feat(logs): раздел «Логи» — хвост и свой grep (#16)

- app/logs/grep.py: подмножество grep (шаблон, -i -v -E -c -C N), разбор
  shlex без исполнения, BRE → regex, таймаут на строку и бюджет на поиск,
  лимиты 200 символов / 500 строк вывода
- app/logs/journal.py: каждый поиск в log_queries (L-6)
- бот: выбор контейнера, хвост 50/200 строк или 5 мин/1 ч/24 ч, свой grep
  по 24 ч, длинный результат — файлом .log (L-5)
- логи Docker: не больше 50 000 строк и 5 МБ, сохраняются новейшие
- fix: кнопки меню и /menu, /help больше не проглатываются шагами ввода
  (имя файла, содержимое, сообщение коммита, grep) — фильтр free_input

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/logs/test_grep.py

@@ -0,0 +1,151 @@
+import time
+
+import pytest
+
+from app.logs.grep import (
+    MAX_PATTERN,
+    GrepError,
+    GrepErrorCode,
+    GrepQuery,
+    bre_to_ere,
+    parse_grep,
+    run,
+    to_command,
+)
+
+LOG = "\n".join(
+    [
+        "08:00 start",
+        "08:01 connect db",
+        "08:02 ERROR connection refused",
+        "08:03 retry",
+        "08:04 ok",
+        "08:05 idle",
+        "08:06 idle",
+        "08:07 error: timeout",
+        "08:08 done",
+    ]
+)
+
+
+@pytest.mark.parametrize(
+    ("expr", "expected"),
+    [
+        ("error", GrepQuery("error")),
+        ("grep -i error", GrepQuery("error", ignore_case=True)),
+        ("-iv 'two words'", GrepQuery("two words", ignore_case=True, invert=True)),
+        ("-E -c 'a|b'", GrepQuery("a|b", extended=True, count=True)),
+        ("-C 2 x", GrepQuery("x", context=2)),
+        ("-C2 x", GrepQuery("x", context=2)),
+        ("-iC3 x", GrepQuery("x", ignore_case=True, context=3)),
+        ("-- -v", GrepQuery("-v")),
+        ('"привет мир"', GrepQuery("привет мир")),
+    ],
+)
+def test_parse(expr: str, expected: GrepQuery) -> None:
+    assert parse_grep(expr) == expected
+
+
+@pytest.mark.parametrize(
+    ("expr", "code"),
+    [
+        ("", GrepErrorCode.EMPTY),
+        ("-i", GrepErrorCode.EMPTY),
+        ("'unclosed", GrepErrorCode.QUOTES),
+        ("-r error", GrepErrorCode.FLAG),
+        ("--include=*.py x", GrepErrorCode.FLAG),
+        ("-C x y", GrepErrorCode.CONTEXT),
+        ("-C 99 y", GrepErrorCode.CONTEXT),
+        ("-C", GrepErrorCode.CONTEXT),
+        ("error /etc/passwd", GrepErrorCode.EXTRA),
+        ("x" * (MAX_PATTERN + 1), GrepErrorCode.TOO_LONG),
+        ("-E '(unclosed'", GrepErrorCode.REGEX),
+    ],
+)
+def test_parse_errors(expr: str, code: GrepErrorCode) -> None:
+    with pytest.raises(GrepError) as e:
+        parse_grep(expr)
+    assert e.value.code is code
+
+
+def test_shell_is_never_involved() -> None:
+    # metacharacters are just pattern text
+    q = parse_grep("'$(rm -rf /); `id`'")
+    assert q.pattern == "$(rm -rf /); `id`"
+    assert to_command(q) == "grep '$(rm -rf /); `id`'"
+
+
+def test_basic_vs_extended_regex() -> None:
+    assert bre_to_ere("a+b") == r"a\+b"
+    assert bre_to_ere(r"a\+b") == "a+b"
+    assert bre_to_ere(r"\(x\|y\)") == "(x|y)"
+    assert bre_to_ere("[+?]x") == "[+?]x"
+    assert bre_to_ere("[]a]+") == r"[]a]\+"
+    assert run(parse_grep("1+1"), "1+1\n11").lines == ["1+1"]
+    assert run(parse_grep("-E 1+1"), "1+1\n11").lines == ["11"]
+
+
+def test_ignore_case_and_invert() -> None:
+    assert run(parse_grep("-i error"), LOG).lines == ["08:02 ERROR connection refused", "08:07 error: timeout"]
+    assert run(parse_grep("-v idle"), LOG).matched == 7
+
+
+def test_count() -> None:
+    result = run(parse_grep("-ci error"), LOG)
+    assert result.matched == 2
+    assert result.lines == []
+
+
+def test_context_merges_and_separates_groups() -> None:
+    result = run(parse_grep("-i -C 1 error"), LOG)
+    assert result.lines == [
+        "08:01 connect db",
+        "08:02 ERROR connection refused",
+        "08:03 retry",
+        "--",
+        "08:06 idle",
+        "08:07 error: timeout",
+        "08:08 done",
+    ]
+    overlapping = run(parse_grep("-C 2 idle"), LOG)
+    assert overlapping.lines == LOG.splitlines()[3:]  # 08:03…08:08, no duplicates, no separator
+
+
+def test_output_is_capped() -> None:
+    text = "\n".join(f"line {i}" for i in range(2000))
+    result = run(parse_grep("line"), text, max_lines=500)
+    assert len(result.lines) == 500
+    assert result.truncated
+    assert result.matched == 2000  # counting goes on
+
+
+@pytest.mark.parametrize("pattern", ["(a+)+$", "(a|aa)+$"])  # regex optimizes the first; the second really blows up
+def test_redos_does_not_hang(pattern: str) -> None:
+    evil = parse_grep(f"-E '{pattern}'")
+    text = "\n".join(["a" * 40 + "!"] * 200 + ["fine"])
+    started = time.monotonic()
+
+    result = run(evil, text, budget=1.0)
+
+    assert time.monotonic() - started < 2.0
+    assert result.matched == 0
+
+
+def test_big_input() -> None:
+    text = "\n".join(f"{i} request ok" if i % 1000 else f"{i} ERROR" for i in range(1, 100_001))
+    result = run(parse_grep("ERROR"), text)
+    assert result.matched == 100
+    assert not result.partial
+
+
+def test_to_command() -> None:
+    assert to_command(parse_grep("-i -C 2 -E 'conn(ect)?'")) == "grep -iE -C 2 'conn(ect)?'"
+    assert to_command(GrepQuery("-x")) == "grep -- -x"
+    assert parse_grep(to_command(parse_grep("-vc 'a b'"))) == parse_grep("-vc 'a b'")
+
+
+def test_catastrophic_lines_are_skipped_then_budget_stops() -> None:
+    text = "\n".join(["a" * 40 + "!"] * 100)
+    result = run(parse_grep("-E '(a|aa)+$'"), text, budget=0.3)
+    assert result.skipped >= 1
+    assert result.partial