The contents of files are basically hashed, if the contents don't change of the file listed for a target then no change will happen, even if you modify metadata

The contents of files are basically hashed, if the contents don't change of the file listed for a target then no change will happen, even if you modify metadata of the file (like last modified time by `touch` or so on.) Bazel is really sophisticated and I'd be lying if I said I understood it well, but I have spent time looking at it.