Maintaining fine-grained code metadata regardless of moving, copying and merging

Source code metadata on a file-level granularity is too coarse for certain applications. But fine-grained metadata (e.g. line-by-line authorship) easily gets lost due to changes like merging, moving or copying code. Enabling metadata to survive code evolution provides valuable insights into program source code. This helps developers to understand the sources and opens up opportunities for advanced tools. We present a concept that utilizes different search heuristics to identify probable ancestors of source documents, and pair this with clone detection to locate origins of inserted code. Arbitrary kinds of metadata can then be linked to code sections and be preserved automatically while code evolves. We evaluate our approach using code from the Hydra and FreeCol projects, and sketch prospective applications.