2026-10-15 19:30:24 +03:00
11 changed files with 951 additions and 91 deletions
@@ -1,20 +1,37 @@
-"""«📝 Коммит»: browsing the uploads repo tree with buttons (SPEC C-1…C-4). Changes and push — #26, #9."""
+"""«📝 Коммит»: browse the uploads repo tree and collect changes into a draft (SPEC C-1…C-16). Push — #9."""

+import base64
 import html
+import io
 import logging
+from dataclasses import dataclass
 from enum import StrEnum
 from typing import Any

-from aiogram import F, Router
+from aiogram import Bot, F, Router
 from aiogram.enums import ParseMode
 from aiogram.filters.callback_data import CallbackData
 from aiogram.fsm.context import FSMContext
+from aiogram.fsm.state import State, StatesGroup
 from aiogram.types import BufferedInputFile, CallbackQuery, InlineKeyboardMarkup, Message
 from aiogram.utils.keyboard import InlineKeyboardBuilder

 from app.bot.menu import Nav, NavAction
+from app.db.models import ChangeOp, User
+from app.repo.drafts import DraftFull, DraftService, DraftView
 from app.repo.git import Entry, GitError, UploadsRepo
-from app.texts import Texts
+from app.repo.validate import (
+    MAX_FILE_BYTES,
+    ValidationError,
+    check_content,
+    check_name,
+    diff_stat,
+    is_protected,
+    join,
+    python_syntax,
+    strip_fence,
+)
+from app.texts import CommitTexts, Texts

 log = logging.getLogger(__name__)

@@ -32,6 +49,10 @@ class Act(StrEnum):
    DELETE = "d"
    NEW_FILE = "f"
    NEW_DIR = "n"
+    DRAFT = "dr"
+    UNSTAGE = "x"
+    FORCE = "y"
+    FIX = "z"


 class CommitCb(CallbackData, prefix="c"):
@@ -40,6 +61,34 @@ class CommitCb(CallbackData, prefix="c"):
    i: int = 0


+class Flow(StatesGroup):
+    file_name = State()
+    dir_name = State()
+    content = State()
+    syntax = State()
+
+
+class Mark(StrEnum):
+    NONE = ""
+    NEW = "new"
+    MODIFIED = "mod"
+    DELETED = "del"
+
+
+@dataclass(frozen=True)
+class Row:
+    """A line of the directory screen: a repo entry with the draft laid over it."""
+
+    path: str
+    kind: str
+    size: int
+    mark: Mark
+
+    @property
+    def name(self) -> str:
+        return self.path.rsplit("/", 1)[-1]
+
+
 def human_size(n: int) -> str:
    size = float(n)
    for unit in ("Б", "КБ", "МБ"):
@@ -53,26 +102,61 @@ def parent(path: str) -> str:
    return path.rsplit("/", 1)[0] if "/" in path else ""


-def render_dir(texts: Texts, path: str, entries: list[Entry], page: int) -> tuple[str, InlineKeyboardMarkup]:
+def overlay(path: str, entries: list[Entry], draft: DraftView | None, virtual_dirs: list[str]) -> list[Row]:
+    """Repo listing + what the draft adds, changes or deletes in this directory."""
+    changes = {c.path: c for c in draft.changes} if draft else {}
+    rows: dict[str, Row] = {}
+    for e in entries:
+        change = changes.get(e.path)
+        mark, size = Mark.NONE, e.size
+        if change is not None:
+            mark = Mark.DELETED if change.op is ChangeOp.DELETE else Mark.MODIFIED
+            if change.content is not None:
+                size = len(change.content)  # show the size the file will have after the push
+        rows[e.path] = Row(e.path, e.kind, size, mark)
+    prefix = f"{path}/" if path else ""
+    for change in changes.values():
+        if change.op is not ChangeOp.ADD or not change.path.startswith(prefix):
+            continue
+        rest = change.path[len(prefix) :]
+        if "/" in rest:  # a file deeper down: show its top folder here
+            sub = prefix + rest.split("/", 1)[0]
+            rows.setdefault(sub, Row(sub, "dir", 0, Mark.NEW))
+        else:
+            rows[change.path] = Row(change.path, "file", len(change.content or b""), Mark.NEW)
+    for vd in virtual_dirs:
+        if parent(vd) == path:
+            rows.setdefault(vd, Row(vd, "dir", 0, Mark.NEW))
+    return sorted(rows.values(), key=lambda r: (r.kind != "dir", r.name.lower()))
+
+
+def mark_prefix(t: CommitTexts, mark: Mark) -> str:
+    return {Mark.NONE: "", Mark.NEW: t.mark_new, Mark.MODIFIED: t.mark_modified, Mark.DELETED: t.mark_deleted}[mark]
+
+
+def render_dir(
+    texts: Texts, path: str, rows: list[Row], page: int, draft_count: int
+) -> tuple[str, InlineKeyboardMarkup]:
    t = texts.commit
-    pages = max(1, -(-len(entries) // PAGE_SIZE))
+    pages = max(1, -(-len(rows) // PAGE_SIZE))
    page = min(max(page, 0), pages - 1)
    lines = [t.title.format(path=path)]
-    if not entries:
+    if not rows:
        lines.append(t.empty)
    elif pages > 1:
        lines.append(t.page.format(page=page + 1, pages=pages))

