5 files changed, 17 insertions, 14 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index 81d25d7c95..cffc7a2e38 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -65,7 +65,7 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
   index = convert_index(index);
   Array slice = nvim_buf_get_lines(0, buffer, index, index+1, true, err);
 
-  if (!err->set && slice.size) {
+  if (!ERROR_SET(err) && slice.size) {
     rv = slice.items[0].data.string;
   }
 
@@ -203,7 +203,7 @@ ArrayOf(String) nvim_buf_get_lines(uint64_t channel_id,
   }
 
 end:
-  if (err->set) {
+  if (ERROR_SET(err)) {
     for (size_t i = 0; i < rv.size; i++) {
       xfree(rv.items[i].data.string.data);
     }
diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index a07422bd12..60bf38265f 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -8,9 +8,11 @@
 #define ARRAY_DICT_INIT {.size = 0, .capacity = 0, .items = NULL}
 #define STRING_INIT {.data = NULL, .size = 0}
 #define OBJECT_INIT { .type = kObjectTypeNil }
-#define ERROR_INIT { .set = false, .msg = NULL }
+#define ERROR_INIT { .type = kErrorTypeNone, .msg = NULL }
 #define REMOTE_TYPE(type) typedef handle_T type
 
+#define ERROR_SET(e) ((e)->type != kErrorTypeNone)
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # define ArrayOf(...) Array
 # define DictionaryOf(...) Dictionary
@@ -20,6 +22,7 @@ typedef int handle_T;
 
 // Basic types
 typedef enum {
+  kErrorTypeNone = -1,
   kErrorTypeException,
   kErrorTypeValidation
 } ErrorType;
@@ -39,7 +42,6 @@ typedef enum {
 typedef struct {
   ErrorType type;
   char *msg;
-  bool set;
 } Error;
 
 typedef bool Boolean;
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 3bf584ff2f..58534d78a0 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -69,7 +69,7 @@ bool try_end(Error *err)
                                              ET_ERROR,
                                              NULL,
                                              &should_free);
-    _api_set_error(err, err->type, "%s", msg);
+    _api_set_error(err, kErrorTypeException, "%s", msg);
     free_global_msglist();
 
     if (should_free) {
@@ -80,7 +80,7 @@ bool try_end(Error *err)
     discard_current_exception();
   }
 
-  return err->set;
+  return ERROR_SET(err);
 }
 
 /// Recursively expands a vimscript value in a dict
@@ -803,11 +803,12 @@ void api_free_dictionary(Dictionary value)
 void api_clear_error(Error *value)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (!value->set) {
+  if (!ERROR_SET(value)) {
     return;
   }
   xfree(value->msg);
   value->msg = NULL;
+  value->type = kErrorTypeNone;
 }
 
 Dictionary api_metadata(void)
@@ -953,7 +954,7 @@ static void set_option_value_for(char *key,
       break;
   }
 
-  if (err->set) {
+  if (ERROR_SET(err)) {
     return;
   }
 
@@ -981,6 +982,7 @@ static void set_option_value_err(char *key,
 void _api_set_error(Error *err, ErrorType errType, const char *format, ...)
   FUNC_ATTR_NONNULL_ALL
 {
+  assert(kErrorTypeNone != errType);
   va_list args1;
   va_list args2;
   va_start(args1, format);
@@ -994,6 +996,5 @@ void _api_set_error(Error *err, ErrorType errType, const char *format, ...)
   vsnprintf(err->msg, bufsize, format, args2);
   va_end(args2);
 
-  err->set = true;
   err->type = errType;
 }
diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index 534274db0f..4c39bc57eb 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -97,7 +97,7 @@ void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
 
   for (size_t i = 0; i < options.size; i++) {
     ui_set_option(ui, options.items[i].key, options.items[i].value, err);
-    if (err->set) {
+    if (ERROR_SET(err)) {
       xfree(ui);
       return;
     }
@@ -165,7 +165,7 @@ void nvim_ui_set_option(uint64_t channel_id, String name,
   UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
 
   ui_set_option(ui, name, value, error);
-  if (!error->set) {
+  if (!ERROR_SET(error)) {
     ui_refresh();
   }
 }
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 2c78ffdec1..924ea419a1 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -165,7 +165,7 @@ String nvim_command_output(String str, Error *err)
   nvim_command(str, err);
   do_cmdline_cmd("redir END");
 
-  if (err->set) {
+  if (ERROR_SET(err)) {
     return (String) STRING_INIT;
   }
 
@@ -776,7 +776,7 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
     MsgpackRpcRequestHandler handler = msgpack_rpc_get_handler_for(name.data,
                                                                    name.size);
     Object result = handler.fn(channel_id, args, &nested_error);
-    if (nested_error.set) {
+    if (ERROR_SET(&nested_error)) {
       // error handled after loop
       break;
     }
@@ -785,7 +785,7 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
   }
 
   ADD(rv, ARRAY_OBJ(results));
-  if (nested_error.set) {
+  if (ERROR_SET(&nested_error)) {
     Array errval = ARRAY_DICT_INIT;
     ADD(errval, INTEGER_OBJ((Integer)i));
     ADD(errval, INTEGER_OBJ(nested_error.type));