+ if (!bufref_valid(&bufref)) {
+ if (!ERROR_SET(err)) {
+ api_set_error(err, kErrorTypeException, "Internal buffer was deleted");
+ }
+ return NULL;
+ }
+
return ftbuf;
}
@@ -161,13 +182,15 @@ Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
}
aco_save_T aco;
+ bool aco_used;
- buf_T *ftbuf = do_ft_buf(filetype, &aco, err);
+ buf_T *ftbuf = do_ft_buf(filetype, &aco, &aco_used, err);
if (ERROR_SET(err)) {
- if (ftbuf != NULL) {
+ if (aco_used) {
// restore curwin/curbuf and a few other things
aucmd_restbuf(&aco);
-
+ }
+ if (ftbuf != NULL) {
assert(curbuf != ftbuf); // safety check
wipe_buffer(ftbuf, false);
}
@@ -183,9 +206,10 @@ Object nvim_get_option_value(String name, Dict(option) *opts, Error *err)
OptVal value = get_option_value_for(opt_idx, opt_flags, scope, from, err);
if (ftbuf != NULL) {
- // restore curwin/curbuf and a few other things
- aucmd_restbuf(&aco);
-
+ if (aco_used) {
+ // restore curwin/curbuf and a few other things
+ aucmd_restbuf(&aco);
+ }
assert(curbuf != ftbuf); // safety check
wipe_buffer(ftbuf, false);
}
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
@@ -1977,6 +1977,42 @@ describe('API', function()
]])
eq(false, api.nvim_get_option_value('modified', {}))
end)
+
+ it('errors if autocmds wipe the dummy buffer', function()
+ -- Wipe the dummy buffer. This will throw E813, but the buffer will still be wiped; check that
+ -- such errors from setting the filetype have priority.
+ command 'autocmd FileType * ++once bwipeout!'
+ eq(
+ 'FileType Autocommands for "*": Vim(bwipeout):E813: Cannot close autocmd window',
+ pcall_err(api.nvim_get_option_value, 'formatexpr', { filetype = 'lua' })
+ )
+
+ -- Silence E813 to check that the error for wiping the dummy buffer is set.
+ command 'autocmd FileType * ++once silent! bwipeout!'
+ eq(
+ 'Internal buffer was deleted',
+ pcall_err(api.nvim_get_option_value, 'formatexpr', { filetype = 'lua' })
+ )
+ end)
+
+ it('sets dummy buffer options without side-effects', function()
+ exec [[
+ let g:events = []
+ autocmd OptionSet * let g:events += [expand("<amatch>")]
+ autocmd FileType * ++once let g:bufhidden = &l:bufhidden
+ \| let g:buftype = &l:buftype
+ \| let g:swapfile = &l:swapfile
+ \| let g:modeline = &l:modeline
+ \| let g:bufloaded = bufloaded(bufnr())
+ ]]
+ api.nvim_get_option_value('formatexpr', { filetype = 'lua' })
+ eq({}, eval('g:events'))
+ eq('hide', eval('g:bufhidden'))
+ eq('nofile', eval('g:buftype'))
+ eq(0, eval('g:swapfile'))
+ eq(0, eval('g:modeline'))
+ eq(1, eval('g:bufloaded'))
+ end)
end)
describe('nvim_{get,set}_current_buf, nvim_list_bufs', function()