    kb = InlineKeyboardBuilder()
    start = page * PAGE_SIZE
-    for index, e in enumerate(entries[start : start + PAGE_SIZE], start=start):
-        label = (
-            t.dir_button.format(name=e.name)
-            if e.kind == "dir"
-            else t.file_button.format(name=e.name, size=human_size(e.size))
+    shown = rows[start : start + PAGE_SIZE]
+    for index, r in enumerate(shown, start=start):
+        base = (
+            t.dir_button.format(name=r.name)
+            if r.kind == "dir"
+            else t.file_button.format(name=r.name, size=human_size(r.size))
        )
-        kb.button(text=label, callback_data=CommitCb(a=Act.OPEN, i=index))
-    sizes = [1] * min(PAGE_SIZE, max(0, len(entries) - start))
+        kb.button(text=mark_prefix(t, r.mark) + base, callback_data=CommitCb(a=Act.OPEN, i=index))
+    sizes = [1] * len(shown)

    paging: list[tuple[str, CommitCb]] = []
    if page > 0:
@@ -87,6 +171,9 @@ def render_dir(texts: Texts, path: str, entries: list[Entry], page: int) -> tupl
    kb.button(text=t.new_file, callback_data=CommitCb(a=Act.NEW_FILE))
    kb.button(text=t.new_dir, callback_data=CommitCb(a=Act.NEW_DIR))
    sizes.append(2)
+    if draft_count:
+        kb.button(text=t.draft_button.format(count=draft_count), callback_data=CommitCb(a=Act.DRAFT))
+        sizes.append(1)
    if path:
        kb.button(text=t.up, callback_data=CommitCb(a=Act.UP))
        sizes.append(1)
@@ -108,80 +195,60 @@ def file_keyboard(texts: Texts) -> InlineKeyboardMarkup:
    return kb.as_markup()


-def build_router(texts: Texts, repo: UploadsRepo) -> Router:
+def to_dir_keyboard(texts: Texts) -> InlineKeyboardMarkup:
+    kb = InlineKeyboardBuilder()
+    kb.button(text=texts.commit.to_dir, callback_data=CommitCb(a=Act.TO_DIR))
+    return kb.as_markup()
+
+
+def build_router(texts: Texts, repo: UploadsRepo, drafts: DraftService) -> Router:
    router = Router(name="commit")
    t = texts.commit

-    async def show_dir(message: Message, state: FSMContext, path: str, page: int, *, edit: bool) -> None:
-        entries = await repo.list_dir(path)
+    async def dir_screen(state: FSMContext, user_id: int, path: str, page: int) -> tuple[str, InlineKeyboardMarkup]:
+        data = await state.get_data()
+        virtual: list[str] = data.get("commit_virtual", [])
+        draft = await drafts.get(user_id)
+        try:
+            entries = await repo.list_dir(path)
+        except GitError:
+            # a folder that exists only in the draft (or a virtual one) has nothing in the repo yet
+            if path not in virtual and not (draft and any(c.path.startswith(f"{path}/") for c in draft.changes)):
+                raise
+            entries = []
+        rows = overlay(path, entries, draft, virtual)
        await state.update_data(
            commit_path=path,
            commit_page=page,
-            commit_entries=[[e.path, e.kind, e.size] for e in entries],
+            commit_rows=[[r.path, r.kind, r.size, r.mark.value] for r in rows],
            commit_file=None,
        )
-        text, kb = render_dir(texts, path, entries, page)
-        if edit:
-            await message.edit_text(text, reply_markup=kb)
+        return render_dir(texts, path, rows, page, len(draft.changes) if draft else 0)
+
+    async def draft_screen(state: FSMContext, user_id: int) -> tuple[str, InlineKeyboardMarkup]:
+        draft = await drafts.get(user_id)
+        changes = draft.changes if draft else []
+        await state.update_data(commit_draft=[c.path for c in changes])
+        kb = InlineKeyboardBuilder()
+        if not changes:
+            text = t.draft_empty
        else:
-            await message.answer(text, reply_markup=kb)
+            ops = {ChangeOp.ADD: t.op_add, ChangeOp.MODIFY: t.op_modify, ChangeOp.DELETE: t.op_delete}
+            lines = [t.draft_title.format(count=len(changes)), ""]
+            lines += [f"{ops[c.op]}  /{c.path}" for c in changes]
+            text = "\n".join(lines)
+            for i, c in enumerate(changes):
+                kb.button(
+                    text=t.unstage.format(name=c.path.rsplit("/", 1)[-1]), callback_data=CommitCb(a=Act.UNSTAGE, i=i)
+                )
+        kb.button(text=t.to_dir, callback_data=CommitCb(a=Act.TO_DIR))
+        kb.adjust(1)
+        return text, kb.as_markup()

