feat(api): add ev.win to autocmd callback args #39826

Problem: Autocmd callbacks currently have to rely on curwin, which may
already have changed by the time they run. This is especially noticeable
for WinNew, WinClosed, WinResized and WinScrolled.

Solution: Track the window in the autocmd context and expose it as ev.win.
Pass it explicitly for the window events that need it.

2 files changed, 7 insertions, 6 deletions

diff --git a/src/nvim/api/autocmd.c b/src/nvim/api/autocmd.c
index f3b5aa780a..62fb5da9e4 100644
--- a/src/nvim/api/autocmd.c
+++ b/src/nvim/api/autocmd.c
@@ -373,13 +373,14 @@ cleanup:
 ///        - callback (`function|string?`) Lua function (or Vimscript function name, if string)
 ///          called when the event(s) is triggered. Lua callback can return |lua-truthy| to delete
 ///          the autocommand. Callback receives one argument, a table with keys: [event-args]()
-///            - buf: (`number`) [<abuf>]
+///            - buf: (`integer`) [<abuf>]
 ///            - data: (`any`) Arbitrary data passed from [nvim_exec_autocmds()] [event-data]()
 ///            - event: (`vim.api.keyset.events`) Name of the triggered event |autocmd-events|
 ///            - file: (`string`) [<afile>] (not expanded to a full path)
-///            - group: (`number?`) Group id, if any
-///            - id: (`number`) Autocommand id
+///            - group: (`integer?`) Group id, if any
+///            - id: (`integer`) Autocommand id
 ///            - match: (`string`) [<amatch>] (expanded to a full path)
+///            - win: (`integer`) id of the window for the event, see |window-ID|
 ///        - command (string?) Vim command executed on event. Not allowed with {callback}.
 ///        - desc (`string?`) Description (for documentation and troubleshooting).
 ///        - group (`string|integer?`) Group name or id to match against.
@@ -764,8 +765,8 @@ void nvim_exec_autocmds(Object event, Dict(exec_autocmds) *opts, Arena *arena, E
 
     FOREACH_ITEM(patterns, pat, {
       char *fname = !has_buf ? pat.data.string.data : NULL;
-      did_aucmd |= apply_autocmds_group(event_nr, fname, NULL, true, au_group, b, NULL, data,
-                                        has_buf);
+      did_aucmd |= apply_autocmds_group(event_nr, fname, NULL, true, au_group, b, curwin, NULL,
+                                        data, has_buf);
     })
   })
 
diff --git a/src/nvim/api/win_config.c b/src/nvim/api/win_config.c
index c7f3047a64..12ee0ccb61 100644
--- a/src/nvim/api/win_config.c
+++ b/src/nvim/api/win_config.c
@@ -299,7 +299,7 @@ Window nvim_open_win(Buffer buf, Boolean enter, Dict(win_config) *config, Error
     const bool result = ctx_switch(&switchwin, wp, tp, NULL, kCtxNoDisplay);
     assert(result);
     (void)result;
-    if (apply_autocmds(EVENT_WINNEW, NULL, NULL, false, curbuf)) {
+    if (apply_autocmds_win(EVENT_WINNEW, NULL, NULL, false, curbuf, wp)) {
       tp = win_find_tabpage(wp);
     }
     ctx_restore(&switchwin);