player/loadfile.c

@@ -1534,7 +1534,7 @@ static void append_to_watch_history(struct MPContext *mpctx)
     FILE *history_file = fopen(history_path, "ab");
 
     if (!history_file) {
-        MP_ERR(mpctx, "Failed to write to %s: %s\n", history_path,
+        MP_ERR(mpctx, "Failed to open history file: %s\n",
                mp_strerror(errno));
         goto done;
     }
@@ -1571,12 +1571,31 @@ static void append_to_watch_history(struct MPContext *mpctx)
     json_write(&dst, &node);
     dst = talloc_strdup_append(dst, "\n");
 
-    bool failed = fwrite(dst, strlen(dst), 1, history_file) != 1;
-    if (fclose(history_file) || failed) {
-        MP_ERR(mpctx, "Failed to write to %s: %s\n", history_path,
+    long history_size = ftell(history_file);
+    if (history_size == -1) {
+        MP_ERR(mpctx, "Failed to get history file size: %s\n",
+                mp_strerror(errno));
+        fclose(history_file);
+        goto done;
+    }
+
+    bool failed = fwrite(dst, strlen(dst), 1, history_file) != 1 &&
+                  fflush(history_file) != 0;
+
+    if (failed) {
+        MP_ERR(mpctx, "Failed to write to history file: %s\n",
                mp_strerror(errno));
+
+        int fd = fileno(history_file);
+        if (fd == -1 || ftruncate(fd, history_size) == -1)
+            MP_ERR(mpctx, "Failed to roll-back history file: %s\n",
+                   mp_strerror(errno));
     }
 
+    if (fclose(history_file) != 0)
+        MP_ERR(mpctx, "Failed to close history file: %s\n",
+               mp_strerror(errno));
+
 done:
     talloc_free(ctx);
 }