-    @router.message(F.text == texts.menu.commit)
-    async def open_commit(message: Message, state: FSMContext) -> None:
-        await state.clear()
-        try:
-            await repo.refresh()
-            await show_dir(message, state, "", 0, edit=False)
-        except GitError:
-            log.exception("uploads repo unavailable")
-            await message.answer(t.unavailable)
-
-    @router.callback_query(CommitCb.filter())
-    async def on_action(query: CallbackQuery, callback_data: CommitCb, state: FSMContext) -> None:
-        if not isinstance(query.message, Message):
-            await query.answer()
-            return
-        msg = query.message
-        data: dict[str, Any] = await state.get_data()
-        path: str = data.get("commit_path", "")
-        entries: list[list[Any]] = data.get("commit_entries", [])
-        try:
-            match callback_data.a:
-                case Act.OPEN:
-                    if not 0 <= callback_data.i < len(entries):
-                        await query.answer()  # stale button from an older screen
-                        return
-                    target, kind, size = entries[callback_data.i]
-                    if kind == "dir":
-                        await repo.refresh()
-                        await show_dir(msg, state, target, 0, edit=True)
-                    else:
-                        await state.update_data(commit_file=target)
-                        await msg.edit_text(await file_card(target, size), reply_markup=file_keyboard(texts))
-                case Act.UP:
-                    await show_dir(msg, state, parent(path), 0, edit=True)
-                case Act.PAGE:
-                    await state.update_data(commit_page=callback_data.i)
-                    real = [Entry(p, k, s) for p, k, s in entries]
-                    text, kb = render_dir(texts, path, real, callback_data.i)
-                    await msg.edit_text(text, reply_markup=kb)
-                case Act.TO_DIR:
-                    await show_dir(msg, state, path, data.get("commit_page", 0), edit=True)
-                case Act.VIEW:
-                    file_path = data.get("commit_file")
-                    if file_path:
-                        await send_file(msg, file_path)
-                case Act.REPLACE | Act.DELETE | Act.NEW_FILE | Act.NEW_DIR:
-                    await query.answer(t.soon, show_alert=True)
-                    return
-        except GitError:
-            log.exception("uploads repo unavailable")
-            await query.answer(t.unavailable, show_alert=True)
-            return
-        await query.answer()
-
-    async def file_card(path: str, size: int) -> str:
+    async def file_card(user_id: int, path: str, size: int, mark: Mark) -> str:
        card = t.file_card.format(path=path, size=human_size(size))
+        if mark is Mark.NEW:
+            return f"{card}\n{t.in_draft_new}"
        info = await repo.last_commit(path)
        tail = (
            t.last_commit.format(
@@ -190,11 +257,21 @@ def build_router(texts: Texts, repo: UploadsRepo) -> Router:
            if info
            else t.no_commits
        )
-        return f"{card}\n{tail}"
+        note = {Mark.MODIFIED: f"\n{t.in_draft_modified}", Mark.DELETED: f"\n{t.in_draft_deleted}"}.get(mark, "")
+        return f"{card}\n{tail}{note}"

