bizarre crashing bug when assigning to StringTableEntry from data structure

#1

Quote:HEAP[FreeBuild_DEBUG.exe]: Heap block at 09219318 modified at 092193C4 past requested size of a4
Windows has triggered a breakpoint in FreeBuild_DEBUG.exe.

This may be due to a corruption of the heap, which indicates a bug in FreeBuild_DEBUG.exe or any of the DLLs it has loaded.

This may also be due to the user pressing F12 while FreeBuild_DEBUG.exe has focus.

The output window may have more diagnostic information.

[edit]

changing the problematic assignation to this:

//Overwriting a chunk of the heap or some bad stuff like that
		AssertFatal(fileSearchInfo.path != NULL && fileSearchInfo.name != NULL && !fileSearchInfo.subFile, "LDFileSearchInfo passed to LDParse::bufferFile() was for a sub-file, or was the result of a failed search");
		StringTableEntry filename;
		filename = NULL;
		filename = "toothpaste";
		filename = StringTable->insert("C:/Program Files (x86)/LDraw/PARTS/2531.dat");
		//  
		// Stepping over this line causes the program to crash.  
		// fileSearchInfo.path == filename already, after the last step, but the assignment crashes it.
        // 
		filename = fileSearchInfo.path;

Still causes the crash in the same place, namely when I try to assign the string from fileSearchInfo.path, but the debugger tells me it has the same contents as the string I assign immediately before that.

[edit #2]
Here is the code that instantiates fileSearchInfo:

LDFileSearchInfo * findLDrawFile(const char * filename, Vector<LDFileData*> &subfile_search_stack)
	{
		
		U32 i;
		U32 cacheDepth = gLDrawPrintCacheTree ? 0 : -1;
		StringTableEntry file = StringTable->insert(filename);
		
		LDCacheNode * cacheRoot = LDCacheNode::getRoot();
		LDCacheNode * subFileList = NULL;		
		LDCacheNode * cachedFile = NULL;
		LDFileSearchInfo * ret = new LDFileSearchInfo;
		ret->name = NULL;
		ret->path = NULL;
		ret->subFile = false;
		ret->file = NULL;
		
		U32 ldis = gLDrawInstallation.size();
		if(ldis % 3) {
			Con::errorf("findLDrawFile called before any entries in $pref::LDraw::Directory were validated. Please call checkLDrawDirectory()");
			
		} else if(!subfile_search_stack.empty()) for(i = 0; i < subfile_search_stack.size(); i++){
			subFileList = subfile_search_stack[i]->getSubfileCache();
			if((subFileList != NULL) && // Did we get passed some sub-files?
			   ((cachedFile = subFileList->find(file,cacheDepth)) != NULL) && // Is the file name among the sub-files?
			   (cachedFile->getContents() != NULL) // Is it really holding something?
			   ) {
				ret->name = file;
				ret->path = cachedFile->getContents()->getPath();
				ret->subFile = true;
				ret->file = cachedFile->getContents();
				break;
			}
		} 
		
		if(ret->name == NULL){
			if((cacheRoot != NULL) &&
			   ((cachedFile = cacheRoot->find(file,cacheDepth)) != NULL) && // Is the file name among the sub-files?
			   (cachedFile->getContents() != NULL) && // Is it really holding something?
			   (cachedFile->getContents()->hasCache() || cachedFile->getContents()->hasSubfiles()) // Have we cached it yet?
			   ) {
				ret->name = file;
				ret->path = cachedFile->getContents()->getPath();
				ret->file = cachedFile->getContents();
			} else {
				
				//Assumes a beginning->end traversal to ensure proper precedence.
				
				StringTableEntry path;
				char pReturn[1024];
				
				for(std::deque<std::string>::const_iterator itr = gLDrawInstallation.begin(); 
					itr!=gLDrawInstallation.end(); 
					++itr
					) {
					path = StringTable->insert(itr->c_str());
					Platform::makeFullPathName(file, pReturn, 1024, path);
					if(Platform::isFile(pReturn) && !Platform::isDirectory(pReturn)){
						ret->name = file;
						ret->path = StringTable->insert(pReturn);
						break;
					}
				}
				
				
			}
		}
		
		
		if(ret->name == NULL) Con::warnf("File '%s' not found in LDraw directories",file);
		return ret;
	}

#2 Nevermind, the debugger was lying to me. The stack trace after the crash would jump to an entirely different portion of code then the one I was stepping through when the crash occurred. I think I have it figured out.