Undefined std::vector access in Bag::readRecords

[kya8]

embag/lib/embag.cc

Lines 168 to 169 in 74c0b5f

	chunk_infos_.reserve(chunk_count);
	chunks_.reserve(chunk_count);

Both chunk_infos_ and chunks_ were reserve()'d, then accessed without initializing, which is undefined.

For chunk_infos_:

embag/lib/embag.cc

Line 243 in 74c0b5f

chunk_infos_[i] = chunk_info;

And &chunks_[i] was accessed before the element was pushed:

embag/lib/embag.cc

Lines 288 to 296 in 74c0b5f

	index_block.into_chunk = &chunks_[i];
	info.message_count += msg_count;
	connections_[connection_id].blocks.push_back(index_block);
	connections_[connection_id].data.message_count += msg_count;
	}
	chunk.info = info;
	chunks_.push_back(chunk);

It does happen to work on MSVC Release build, but a "vector subscription out of range" exception was emitted in Debug build.