-    async def send_file(msg: Message, path: str) -> None:
-        content = await repo.read(path)
-        name = path.rsplit("/", 1)[-1]
+    async def current_content(user_id: int, path: str) -> bytes | None:
+        """What the member sees as the file now: the draft version if there is one."""
+        draft = await drafts.get(user_id)
+        change = draft.change_for(path) if draft else None
+        if change is not None:
+            return change.content  # None for a deleted file
+        return await repo.read(path)
+
+    async def send_file(msg: Message, user_id: int, path: str) -> None:
+        content = await current_content(user_id, path)
+        if content is None:
+            return
        try:
            text = content.decode("utf-8")
        except UnicodeDecodeError:
@@ -202,6 +279,224 @@ def build_router(texts: Texts, repo: UploadsRepo) -> Router:
        if text is not None and "\0" not in text and len(text) <= INLINE_VIEW_LIMIT:
            await msg.answer(f"<b>/{html.escape(path)}</b>\n<pre>{html.escape(text)}</pre>", parse_mode=ParseMode.HTML)
        else:
-            await msg.answer_document(BufferedInputFile(content, name), caption=t.sent_as_file)
+            await msg.answer_document(BufferedInputFile(content, path.rsplit("/", 1)[-1]), caption=t.sent_as_file)
+
+    async def stage(message: Message, state: FSMContext, member: User, path: str, op: ChangeOp, content: bytes) -> None:
+        old = await current_content(member.tg_id, path) if op is ChangeOp.MODIFY else None
+        try:
+            await drafts.put(member.tg_id, await repo.head(), path, op, content)
+        except DraftFull:
+            await message.answer(t.draft_full)
+            return
+        if op is ChangeOp.ADD:
+            note = t.added.format(path=path)
+        else:
+            added, removed = diff_stat((old or b"").decode("utf-8", errors="replace"), content.decode("utf-8"))
+            note = t.modified.format(path=path, added=added, removed=removed)
+        data = await state.get_data()
+        # a virtual folder becomes real as soon as a file lands in it
+        virtual = [v for v in data.get("commit_virtual", []) if not path.startswith(f"{v}/")]
+        await state.set_state(None)
+        await state.update_data(commit_virtual=virtual, commit_pending=None)
+        text, kb = await dir_screen(state, member.tg_id, data.get("commit_path", ""), 0)
+        await message.answer(f"{note}\n\n{text}", reply_markup=kb)
+
+    # ---- entry point -------------------------------------------------------------------------------------------
+
+    @router.message(F.text == texts.menu.commit)
+    async def open_commit(message: Message, state: FSMContext, member: User) -> None:
+        await state.clear()
+        try:
+            await repo.refresh()
+            text, kb = await dir_screen(state, member.tg_id, "", 0)
+        except GitError:
+            log.exception("uploads repo unavailable")
+            await message.answer(t.unavailable)
+            return
+        await message.answer(text, reply_markup=kb)
+
+    # ---- buttons -----------------------------------------------------------------------------------------------
+
+    @router.callback_query(CommitCb.filter())
+    async def on_action(query: CallbackQuery, callback_data: CommitCb, state: FSMContext, member: User) -> None:
+        if not isinstance(query.message, Message):
+            await query.answer()
+            return
+        msg = query.message
+        data: dict[str, Any] = await state.get_data()
+        path: str = data.get("commit_path", "")
+        rows: list[list[Any]] = data.get("commit_rows", [])
+        uid = member.tg_id
+        try:
+            match callback_data.a:
+                case Act.OPEN:
+                    if not 0 <= callback_data.i < len(rows):
+                        await query.answer()  # stale button from an older screen
+                        return
+                    target, kind, size, mark = rows[callback_data.i]
+                    if kind == "dir":
+                        await repo.refresh()
+                        text, kb = await dir_screen(state, uid, target, 0)
+                        await msg.edit_text(text, reply_markup=kb)
+                    else:
+                        await state.update_data(commit_file=target)
+                        await msg.edit_text(
+                            await file_card(uid, target, size, Mark(mark)), reply_markup=file_keyboard(texts)
+                        )
+                case Act.UP:
+                    text, kb = await dir_screen(state, uid, parent(path), 0)
+                    await msg.edit_text(text, reply_markup=kb)
+                case Act.PAGE:
+                    real = [Row(p, k, s, Mark(m)) for p, k, s, m in rows]
+                    draft = await drafts.get(uid)
+                    await state.update_data(commit_page=callback_data.i)
+                    text, kb = render_dir(texts, path, real, callback_data.i, len(draft.changes) if draft else 0)
+                    await msg.edit_text(text, reply_markup=kb)
+                case Act.TO_DIR:
+                    await state.set_state(None)
+                    text, kb = await dir_screen(state, uid, path, data.get("commit_page", 0))
+                    await msg.edit_text(text, reply_markup=kb)
+                case Act.VIEW:
+                    if data.get("commit_file"):
+                        await send_file(msg, uid, data["commit_file"])
+                case Act.NEW_FILE:
+                    await state.set_state(Flow.file_name)
+                    await msg.edit_text(t.ask_file_name.format(dir=path), reply_markup=to_dir_keyboard(texts))
+                case Act.NEW_DIR:
+                    await state.set_state(Flow.dir_name)
+                    await msg.edit_text(t.ask_dir_name.format(dir=path), reply_markup=to_dir_keyboard(texts))
+                case Act.REPLACE:
+                    target = data.get("commit_file")
+                    if not target:
+                        await query.answer()
+                        return
+                    if is_protected(target):
