Change QUEUE_FOREACH macro to use while instead of for

src/nvim/eval.c

@@ -5289,10 +5289,10 @@ bool set_ref_in_item(typval_T *tv, int copyID, ht_stack_T **ht_stack,
 
         QUEUE *w = NULL;
         DictWatcher *watcher = NULL;
-        QUEUE_FOREACH(w, &dd->watchers) {
+        QUEUE_FOREACH(w, &dd->watchers, {
           watcher = tv_dict_watcher_node_data(w);
           set_ref_in_callback(&watcher->callback, copyID, ht_stack, list_stack);
-        }
+        })
       }
       break;
     }

src/nvim/eval/typval.c

@@ -1183,7 +1183,7 @@ bool tv_dict_watcher_remove(dict_T *const dict, const char *const key_pattern,
   QUEUE *w = NULL;
   DictWatcher *watcher = NULL;
   bool matched = false;
-  QUEUE_FOREACH(w, &dict->watchers) {
+  QUEUE_FOREACH(w, &dict->watchers, {
     watcher = tv_dict_watcher_node_data(w);
     if (tv_callback_equal(&watcher->callback, &callback)
         && watcher->key_pattern_len == key_pattern_len
@@ -1191,7 +1191,7 @@ bool tv_dict_watcher_remove(dict_T *const dict, const char *const key_pattern,
       matched = true;
       break;
     }
-  }
+  })
 
   if (!matched) {
     return false;
@@ -1265,7 +1265,7 @@ void tv_dict_watcher_notify(dict_T *const dict, const char *const key,
 
   dict->dv_refcount++;
   QUEUE *w;
-  QUEUE_FOREACH(w, &dict->watchers) {
+  QUEUE_FOREACH(w, &dict->watchers, {
     DictWatcher *watcher = tv_dict_watcher_node_data(w);
     if (!watcher->busy && tv_dict_watcher_matches(watcher, key)) {
       rettv = TV_INITIAL_VALUE;
@@ -1277,7 +1277,7 @@ void tv_dict_watcher_notify(dict_T *const dict, const char *const key,
         tv_dict_watcher_free(watcher);
       }
     }
-  }
+  })
   tv_dict_unref(dict);
 
   for (size_t i = 1; i < ARRAY_SIZE(argv); i++) {

src/nvim/event/multiqueue.c

@@ -119,8 +119,8 @@ static MultiQueue *multiqueue_new(MultiQueue *parent, put_callback put_cb,
 void multiqueue_free(MultiQueue *this)
 {
   assert(this);
-  while (!QUEUE_EMPTY(&this->headtail)) {
-    QUEUE *q = QUEUE_HEAD(&this->headtail);
+  QUEUE *q;
+  QUEUE_FOREACH(q, &this->headtail, {
     MultiQueueItem *item = multiqueue_node_data(q);
     if (this->parent) {
       QUEUE_REMOVE(&item->data.item.parent_item->node);
@@ -128,7 +128,7 @@ void multiqueue_free(MultiQueue *this)
     }
     QUEUE_REMOVE(q);
     xfree(item);
-  }
+  })
 
   xfree(this);
 }

src/nvim/lib/queue.h

@@ -33,11 +33,17 @@ typedef struct _queue {
 #define QUEUE_DATA(ptr, type, field) \
   ((type *)((char *)(ptr) - offsetof(type, field)))
 
-// Important note: mutating the list while QUEUE_FOREACH is
-// iterating over its elements results in undefined behavior.
-#define QUEUE_FOREACH(q, h) \
-  for (  /* NOLINT(readability/braces) */ \
-      (q) = (h)->next; (q) != (h); (q) = (q)->next)
+// Important note: the node currently being processed can be safely deleted.
+// otherwise, mutating the list while QUEUE_FOREACH is iterating over its
+// elements results in undefined behavior.
+#define QUEUE_FOREACH(q, h, code) \
+  (q) = (h)->next; \
+  while((q) != (h)) { \
+    QUEUE *next = q->next; \
+    code \
+    (q) = next; \
+  }
+
 
 // ffi.cdef is unable to swallow `bool` in place of `int` here.
 static inline int QUEUE_EMPTY(const QUEUE *const q)

src/nvim/os/pty_process_win.c

@@ -343,19 +343,17 @@ static int build_cmd_line(char **argv, wchar_t **cmd_line, bool is_cmdexe)
   utf8_cmd_line_len += argc;
   char *utf8_cmd_line = xmalloc(utf8_cmd_line_len);
   *utf8_cmd_line = NUL;
-  while (1) {
-    QUEUE *head = QUEUE_HEAD(&args_q);
-    QUEUE_REMOVE(head);
-    ArgNode *arg_node = QUEUE_DATA(head, ArgNode, node);
+  QUEUE *q;
+  QUEUE_FOREACH(q, &args_q, {
+    ArgNode *arg_node = QUEUE_DATA(q, ArgNode, node);
     xstrlcat(utf8_cmd_line, arg_node->arg, utf8_cmd_line_len);
     xfree(arg_node->arg);
     xfree(arg_node);
-    if (QUEUE_EMPTY(&args_q)) {
-      break;
-    } else {
+    QUEUE_REMOVE(q);
+    if (!QUEUE_EMPTY(&args_q)) {
       xstrlcat(utf8_cmd_line, " ", utf8_cmd_line_len);
     }
-  }
+  })
 
   int result = utf8_to_utf16(utf8_cmd_line, -1, cmd_line);
   xfree(utf8_cmd_line);