fix(autocmd): API functions accept garbage after event name #25523

"VimEnter foo" was accepted as a valid event name for "VimEnter".
Events delimited with commas, eg. "VimEnter,BufRead", were also
accepted, even though only the first event was actually parsed.

Co-authored-by: ii14 <ii14@users.noreply.github.com>

2 files changed, 18 insertions, 8 deletions

diff --git a/src/nvim/api/autocmd.c b/src/nvim/api/autocmd.c
index 768ed869cc..d19f44798b 100644
--- a/src/nvim/api/autocmd.c
+++ b/src/nvim/api/autocmd.c
@@ -33,13 +33,11 @@
 // Copy string or array of strings into an empty array.
 // Get the event number, unless it is an error. Then goto `goto_name`.
 #define GET_ONE_EVENT(event_nr, event_str, goto_name) \
-  char *__next_ev; \
   event_T event_nr = \
-    event_name2nr(event_str.data.string.data, &__next_ev); \
-  if (event_nr >= NUM_EVENTS) { \
-    api_set_error(err, kErrorTypeValidation, "unexpected event"); \
+    event_name2nr_str(event_str.data.string); \
+  VALIDATE_S((event_nr < NUM_EVENTS), "event", event_str.data.string.data, { \
     goto goto_name; \
-  }
+  });
 
 // ID for associating autocmds created via nvim_create_autocmd
 // Used to delete autocmds from nvim_del_autocmd
diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 9f7c599164..2537269c5c 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -597,9 +597,9 @@ bool is_aucmd_win(win_T *win)
   return false;
 }
 
-// Return the event number for event name "start".
-// Return NUM_EVENTS if the event name was not found.
-// Return a pointer to the next event name in "end".
+/// Return the event number for event name "start".
+/// Return NUM_EVENTS if the event name was not found.
+/// Return a pointer to the next event name in "end".
 event_T event_name2nr(const char *start, char **end)
 {
   const char *p;
@@ -623,6 +623,18 @@ event_T event_name2nr(const char *start, char **end)
   return event_names[i].event;
 }
 
+/// Return the event number for event name "str".
+/// Return NUM_EVENTS if the event name was not found.
+event_T event_name2nr_str(String str)
+{
+  for (int i = 0; event_names[i].name != NULL; i++) {
+    if (str.size == event_names[i].len && STRNICMP(str.data, event_names[i].name, str.size) == 0) {
+      return event_names[i].event;
+    }
+  }
+  return NUM_EVENTS;
+}
+
 /// Return the name for event
 ///
 /// @param[in]  event  Event to return name for.