+                        await query.answer(t.protected, show_alert=True)
+                        return
+                    await state.set_state(Flow.content)
+                    await state.update_data(commit_target=target, commit_op=ChangeOp.MODIFY.value)
+                    await msg.edit_text(t.ask_content.format(path=target), reply_markup=to_dir_keyboard(texts))
+                case Act.DELETE:
+                    target = data.get("commit_file")
+                    if not target:
+                        await query.answer()
+                        return
+                    if is_protected(target):
+                        await query.answer(t.protected, show_alert=True)
+                        return
+                    await drafts.put(uid, await repo.head(), target, ChangeOp.DELETE, None)
+                    text, kb = await dir_screen(state, uid, path, data.get("commit_page", 0))
+                    await msg.edit_text(f"{t.deleted.format(path=target)}\n\n{text}", reply_markup=kb)
+                case Act.DRAFT:
+                    text, kb = await draft_screen(state, uid)
+                    await msg.edit_text(text, reply_markup=kb)
+                case Act.UNSTAGE:
+                    paths: list[str] = data.get("commit_draft", [])
+                    if 0 <= callback_data.i < len(paths):
+                        await drafts.drop(uid, paths[callback_data.i])
+                    text, kb = await draft_screen(state, uid)
+                    await msg.edit_text(text, reply_markup=kb)
+                case Act.FORCE:
+                    pending = data.get("commit_pending")
+                    if pending is None or await state.get_state() != Flow.syntax.state:
+                        await query.answer()
+                        return
+                    await query.answer()
+                    await stage(
+                        msg,
+                        state,
+                        member,
+                        data["commit_target"],
+                        ChangeOp(data["commit_op"]),
+                        base64.b64decode(pending),
+                    )
+                    return
+                case Act.FIX:
+                    await state.set_state(Flow.content)
+                    await state.update_data(commit_pending=None)
+                    await msg.edit_text(
+                        t.ask_content.format(path=data.get("commit_target", "")), reply_markup=to_dir_keyboard(texts)
+                    )
+        except GitError:
+            log.exception("uploads repo unavailable")
+            await query.answer(t.unavailable, show_alert=True)
+            return
+        except DraftFull:
+            await query.answer(t.draft_full, show_alert=True)
+            return
+        await query.answer()
+
+    # ---- text input --------------------------------------------------------------------------------------------
+
+    @router.message(Flow.file_name, F.text)
+    async def got_file_name(message: Message, state: FSMContext, member: User) -> None:
+        data = await state.get_data()
+        directory = data.get("commit_path", "")
+        try:
+            name = check_name(message.text or "")
+        except ValidationError:
+            await message.answer(t.bad_name)
+            return
+        path = join(directory, name)
+        if is_protected(path):
+            await message.answer(t.protected)
+            return
+        taken = {row[0] for row in data.get("commit_rows", [])}
+        if path in taken:
+            await message.answer(t.exists)
+            return
+        await state.set_state(Flow.content)
+        await state.update_data(commit_target=path, commit_op=ChangeOp.ADD.value)
+        await message.answer(t.ask_content.format(path=path), reply_markup=to_dir_keyboard(texts))
+
+    @router.message(Flow.dir_name, F.text)
+    async def got_dir_name(message: Message, state: FSMContext, member: User) -> None:
+        data = await state.get_data()
+        directory = data.get("commit_path", "")
+        try:
+            name = check_name(message.text or "")
+        except ValidationError:
+            await message.answer(t.bad_name)
+            return
+        path = join(directory, name)
+        if is_protected(path + "/x"):
+            await message.answer(t.protected)
+            return
+        if path in {row[0] for row in data.get("commit_rows", [])}:
+            await message.answer(t.exists)
+            return
+        await state.set_state(None)
+        await state.update_data(commit_virtual=[*data.get("commit_virtual", []), path])
+        text, kb = await dir_screen(state, member.tg_id, path, 0)
+        await message.answer(text, reply_markup=kb)
+
+    @router.message(Flow.content, F.text | F.document)
+    async def got_content(message: Message, state: FSMContext, member: User, bot: Bot) -> None:
+        data = await state.get_data()
+        target: str = data["commit_target"]
+        if message.document is not None:
+            if (message.document.file_size or 0) > MAX_FILE_BYTES:
+                await message.answer(t.too_big)
+                return
+            buf = io.BytesIO()
+            await bot.download(message.document, destination=buf)
+            raw = buf.getvalue()
+        else:
+            raw = strip_fence(message.text or "").encode("utf-8")
+        try:
+            text = check_content(raw)
+        except ValidationError as e:
+            await message.answer({"too_big": t.too_big, "binary": t.binary, "encoding": t.encoding}[str(e)])
+            return
+        issue = python_syntax(target, text)
+        if issue is not None:
+            await state.set_state(Flow.syntax)
+            await state.update_data(commit_pending=base64.b64encode(raw).decode())
+            kb = InlineKeyboardBuilder()
+            kb.button(text=t.fix, callback_data=CommitCb(a=Act.FIX))
+            kb.button(text=t.force, callback_data=CommitCb(a=Act.FORCE))
+            await message.answer(t.syntax.format(line=issue.line, message=issue.message), reply_markup=kb.as_markup())
+            return
+        await stage(message, state, member, target, ChangeOp(data["commit_op"]), raw)

