Bug fingerprinting для UI: почему stack trace не работает и что вместо

• Тип исключения (TypeError, NullPointerException)
  
• Top frame stack trace (module.py:42 → user_handler)
  
• Транзитивно — содержание top функции

Error: expect(locator).toBeVisible() failed
Locator: getByRole('button', { name: 'Place Order' })
Expected: visible
Actual: not found
URL: https://shop.example.com/checkout

• Что мы искали — locator (getByRole('button', { name: 'Place Order' }))
  
• Что мы проверяли — assertion (toBeVisible, toHaveText, toHaveURL)
  
• Тип ошибки — class (TimeoutError, AssertionError)
  
• Где — URL pattern (без волатильных частей)
  
• Содержание — short snippet of error message

fingerprint = sha256(f"{selector}|{assertion}|{error_class}|{url}|{message}")[:8]

getByRole('button').nth(2)  // i.e. nth-child(3) in DOM

getByRole('button').nth(3)  // i.e. nth-child(4) in DOM

URL: /run/abc123de-1234-1234-1234-123456789abc/details

URL: /users/12345/profile

URL: /search?q=foo&utm_source=test&_=1715693845

import re
import hashlib
SELECTOR_NORMS = [
    (re.compile(r":nth-child\(\d+\)"),   ":nth-child"),
    (re.compile(r":nth-of-type\(\d+\)"), ":nth-of-type"),
]
URL_NORMS = [
    # UUIDs (любая позиция)
    (re.compile(r"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", re.I),
     ":uuid"),
    # Числовые ID между слешами
    (re.compile(r"/\d+(?=/|$|\?)"), "/:id"),
    # Query strings — целиком
    (re.compile(r"\?.*$"), ""),
]
def normalize_selector(s: str) -> str:
    for pat, repl in SELECTOR_NORMS:
        s = pat.sub(repl, s)
    return s
def normalize_url(url: str) -> str:
    if not url:
        return ""
    # Stripping protocol+host если есть
    m = re.match(r"^https?://[^/]+(.*)", url)
    path = m.group(1) if m else url
    for pat, repl in URL_NORMS:
        path = pat.sub(repl, path)
    return path
def compute_fingerprint(bug: dict) -> str:
    err = bug.get("error") or {}
    msg = (err.get("message") or "")[:120]
    selector = normalize_selector(bug.get("selector", ""))
    assertion = bug.get("assertion_type", "Generic")
    error_class = bug.get("error_class", "AssertionError")
    url_path = normalize_url(err.get("url") or "")
    composite = f"{selector}|{assertion}|{error_class}|{url_path}|{msg[:80]}"
    return hashlib.sha256(composite.encode("utf-8")).hexdigest()[:8]

def extract_selector(error_snippet: str, error_msg: str) -> str:
    haystack = (error_snippet or "") + " " + (error_msg or "")
    for prefix in ("getByRole", "getByLabel", "getByText", "getByTestId",
                   "getByPlaceholder", "getByAltText", "getByTitle", "locator"):
        m = re.search(rf"{prefix}\([^)]+\)", haystack)
        if m:
            return m.group(0)
    return ""
def extract_assertion_type(msg: str) -> str:
    for kw in ("toBeVisible", "toHaveText", "toHaveURL", "toHaveTitle",
               "toHaveAttribute", "toContainText", "toEqual", "toBe"):
        if kw in msg:
            return kw
    if re.search(r"timeout|Timeout", msg):
        return "Timeout"
    return "Generic"
def extract_error_class(msg: str) -> str:
    m = re.match(r"^([A-Z][A-Za-z]+(Error|Exception)):", msg)
    if m:
        return m.group(1)
    if re.search(r"timeout|Timeout", msg):
        return "TimeoutError"
    return "AssertionError"

def diff_runs(current: list[dict], previous: list[dict]) -> dict:
    prev_map = {b.get("fingerprintHash"): b for b in previous if b.get("fingerprintHash")}
    summary = {"new": 0, "regression": 0, "persisting": 0, "fixed": 0}
    out = []
    cur_hashes = set()
    for bug in current:
        fp = bug["fingerprintHash"]
        cur_hashes.add(fp)
        prev = prev_map.get(fp)
        if prev is None:
            state = "new"
        elif (prev.get("diff") or {}).get("state") == "fixed":
            state = "regression"  # был fixed, вернулся
        else:
            state = "persisting"
            bug["occurrenceCount"] = (prev.get("occurrenceCount") or 1) + 1
        bug["diff"] = {
            "state": state,
            "previousRunId": prev.get("lastSeenRunId") if prev else None,
        }
        summary[state] += 1
        out.append(bug)
    # Newly fixed: present in previous, absent in current
    for fp, prev in prev_map.items():
        if fp in cur_hashes:
            continue
        if (prev.get("diff") or {}).get("state") == "fixed":
            continue  # already fixed earlier — не считаем "newly"
        prev_copy = dict(prev)
        prev_copy["diff"] = {"state": "fixed", "previousRunId": prev.get("lastSeenRunId")}
        out.append(prev_copy)
        summary["fixed"] += 1
    return {"bugs": out, "summary": summary}

• new — fingerprint не было в предыдущем прогоне
  
• persisting — был, всё ещё есть; счётчик occurrence инкрементится
  
• fixed — был в предыдущем, в текущем отсутствует, и НЕ был помечен fixed раньше
  
• regression — был, был помечен fixed, потом вернулся

def severity_from_signals(bug: dict) -> str:
    issue_line = (bug.get("issueLine") or "").lower()
    # axe-core impact → severity
    if "a11y[critical]" in issue_line or "a11y[serious]" in issue_line:
        return "S1"
    if "a11y[moderate]" in issue_line:
        return "S2"
    if "a11y[minor]" in issue_line:
        return "S3"
    # Структурные теги от spec template
    if issue_line.startswith("heading-jump:"):     return "S2"
    if issue_line.startswith("touch-target:"):     return "S2"
    if issue_line.startswith("overflow:"):         return "S1"
    # Heuristic match на keywords из title + error
    text = (bug.get("title", "") + " " + bug.get("error", {}).get("message", "")).lower()
    if any(k in text for k in ["auth", "login", "checkout", "payment", "5xx"]):
        return "S0"
    if any(k in text for k in ["uncaught", "hydration"]):
        return "S0"
    return "S2"  # default

// @severity: S0
test('checkout completely broken', async ({ page }) => { /* ... */ });

{
  "runId": "run-2026-04-30-1430",
  "bugs": [
    {
      "id": "BUG-a3f9c2b1",
      "fingerprintHash": "a3f9c2b1",
      "title": "Checkout 'Place Order' button non-functional on mobile",
      "severity": "S0",
      "priority": "P0",
      "diff": { "state": "regression", "previousRunId": "run-2026-04-26-0902" },
      "occurrenceCount": 3,
      "trackerMappings": {
        "linear": { "priority": 1 },
        "github": { "labels": ["bug", "severity/s0", "priority/p0"] },
        "jira":   { "issueType": "Bug", "priorityName": "Highest" }
      }
    }
  ]
}

• webtest-orch — Claude Code skill для e2e-тестирования, использует этот fingerprint
  
• Sentry grouping docs — оригинальный backend-подход на котором этот UI-вариант построен по аналогии
  
• Playwright locator priority — почему getByRole идёт первым в нашем extractor