バグレポート

よく、こんなバグを見つけましたと言って、バグが再現しない条件と再現する条件の境界を綿密に調べて報告してくださるお客がある。でも、大抵、そういうのは意味ないんですよね。バグが再現するコード（ケース）を一つ送って頂ければオーケー。
GDB の本にも書いてあります。

Here are some things that are not necessary:
A description of the envelope of the bug. Often people who encounter a bug spend a lot of time investigating which changes to the input file will make the bug go away and which changes will not affect it. This is often time consuming and not very useful, because the way we will find the bug is by running a single example under the debugger with breakpoints, not by pure deduction from a series of examples. We recommend that you save your time for something else.