    return router
@@ -17,6 +17,7 @@ from app.db.migrate import upgrade
 from app.db.session import SessionMaker, make_engine, make_sessionmaker
 from app.health import heartbeat
 from app.logs_setup import setup_logging
+from app.repo.drafts import DraftService
 from app.repo.git import UploadsRepo
 from app.texts import Texts, load_texts

@@ -30,7 +31,7 @@ def build_dispatcher(texts: Texts, sessions: SessionMaker, access: AccessService
    dp.message.outer_middleware(gate)
    dp.callback_query.outer_middleware(gate)
    dp.include_router(members.build_router(texts, access))
-    dp.include_router(commit.build_router(texts, repo))
+    dp.include_router(commit.build_router(texts, repo, DraftService(sessions)))
    dp.include_router(common.build_router(texts, access))
    return dp

@@ -0,0 +1,107 @@
+"""A member's draft: pending add/modify/delete changes until Push (SPEC C-14, C-15). One draft per member."""
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from datetime import UTC, datetime, timedelta
+
+from sqlalchemy import delete, select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from app.db.models import ChangeOp, Draft, DraftChange, utcnow
+from app.db.session import SessionMaker
+
+MAX_CHANGES = 50
+
+
+class DraftFull(Exception):
+    pass
+
+
+@dataclass(frozen=True)
+class Change:
+    path: str
+    op: ChangeOp
+    content: bytes | None
+
+
+@dataclass(frozen=True)
+class DraftView:
+    base_sha: str
+    message: str | None
+    changes: list[Change]
+
+    def change_for(self, path: str) -> Change | None:
+        return next((c for c in self.changes if c.path == path), None)
+
+
+class DraftService:
+    def __init__(
+        self, sessions: SessionMaker, ttl: timedelta = timedelta(hours=24), clock: Callable[[], datetime] = utcnow
+    ):
+        self._sessions = sessions
+        self._ttl = ttl
+        self._clock = clock
+
+    async def get(self, user_id: int) -> DraftView | None:
+        async with self._sessions() as s:
+            draft = await self._load(s, user_id)
+            if draft is None:
+                return None
+            return DraftView(
+                base_sha=draft.base_sha,
+                message=draft.message,
+                changes=[Change(c.path, c.op, c.content) for c in draft.changes],
+            )
+
+    async def put(self, user_id: int, base_sha: str, path: str, op: ChangeOp, content: bytes | None) -> None:
+        """Record a change. Deleting a file that only exists in the draft just drops it from the draft."""
+        async with self._sessions.begin() as s:
+            draft = await self._load(s, user_id)
+            if draft is None:
+                draft = Draft(
+                    user_id=user_id, base_sha=base_sha, created_at=self._clock(), expires_at=self._clock() + self._ttl
+                )
+                s.add(draft)
+            existing = next((c for c in draft.changes if c.path == path), None)
+            if existing is not None:
+                if op is ChangeOp.DELETE and existing.op is ChangeOp.ADD:
+                    draft.changes.remove(existing)
+                    return
+                # editing a file added in this draft keeps it an "add"
+                existing.op = ChangeOp.ADD if existing.op is ChangeOp.ADD and op is ChangeOp.MODIFY else op
+                existing.content = content
+            else:
+                if len(draft.changes) >= MAX_CHANGES:
+                    raise DraftFull
+                draft.changes.append(DraftChange(path=path, op=op, content=content))
+            draft.expires_at = self._clock() + self._ttl
+
+    async def drop(self, user_id: int, path: str) -> None:
+        async with self._sessions.begin() as s:
+            draft = await self._load(s, user_id)
+            if draft is None:
+                return
+            draft.changes = [c for c in draft.changes if c.path != path]
+
+    async def set_message(self, user_id: int, message: str) -> None:
+        async with self._sessions.begin() as s:
+            draft = await self._load(s, user_id)
+            if draft is not None:
+                draft.message = message
+
+    async def clear(self, user_id: int) -> None:
+        async with self._sessions.begin() as s:
+            await s.execute(delete(Draft).where(Draft.user_id == user_id))
+
+    async def _load(self, s: AsyncSession, user_id: int) -> Draft | None:
+        draft = await s.scalar(select(Draft).where(Draft.user_id == user_id).options(selectinload(Draft.changes)))
+        if draft is not None and _aware(draft.expires_at) <= self._clock():
+            await s.delete(draft)
+            await s.flush()
+            return None
+        return draft
+
+
+def _aware(value: datetime) -> datetime:
+    return value if value.tzinfo is not None else value.replace(tzinfo=UTC)
@@ -0,0 +1,76 @@
+"""Checks for names and file contents before anything goes into a draft (SPEC C-10, C-12, C-16). No code runs here."""
+
+import ast
+import difflib
+import re
+from dataclasses import dataclass
+
+MAX_FILE_BYTES = 100 * 1024
+NAME = re.compile(r"^[A-Za-z0-9._-]{1,100}$")
+# Bot users can't touch the CI of the uploads repo or its helper scripts (SPEC C-16, ADR-014)
+PROTECTED_PREFIXES = (".sourcecraft/", ".tgit/", ".git/")
+PROTECTED_FILES = {"ruff.toml"}
+_FENCE = re.compile(r"^\s*```[\w+-]*[ \t]*\n(.*?)\n?```\s*$", re.DOTALL)
+
+
+class ValidationError(ValueError):
+    pass
+
+
+@dataclass(frozen=True)
+class SyntaxIssue:
+    line: int
+    message: str
+
+
+def check_name(name: str) -> str:
+    name = name.strip()
+    if not NAME.match(name) or name in {".", ".."}:
+        raise ValidationError("name")
+    return name
+
+
+def is_protected(path: str) -> bool:
+    return path in PROTECTED_FILES or any(path.startswith(p) or path + "/" == p for p in PROTECTED_PREFIXES)
+
+
+def join(directory: str, name: str) -> str:
+    return f"{directory}/{name}" if directory else name
+
+
+def strip_fence(text: str) -> str:
+    """Code pasted as a Telegram message often comes wrapped in ``` — keep only what's inside."""
+    match = _FENCE.match(text)
+    return match.group(1) if match else text
+
+
+def check_content(data: bytes) -> str:
+    """Size, encoding, NUL bytes. Returns the decoded text."""
+    if len(data) > MAX_FILE_BYTES:
+        raise ValidationError("too_big")
+    if b"\0" in data:
+        raise ValidationError("binary")
+    try:
+        return data.decode("utf-8")
+    except UnicodeDecodeError:
+        raise ValidationError("encoding") from None
+
+
+def python_syntax(path: str, text: str) -> SyntaxIssue | None:
+    if not path.endswith(".py"):
+        return None
+    try:
+        ast.parse(text, filename=path)
+    except SyntaxError as e:
+        return SyntaxIssue(line=e.lineno or 0, message=e.msg)
+    return None
+
+
+def diff_stat(old: str, new: str) -> tuple[int, int]:
+    added = removed = 0
+    for line in difflib.ndiff(old.splitlines(), new.splitlines()):
+        if line.startswith("+ "):
+            added += 1
+        elif line.startswith("- "):
+            removed += 1
+    return added, removed
@@ -75,6 +75,35 @@ class CommitTexts(_Strict):
    soon: str
    unavailable: str
    sent_as_file: str
+    ask_file_name: str
+    ask_dir_name: str
+    bad_name: str
+    exists: str
+    protected: str
+    ask_content: str
+    too_big: str
+    binary: str
+    encoding: str
+    syntax: str
+    fix: str
+    force: str
+    added: str
+    modified: str
+    deleted: str
+    draft_button: str
+    draft_title: str
+    draft_empty: str
+    unstage: str
+    draft_full: str
+    in_draft_new: str
+    in_draft_modified: str
+    in_draft_deleted: str
+    mark_new: str
+    mark_modified: str
+    mark_deleted: str
+    op_add: str
+    op_modify: str
+    op_delete: str


