In the try_merge_strategy function the expression in the following if statement seems to always evaluate to TRUE:
if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
If strategy is "recursive" then !strcmp(strategy, "subtree") evaluates to TRUE.
If strategy is "subtree" then !strcmp(strategy, "recursive") evaluates to TRUE.
If strategy is neither "recursive" nor "subtree" then any side of || evaluates to TRUE.
Looks like the code in the else block is unreachable?
Saša Živkov