api: do not free dynamic string on error in function string_dyn_concat

CHANGELOG.md

@@ -11,6 +11,7 @@
 - core: fix possible buffer overflow in command /color alias ([#2330](https://github.com/weechat/weechat/issues/2330))
 - core: fix possible buffer overflow in list of commands displayed by /help ([#2330](https://github.com/weechat/weechat/issues/2330))
 - core: fix buffer overflow in connection to SOCKS5 proxy ([#2325](https://github.com/weechat/weechat/issues/2325))
+- api: do not free dynamic string on error in function string_dyn_concat
 - api: fix infinite loop in function string_replace when the search string is empty
 - irc: limit size of data received from the server to prevent memory exhaustion
 - irc: fix out-of-bounds read on incoming DCC command with a quoted filename ending the message ([#2322](https://github.com/weechat/weechat/issues/2322))

doc/en/weechat_plugin_api.en.adoc

@@ -3470,6 +3470,8 @@ Concatenate a string to a dynamic string.
 The pointer _*string_ can change if the string is reallocated (if there is
 not enough space to concatenate the string).
 
+In case of error, the dynamic string is left unchanged.
+
 Prototype:
 
 [source,c]

doc/fr/weechat_plugin_api.fr.adoc

@@ -3528,6 +3528,8 @@ Concaténer une chaîne dans une chaîne dynamique.
 Le pointeur _*string_ peut changer si la chaîne est réallouée (s'il n'y a pas
 assez de place pour concaténer la chaîne).
 
+En cas d'erreur, la chaîne dynamique reste inchangée.
+
 Prototype :
 
 [source,c]

doc/it/weechat_plugin_api.it.adoc

@@ -3635,6 +3635,9 @@ Concatenate a string to a dynamic string.
 The pointer _*string_ can change if the string is reallocated (if there is
 not enough space to concatenate the string).
 
+// TRANSLATION MISSING
+In case of error, the dynamic string is left unchanged.
+
 Prototipo:
 
 [source,c]

doc/ja/weechat_plugin_api.ja.adoc

@@ -3585,6 +3585,9 @@ _WeeChat バージョン 1.8 以上で利用可, updated in 3.0_
 文字列が再確保された場合 (文字列を連結するのに十分なサイズが確保されていなかった場合)
 にはポインタ _*string_ が変わる可能性があります。
 
+// TRANSLATION MISSING
+In case of error, the dynamic string is left unchanged.
+
 プロトタイプ:
 
 [source,c]

doc/sr/weechat_plugin_api.sr.adoc

@@ -3355,6 +3355,9 @@ _WeeChat ≥ 1.8, ажурирано у верзији 3.0._
 
 Показивач на стринг _*string_ може да се промени ако се стринг реалоцира (у случају да нема довољно простора за надовезивање стринга).
 
+// TRANSLATION MISSING
+In case of error, the dynamic string is left unchanged.
+
 Прототип:
 
 [source,c]

src/core/core-string.c

@@ -4759,6 +4759,8 @@ string_dyn_copy (char **string, const char *new_string)
  * if the string had to be extended, or the same pointer if there was enough
  * size to concatenate the new string.
  *
+ * In case of error, the dynamic string is left unchanged.
+ *
  * Returns:
  *   1: OK
  *   0: error
@@ -4794,11 +4796,7 @@ string_dyn_concat (char **string, const char *add, int bytes)
             new_size_alloc = new_size;
         string_realloc = realloc (ptr_string_dyn->string, new_size_alloc);
         if (!string_realloc)
-        {
-            free (ptr_string_dyn->string);
-            free (ptr_string_dyn);
             return 0;
-        }
         ptr_string_dyn->string = string_realloc;
         ptr_string_dyn->size_alloc = new_size_alloc;
     }