 class Texts(_Strict):
@@ -78,3 +78,32 @@ commit:
  soon: "Будет в следующей версии."
  unavailable: "Репозиторий загрузок недоступен, попробуйте через минуту."
  sent_as_file: "Файл большой или бинарный — отправил документом."
+  ask_file_name: "Имя нового файла в /{dir} (латиница, цифры, «.», «_», «-»):"
+  ask_dir_name: "Имя новой папки в /{dir}:"
+  bad_name: "Недопустимое имя: латиница, цифры, «.», «_», «-», до 100 символов. Пришлите другое."
+  exists: "Такое имя уже есть в этой папке. Пришлите другое."
+  protected: "Это служебный путь репозитория — из бота его менять нельзя."
+  ask_content: "Пришлите содержимое /{path} — текстом сообщения или файлом (до 100 КБ)."
+  too_big: "Больше 100 КБ — не принимаю."
+  binary: "Похоже на бинарный файл — принимаю только текст."
+  encoding: "Файл не в кодировке UTF-8."
+  syntax: "⚠️ Синтаксическая ошибка, строка {line}: {message}"
+  fix: "✏️ Исправить"
+  force: "Всё равно добавить"
+  added: "🆕 /{path} — добавлен в черновик."
+  modified: "✏️ /{path} — в черновике: +{added} −{removed}."
+  deleted: "🗑 /{path} — в черновике на удаление."
+  draft_button: "🧾 Черновик · {count}"
+  draft_title: "🧾 Черновик · изменений: {count}"
+  draft_empty: "Черновик пуст."
+  unstage: "↩️ убрать {name}"
+  draft_full: "В черновике уже 50 изменений — запушьте или уберите лишнее."
+  in_draft_new: "В черновике: новый файл."
+  in_draft_modified: "В черновике: изменён."
+  in_draft_deleted: "В черновике: удалён."
+  mark_new: "🆕 "
+  mark_modified: "✏️ "
+  mark_deleted: "🗑 "
+  op_add: "A"
+  op_modify: "M"
+  op_delete: "D"
@@ -87,13 +87,11 @@ async def test_pagination(tg: TgClient, texts: Texts) -> None:
    assert labels(second.reply_markup)[0].startswith("📄 f20.txt") and texts.commit.prev in labels(second.reply_markup)


-async def test_unfinished_actions_and_stale_buttons(tg: TgClient, texts: Texts) -> None:
+async def test_stale_button_is_ignored(tg: TgClient, texts: Texts) -> None:
    await tg.send(ADMIN, texts.menu.commit)
-    await tg.press(ADMIN, cb(Act.NEW_FILE))
    await tg.press(ADMIN, cb(Act.OPEN, 99))

-    soon, stale = tg.session.sent(AnswerCallbackQuery)
-    assert soon.text == texts.commit.soon and soon.show_alert
+    [stale] = tg.session.sent(AnswerCallbackQuery)
    assert stale.text is None
    assert tg.session.sent(EditMessageText) == []

