alt Hacker NewsThe actual thing you'd attack with a hash collision is the blob object, not the tree object, right? The tree object has a rigid structure and git will throw a fit if you add non-functional data to modify its hash. Source code files have comments which make it much easier to manipulate the hash.
you're right, i worded that poorly. what i meant to imply was that a blob hash collision causes any tree referencing it to be malicious, which cascades down to many different commits/tags (potentially all of them, if the tree is untouched since repo creation).