feat(cli): add flash update command with passive update check

[deanq]

Summary

• Add flash update command for self-updating runpod-flash to latest or a specific version via PyPI
• Prefer uv pip install when uv is on PATH, fall back to python -m pip install otherwise
• Add passive background update check that runs on CLI invocation (at most once per 24h, cached to disk) and prints a one-line stderr notice if a newer version exists
• Background check excluded from flash run (long-running), flash update (already managing versions), and CI/headless environments

Test plan

• Run flash update -- verify it checks PyPI and reports current version
• Run flash update --version 1.4.0 -- verify it installs specific version (uses uv)
• Run flash build --help -- verify passive check triggers (inspect ~/.config/runpod/update_check.json)
• Run flash run --help -- verify passive check does NOT trigger
• Set FLASH_NO_UPDATE_CHECK=1 and run any command -- verify check is skipped
• All 1307 tests pass, 74.18% coverage

[Copilot]

Pull request overview

Adds a self-update flow to the Flash CLI along with a passive, cached update notification that runs in the background on most CLI invocations.

Changes:

• Introduces flash update command to install the latest (or a specified) runpod-flash version from PyPI.
• Adds a passive background update checker with a 24h on-disk cache and an atexit notice on stderr when a newer version is available.
• Wires the background checker into the CLI entrypoint while excluding flash run and flash update.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/runpod_flash/cli/commands/update.py	New flash update command plus helper functions for PyPI lookup and pip install.
src/runpod_flash/cli/update_checker.py	New background update-checker module with disk cache + atexit notice.
src/runpod_flash/cli/main.py	Registers the new update command and triggers the passive update check for most subcommands.
tests/unit/cli/commands/test_update.py	Unit/integration-style tests for flash update behavior.
tests/unit/cli/test_update_checker.py	Unit tests for caching, background check behavior, and notice printing.

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[deanq]

Re: no-subcommand / --help / --version skipping the check (comment on main.py:97)

Intentional. The no-subcommand path only renders the welcome panel and exits — there's no meaningful work for the check to overlap with, and the notice would print immediately after the panel (odd UX). Same for --version which raises typer.Exit() before the check. The gating stays as-is; I'll clarify the PR description.

Addressing the other 4 items in code:

• _fetch_pypi_metadata: catch JSONDecodeError/KeyError/UnicodeDecodeError and re-raise as RuntimeError
• _run_check: treat missing/empty latest_version in fresh cache as stale (fall through to fetch)
• start_background_check: skip when neither stdout nor stderr is a TTY
• start_background_check: add idempotency guard to prevent duplicate threads/atexit handlers

[deanq]

All 5 review items addressed in 3e4af42:

1. main.py:97 (no-subcommand skip) — Intentional by design. No-args shows the welcome panel and exits immediately; --version raises typer.Exit() before the check. Neither has meaningful work to overlap with.

2. update.py:58 (JSON/key errors) — Fixed. _fetch_pypi_metadata now catches JSONDecodeError, UnicodeDecodeError, and KeyError, re-raising as RuntimeError with user-friendly messages.

3. update_checker.py:100 (missing latest_version in fresh cache) — Fixed. Missing or empty latest_version in a fresh cache is now treated as stale, falling through to a PyPI fetch.

4. update_checker.py:143 (non-TTY skip) — Fixed. Added _is_interactive() helper; skips when neither stdout nor stderr is a TTY.

5. update_checker.py:147 (idempotency) — Fixed. Added _started flag with _start_lock so start_background_check() only runs once per process.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

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[runpod-Henrik]

Code Review — PR #237: flash update + background update checker

Clean implementation. Three issues found:

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Bug 1 (HIGH): uv pip install fails without active venv

update.py — _build_install_command()

if shutil.which("uv"):
    return ["uv", "pip", "install", package_spec, "--quiet"]

uv pip install requires an active venv (VIRTUAL_ENV set or .venv discoverable). If flash is installed system-wide and uv is on PATH, this fails with exit code 2. The pip fallback works correctly because it uses sys.executable.

Fix: Pass --python sys.executable:

return ["uv", "pip", "install", "--python", sys.executable, package_spec, "--quiet"]

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Bug 2 (MEDIUM): _started = True set before env-var guards — permanently disables update checks

update_checker.py — start_background_check()

with _start_lock:
    if _started:
        return
    _started = True      # <-- set HERE

if os.getenv("FLASH_NO_UPDATE_CHECK"):
    return               # _started=True, no thread started, no atexit

If called with CI=1 or FLASH_NO_UPDATE_CHECK=1, _started becomes True but no thread/atexit is registered. If the env var is later cleared (test suites), subsequent calls are silently no-oped. Move _started = True to after the guards, just before thread.start().

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Bug 3 (LOW): _parse_version crashes on PEP 440 pre-release versions

update.py — _parse_version()

return tuple(int(part) for part in version.split("."))

PyPI info.version can be 1.5.0rc1 or 1.5.0a1. int("0rc1") raises ValueError. In update_command the except ValueError: pass handles it, but in update_checker._run_check() the bare except Exception: pass silently skips the entire comparison — no update notice is printed even if a newer stable version exists.

Fix: Use packaging.version.Version (already a transitive dep):

from packaging.version import Version
def _parse_version(version: str) -> Version:
    return Version(version)

[runpod-Henrik]

Follow-up review by Henrik's AI-Powered Bug Finder

Checked ed1c2e3 against our three original items:

Bug 2 (_started flag): FIXED

_started = True now set after all skip checks, inside the lock. Thread start + atexit.register also moved inside the lock — cleaner than before. Good.

Bug 3 (_parse_version): MITIGATED

_compare_versions() with zero-padding handles the tuple-length edge case ((2, 0) == (2, 0, 0)). 8 solid test cases. However, _parse_version("1.5.0rc1") still raises ValueError — the except Exception: pass in _run_check() swallows it, so users on a pre-release version get no update notice for the next stable release. Low priority, but worth a note.

Bug 1 (uv pip install without venv): STILL OPEN — follow-up item

_build_install_command() still runs bare uv pip install which requires an active venv. If flash is installed system-wide and uv is on PATH, this fails with exit code 2. Not blocking since the error message is clear and flash update is non-critical. Fix for follow-up: ["uv", "pip", "install", "--python", sys.executable, ...]

Bonus fixes

• /proc test path → monkeypatch (cross-platform)
• Missing newline in update notice output
• Both well done.

Approving — Bug 2 fix was the important one and it's solid. Bug 1 is a minor edge case suitable for a follow-up PR.

🤖 Reviewed by Henrik's AI-Powered Bug Finder