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AgentCompany/builtin-skills/software-engineer/clean-code/references/func-one-thing.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

2.5 KiB

title, impact, impactDescription, tags
title impact impactDescription tags
Functions Should Do One Thing CRITICAL enables understanding functions at a glance func, single-responsibility, cohesion, focus

Functions Should Do One Thing

Functions should do one thing. They should do it well. They should do it only. If a function does multiple things, extract those things into separate functions.

Incorrect (function does multiple things):

public void processEmployee(Employee employee) {
    // Validate employee
    if (employee.getName() == null || employee.getName().isEmpty()) {
        throw new IllegalArgumentException("Name required");
    }
    if (employee.getSalary() < 0) {
        throw new IllegalArgumentException("Salary cannot be negative");
    }

    // Calculate tax
    double tax = employee.getSalary() * 0.3;
    employee.setTax(tax);

    // Save to database
    Connection conn = getConnection();
    PreparedStatement stmt = conn.prepareStatement(
        "INSERT INTO employees VALUES (?, ?, ?)");
    stmt.setString(1, employee.getName());
    stmt.setDouble(2, employee.getSalary());
    stmt.setDouble(3, tax);
    stmt.execute();

    // Send email notification
    EmailService.send(employee.getEmail(), "Welcome!");
}

Correct (each function does one thing):

public void processEmployee(Employee employee) {
    validateEmployee(employee);
    calculateTax(employee);
    saveEmployee(employee);
    sendWelcomeEmail(employee);
}

private void validateEmployee(Employee employee) {
    validateName(employee);
    validateSalary(employee);
}

private void calculateTax(Employee employee) {
    double tax = employee.getSalary() * TAX_RATE;
    employee.setTax(tax);
}

private void saveEmployee(Employee employee) {
    employeeRepository.save(employee);
}

private void sendWelcomeEmail(Employee employee) {
    emailService.sendWelcome(employee.getEmail());
}

Test: If you can extract another function from it with a name that is not merely a restatement of its implementation, the function is doing more than one thing.

When NOT to split:

  • If the extracted function's name would just restate its body (e.g., calculateTax containing only salary * TAX_RATE), the extraction adds indirection without clarity.
  • Orchestration functions that call a sequence of steps at the same abstraction level (like processEmployee above) are doing "one thing" — orchestrating. Don't try to extract the orchestration further.

Reference: Clean Code, Chapter 3: Functions