ALL-HIST0002 · file_too_many_hands_have_touched

Count files spread across so many authors that nobody can answer for them.

This is a deterministic rule for all languages. Read its implementation.

Definition

Report a file at least minimum_authors distinct people changed across at least minimum_commits commits. A file one person keeps has a reader who knows why every line is there. A file eight people have each visited twice has none, and the next question about it goes unanswered or gets answered wrongly. Structure cannot see this at all, because the code reads exactly the same whoever wrote it.

The commit floor is what keeps the measure about spread rather than about age. A file six people touched in six commits is genuinely shared, while one that three people touched once each during a repository wide rename never had an owner to lose.

Evidence

Each finding names the file, how many distinct authors changed it, and how many commits they changed it in. The value is the number of files above both floors.

Exceptions

A manifest, a changelog, and a dependency lock are meant to be edited by everyone and say nothing about ownership, so a project keeping them under this scan raises the floors or excludes them. A repository with fewer contributors than minimum_authors reports nothing, which is the correct answer rather than a miss. A long lived project loses authors to time, so a narrower history window measures who owns it now instead of who ever did.

Examples

Bad

A `settings` module that nine people changed across forty commits. Each of them added the one
option their feature needed, nobody removed anything, and no one can now say which options are
still read.

Good

A settings module that one person changed across forty commits. It is just as busy, and there is somebody who can say what every option is for.

References

• Cites “Software Design X-Rays”, chapter 7, knowledge distribution and off-boarding risk
• Cites “Your Code as a Crime Scene”, chapter 9, code as a crime scene of many hands
• Cites “Don’t Touch My Code”, FSE 2011. Open reference