Extend the "describe your changes well" section to cover whom we are trying to help by doing so in the first place. Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> --- Documentation/SubmittingPatches | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 7225a0fb52..a6121d1d42 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -110,6 +110,35 @@ run `git diff --check` on your changes before you commit. [[describe-changes]] === Describe your changes well. +The log message that explains your changes is just as important as the +changes themselves. Your code may be clearly written with in-code +comment to sufficiently explain how it works with the surrounding +code, but those who need to fix or enhance your code in the future +will need to know _why_ your code does what it does, for a few +reasons: + +. Your code may be doing something differently from what you wanted it + to do. Writing down what you actually wanted to achieve will help + them fix your code and make it do what it should have been doing + (also, you often discover your own bugs yourself, while writing the + log message to summarize the thought behind it). + +. Your code may be doing things that were only necessary for your + immediate needs (e.g. "do X to directories" without implementing or + even designing what is to be done on files). Writing down why you + excluded what the code does not do will help guide future developers. + Writing down "we do X to directories, because directories have + characteristic Y" would help them infer "oh, files also have the same + characteristic Y, so perhaps doing X to them would also make sense?". + Saying "we don't do the same X to files, because ..." will help them + decide if the reasoning is sound (in which case they do not waste + time extending your code to cover files), or reason differently (in + which case, they can explain why they extend your code to cover + files, too). + +The goal of your log message is to convey the _why_ behind your +change to help future developers. + The first line of the commit message should be a short description (50 characters is the soft limit, see DISCUSSION in linkgit:git-commit[1]), and should skip the full stop. It is also conventional in most cases to -- 2.35.0-177-g7d269f5170
