user-action-edge-caseslisted

## The rule Anything you depend on that a user can touch will get renamed, moved, deleted, and duplicated. If your code assumes a fixed path or a single copy, it breaks the first time the user does something ordinary. Before you finish, run those four actions through your head. ## Fires when Your code reads, writes, or depends on a file, an asset, a record, or any state the user can edit outside your code. ## How to apply For each thing you depend on, ask the four questions: renamed? moved? deleted? duplicated? Prefer finding things by type or id over a hardcoded path or name. Decide what happens in each case instead of assuming it won't happen. ## Worked example Your app stores its settings in a file at a hardcoded path. It works on your machine. Then a user renames the file, and the app silently writes a fresh one with defaults, losing their config. Or they copy the project folder, and now two copies fight over the same path. Looking the file up by a stable marker instead of a fixed name, and handling "not found" and "more than one" on purpose, turns four silent bugs into defined behavior. ## Red flags | Thought | Reality | |---|---| | "The file is always at this path" | Until the user moves it. | | "There's only ever one" | Until they duplicate it. | | "They won't rename it" | They will. |