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AgentCompany/builtin-skills/software-engineer/clean-code/references/class-cohesion.md
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ZacharyZhang-NY e74dafcd36 Silence render-disposed spam, unbreak bundled skills, drop board wake
Three independently ugly bugs that all fed the same log flood:

* Electron's `WebFrameMain.send` writes every "Render frame was disposed"
  to stderr via `console.error`. When the worker fans a second
  agent-event past a reloading renderer, we produced thousands of
  identical lines and stalled the main loop on stderr I/O. Added a
  `mainFrame.detached` guard so the send is short-circuited before
  Electron's own catch block fires, and installed a targeted filter in
  `suppress-warnings.ts` (now actually imported from the entry point)
  so the specific `console.error("Error sending from webFrameMain:"…)`
  noise never reaches the terminal. Any other payload still surfaces.

* `dispatchAgentMessage` accepted the human-reader sentinel as a wake
  target when an agent replied to `__board__` — `wakeAgentIfPossible`
  then called `db.getAgent("__board__")`, threw, and the dispatcher
  kept repeating on every send. Strip `HUMAN_SENDER_ID` at
  `resolveMessageWakeTargets`, and keep a defense-in-depth guard in the
  heartbeat so a stray caller (future automation fan-out) cannot
  reintroduce the crash.

* Pi's skills loader rejects any SKILL.md whose frontmatter `name`
  diverges from its parent directory. The four bundled `my-writing-style`
  copies declared `name: writing-style-skill`, so every install emitted
  a warning and dropped the skill. They also lived as orphan gitlinks
  (mode 160000 without .gitmodules), and the global `*.md` gitignore
  hid every other SKILL.md from version control. Fixed the frontmatter
  to match the dir, converted the dangling submodules to plain trees,
  and allowlisted `builtin-skills/**/*.md` so a fresh clone carries the
  catalogue instead of silently losing it.
2026-04-20 08:13:48 -04:00

2.0 KiB

title, impact, impactDescription, tags
title impact impactDescription tags
Maintain Class Cohesion MEDIUM enables extracting focused subclasses class, cohesion, variables, methods

Maintain Class Cohesion

Classes should have a small number of instance variables. Each method should manipulate one or more of those variables. The more variables a method manipulates, the more cohesive the method is to its class.

Incorrect (low cohesion - methods use different variables):

public class Utility {
    private Database db;
    private EmailService email;
    private Logger logger;
    private Cache cache;

    public void saveUser(User user) {
        db.save(user);  // Only uses db
        logger.log("Saved user");  // Only uses logger
    }

    public void sendNotification(String message) {
        email.send(message);  // Only uses email
    }

    public Object getCached(String key) {
        return cache.get(key);  // Only uses cache
    }
}
// Each method uses different instance variables - low cohesion

Correct (high cohesion - methods use shared variables):

public class Stack {
    private int topOfStack = 0;
    private List<Integer> elements = new LinkedList<>();

    public int size() {
        return topOfStack;  // Uses topOfStack
    }

    public void push(int element) {
        topOfStack++;  // Uses topOfStack
        elements.add(element);  // Uses elements
    }

    public int pop() throws EmptyStackException {
        if (topOfStack == 0)
            throw new EmptyStackException();
        int element = elements.get(--topOfStack);  // Uses both
        elements.remove(topOfStack);  // Uses both
        return element;
    }
}
// Every method uses the same instance variables - high cohesion

When cohesion breaks down: If a subset of methods only uses a subset of variables, extract those methods and variables into a separate class.

Reference: Clean Code, Chapter 10: Classes