From e309e221f7363addbee4462ddbb8c10b6abe7839 Mon Sep 17 00:00:00 2001
From: Hannes Winkler <hanneswinkler2000@web.de>
Date: Mon, 16 Sep 2024 21:17:33 +0000
Subject: [PATCH] try another source code permutation to fix analyzer warnings

---
 src/pluginregistry.c | 37 +++++++++++++++++++++----------------
 src/util/list.h      |  9 +++------
 2 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/src/pluginregistry.c b/src/pluginregistry.c
index de51cb80..f78b917b 100644
--- a/src/pluginregistry.c
+++ b/src/pluginregistry.c
@@ -91,13 +91,11 @@ static struct plugin_instance *get_plugin_by_name(struct plugin_registry *regist
 
 // clang-format off
 static struct platch_obj_cb_data *get_cb_data_by_channel_locked(struct plugin_registry *registry, const char *channel) {
-    ANALYZER_SUPPRESS({
-        list_for_each_entry(struct platch_obj_cb_data, data, &registry->callbacks, entry) {
-            if (streq(data->channel, channel)) {
-                return data;
-            }
+    list_for_each_entry(struct platch_obj_cb_data, data, &registry->callbacks, entry) {
+        if (streq(data->channel, channel)) {
+            return data;
         }
-    });
+    }
 
     return NULL;
 }
@@ -396,17 +394,24 @@ int plugin_registry_set_receiver(const char *channel, enum platch_codec codec, p
 int plugin_registry_remove_receiver_v2_locked(struct plugin_registry *registry, const char *channel) {
     struct platch_obj_cb_data *data;
 
-    // clang analyzer reports false-positives for using deallocated memory here.
-    ANALYZER_SUPPRESS({
-        data = get_cb_data_by_channel_locked(registry, channel);
-        if (data == NULL) {
-            return EINVAL;
-        }
+    data = get_cb_data_by_channel_locked(registry, channel);
+    if (data == NULL) {
+        return EINVAL;
+    }
+
+    list_del(&data->entry);
+
+    // Analyzer thinks get_cb_data_by_channel might still return our data
+    // after list_del and emits a "use-after-free" warning.
+    // assert()s can change the assumptions of the analyzer, so we use them here.
+#ifdef DEBUG
+    list_for_each_entry(struct platch_obj_cb_data, data_iter, &registry->callbacks, entry) {
+        ASSUME(data_iter != data);
+    }
+#endif
 
-        list_del(&data->entry);
-        free(data->channel);
-        free(data);
-    });
+    free(data->channel);
+    free(data);
 
     return 0;
 }
diff --git a/src/util/list.h b/src/util/list.h
index a2ed892e..28440cd8 100644
--- a/src/util/list.h
+++ b/src/util/list.h
@@ -93,12 +93,9 @@ static inline void list_replace(struct list_head *from, struct list_head *to) {
 }
 
 static inline void list_del(struct list_head *item) {
-    // We need this to suppress a false positive `use-after-free` coming from pluginregistry.c.
-    ANALYZER_SUPPRESS({
-        item->prev->next = item->next;
-        item->next->prev = item->prev;
-        item->prev = item->next = NULL;
-    });
+    item->prev->next = item->next;
+    item->next->prev = item->prev;
+    item->prev = item->next = NULL;
 }
 
 static inline void list_delinit(struct list_head *item) {