Leak when iterating through commits and diff them

When I run the code below on a production repository, i can see that the memory is all the time increasing and after about 3000 commits my pc crashes with out of memory.

For about 1000 commit it reserved about 500 MB Ram.

Code for Testsetup see here:
https://gist.github.com/Gentlehag/9f595ab13f459e22859fa5d9557e550b

PS: I also posted here:
http://stackoverflow.com/questions/39258639/possible-leak-when-reading-content

My target is to just iterate through all commits and getting all files that were changed in eahc commit.

Is there a better way ? Is this a bug?

首先執行 issue 的 GitHub Gist 中連結的重現，並在逐一處理提交和 diff 時觀察記憶體。將行為與 Stack Overflow 討論進行比較，接著確認洩漏是在提交迭代中還是在 diff 處理中；完成的標準是重現增長現象，並確立經過驗證的修正方案或有文件記錄的替代方案。