4.2.2 Unnecessary information

Here are some things that are not necessary to include in a bug report.

• 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 or command-line options 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. You might as well save your time for something else.

• A patch for the bug.

  A patch for the bug is useful if it is a good one. But don't omit the necessary information, such as the test case, on the assumption that a patch is all we need. We might see problems with your patch and decide to fix the problem another way, or we might not understand the patch at all. Without an example, we won't be able to verify that the bug is fixed.

  Also, if we can't understand what bug you are trying to fix, or why your patch should be an improvement, we won't install it. A test case will help us to understand.

  See section `Sending Patches for GNU CC' in GCC Manual, for more details on the best way to write changes.

• Sometimes people send just a backtrace, but that is not useful by itself. It is usually the values of local or global variables which matter, sometimes very far away from the location where you noticed the bug. We need to be able to run the debugger ourselves to investigate.

• A guess about what the bug is or what it depends on.

  Such guesses are not useful, and often wrong. It is impossible to guess correctly without using the debugger to find the facts, so you might as well save your imagination for other things!