fix(context): don't crash on invalid arg to nvim_get_context (#25977)

Note: The crash happens in the second test case when using uninitialized
memory, and therefore doesn't happen with ASAN.

2 files changed, 6 insertions, 4 deletions

diff --git a/src/nvim/api/private/converter.c b/src/nvim/api/private/converter.c
index 10152cb3c8..d9832abd76 100644
--- a/src/nvim/api/private/converter.c
+++ b/src/nvim/api/private/converter.c
@@ -261,7 +261,9 @@ Object vim_to_object(typval_T *obj)
 /// @param obj  Object to convert from.
 /// @param tv   Conversion result is placed here. On failure member v_type is
 ///             set to VAR_UNKNOWN (no allocation was made for this variable).
-/// returns     true if conversion is successful, otherwise false.
+/// @param err  Error object.
+///
+/// @returns    true if conversion is successful, otherwise false.
 bool object_to_vim(Object obj, typval_T *tv, Error *err)
 {
   tv->v_type = VAR_UNKNOWN;
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index c3c619e206..8446f5b383 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1402,7 +1402,7 @@ Dictionary nvim_get_context(Dict(context) *opts, Error *err)
 /// Sets the current editor state from the given |context| map.
 ///
 /// @param  dict  |Context| map.
-Object nvim_load_context(Dictionary dict)
+Object nvim_load_context(Dictionary dict, Error *err)
   FUNC_API_SINCE(6)
 {
   Context ctx = CONTEXT_INIT;
@@ -1410,8 +1410,8 @@ Object nvim_load_context(Dictionary dict)
   int save_did_emsg = did_emsg;
   did_emsg = false;
 
-  ctx_from_dict(dict, &ctx);
-  if (!did_emsg) {
+  ctx_from_dict(dict, &ctx, err);
+  if (!ERROR_SET(err)) {
     ctx_restore(&ctx, kCtxAll);
   }