Fix potential leak found by cppcheck

[Irfy]

If realloc returns NULL, the original memory is untouched, and if not
otherwise needed, must be freed manually.

This pull request fixes this potential problem in theme.c

[Orc]

I'm not sure if this is important, because theme is a standalone program that processes one file, then quits. Can you elaborate on why you think that better gc is needed here?

[Irfy]

I supplied this patch only because of coding errors reported by [cppcheck][http://cppcheck.sourceforge.net/] in our project, without analyzing the impact of the error. If the code does as you say, then this fix probably won't have any real impact whatsoever.

However, leaving out all the frees in the code would just as well have no impact, but you have them -- it gives a false sense of robustness. The least that I'd suggest is to put a comment near the realloc, perhaps something like known to leak, but no real impact. Someone else using your code and running a static analysis tool over their codebase will then at least immediately know not to spend any time analyzing/fixing the realloc usage.

[hron84]

Or just simply put required free() calls. If omitting them has no real impact then putting them to right place affects same.
Even if they aren't required, it's a sign of professionality if you put them to the correct place. And static analysis tools will be happy too.

[Orc]

"...professionality..."

Spoken like someone who's never had to maintain code written by professional programmers.

[hron84]

Okay, try another aspect: merging this change can cause any problems in the current code or in future maintenance? I am just curious.