git blame and git log -S are both granular tools with their own blindspots. To actually get to the bottom of something you need a higher level tool which lets

git blame and git log -S are both granular tools with their own blindspots. To actually get to the bottom of something you need a higher level tool which lets you iterate through historical changes across multiple files over time. The workflow is 1) git blame problematic area 2) open full commit + diff for that change so you can see context 3) open relevant file(s) as they existed in that commit 4) repeat steps 1,2 and 3 until you get to root cause. This workflow is not subject to any limitations around code structure, variable naming, file moving or anything else. fugitive.vim is a plugin which lets you very quickly recurse into history in this fashion using multiple vim windows.