@@ -0,0 +1,162 @@
+import pytest
+from aiogram.methods import AnswerCallbackQuery, EditMessageText, SendMessage
+from aiogram.types import InlineKeyboardMarkup
+
+from app.access.service import AccessService
+from app.bot.routers.commit import Act, CommitCb
+from app.db.session import SessionMaker
+from app.main import build_dispatcher
+from app.repo.git import UploadsRepo
+from app.texts import Texts
+from tests.conftest import ADMIN
+from tests.fakes import TgClient
+
+
+@pytest.fixture
+def tg(texts: Texts, sessions: SessionMaker, access: AccessService, repo: UploadsRepo) -> TgClient:
+    return TgClient(build_dispatcher(texts, sessions, access, repo))
+
+
+def cb(action: Act, i: int = 0) -> str:
+    return CommitCb(a=action, i=i).pack()
+
+
+def labels(markup: object) -> list[str]:
+    assert isinstance(markup, InlineKeyboardMarkup)
+    return [b.text for row in markup.inline_keyboard for b in row]
+
+
+def last_text(tg: TgClient) -> SendMessage:
+    return tg.session.sent(SendMessage)[-1]
+
+
+async def to_hello(tg: TgClient, texts: Texts) -> None:
+    await tg.send(ADMIN, texts.menu.commit)
+    await tg.press(ADMIN, cb(Act.OPEN, 2))  # services
+    await tg.press(ADMIN, cb(Act.OPEN, 0))  # services/hello
+
+
+async def test_new_file_from_fenced_text(tg: TgClient, texts: Texts) -> None:
+    await to_hello(tg, texts)
+    await tg.press(ADMIN, cb(Act.NEW_FILE))
+    await tg.send(ADMIN, "utils.py")
+    await tg.send(ADMIN, "```python\ndef add(a, b):\n    return a + b\n```")
+
+    reply = last_text(tg)
+    assert reply.text.startswith(texts.commit.added.format(path="services/hello/utils.py"))
+    got = labels(reply.reply_markup)
+    assert "🆕 📄 utils.py · 31 Б" in got  # fence stripped, no trailing newline
+    assert texts.commit.draft_button.format(count=1) in got
+
+    await tg.press(ADMIN, cb(Act.OPEN, 1))  # utils.py (main.py is 0)
+    await tg.press(ADMIN, cb(Act.VIEW))
+    view = last_text(tg)
+    assert "def add(a, b):" in view.text and "```" not in view.text
+
+
+async def test_replace_with_document_shows_diff(tg: TgClient, texts: Texts) -> None:
+    await to_hello(tg, texts)
+    await tg.press(ADMIN, cb(Act.OPEN, 0))  # main.py
+    await tg.press(ADMIN, cb(Act.REPLACE))
+    await tg.send_document(ADMIN, "main.py", b"print('hello')\nprint('bye')\n")
+
+    reply = last_text(tg)
+    assert reply.text.startswith(texts.commit.modified.format(path="services/hello/main.py", added=1, removed=0))
+    assert "✏️ 📄 main.py · 28 Б" in labels(reply.reply_markup)
+
+
+async def test_delete_marks_and_draft_lists(tg: TgClient, texts: Texts) -> None:
+    await tg.send(ADMIN, texts.menu.commit)
+    await tg.press(ADMIN, cb(Act.OPEN, 3))  # README.md
+    await tg.press(ADMIN, cb(Act.DELETE))
+    deleted = tg.session.sent(EditMessageText)[-1]
+    assert deleted.text.startswith(texts.commit.deleted.format(path="README.md"))
+    assert "🗑 📄 README.md · 10 Б" in labels(deleted.reply_markup)
+
+    await tg.press(ADMIN, cb(Act.DRAFT))
+    draft = tg.session.sent(EditMessageText)[-1]
+    assert "D  /README.md" in draft.text
+
+    await tg.press(ADMIN, cb(Act.UNSTAGE, 0))
+    assert tg.session.sent(EditMessageText)[-1].text == texts.commit.draft_empty
+
+
+async def test_syntax_error_force_or_fix(tg: TgClient, texts: Texts) -> None:
+    await to_hello(tg, texts)
+    await tg.press(ADMIN, cb(Act.NEW_FILE))
+    await tg.send(ADMIN, "bad.py")
+    await tg.send(ADMIN, "def f(:\n    pass")
+
+    warn = last_text(tg)
+    assert warn.text.startswith("⚠️") and "1" in warn.text
+    assert labels(warn.reply_markup) == [texts.commit.fix, texts.commit.force]
+
+    await tg.press(ADMIN, cb(Act.FIX))
+    assert tg.session.sent(EditMessageText)[-1].text == texts.commit.ask_content.format(path="services/hello/bad.py")
+    await tg.send(ADMIN, "def f(:\n    pass")
+    await tg.press(ADMIN, cb(Act.FORCE))
+    assert last_text(tg).text.startswith(texts.commit.added.format(path="services/hello/bad.py"))
+
+
+async def test_virtual_folder_becomes_real_with_a_file(tg: TgClient, texts: Texts) -> None:
+    await tg.send(ADMIN, texts.menu.commit)
+    await tg.press(ADMIN, cb(Act.OPEN, 2))  # services
+    await tg.press(ADMIN, cb(Act.NEW_DIR))
+    await tg.send(ADMIN, "api")
+    inside = last_text(tg)
+    assert inside.text == f"{texts.commit.title.format(path='services/api')}\n{texts.commit.empty}"
+
+    await tg.press(ADMIN, cb(Act.NEW_FILE))
+    await tg.send(ADMIN, "main.py")
+    await tg.send(ADMIN, "print('api')")
+    await tg.press(ADMIN, cb(Act.UP))
+
+    services = tg.session.sent(EditMessageText)[-1]
+    assert "🆕 📁 api" in labels(services.reply_markup)
+
+
+async def test_names_rejected(tg: TgClient, texts: Texts) -> None:
+    await tg.send(ADMIN, texts.menu.commit)
+    await tg.press(ADMIN, cb(Act.NEW_FILE))
+    for bad in ["../etc", "README.md", "ruff.toml"]:
+        await tg.send(ADMIN, bad)
+
+    assert [m.text for m in tg.session.sent(SendMessage)][-3:] == [
+        texts.commit.bad_name,
+        texts.commit.exists,
+        texts.commit.protected,
+    ]
+
+
+async def test_binary_document_rejected(tg: TgClient, texts: Texts) -> None:
+    await to_hello(tg, texts)
+    await tg.press(ADMIN, cb(Act.NEW_FILE))
+    await tg.send(ADMIN, "img.png")
+    await tg.send_document(ADMIN, "img.png", b"\x89PNG\x00\x00")
+
+    assert last_text(tg).text == texts.commit.binary
+
+
+async def test_draft_survives_a_restart(
+    texts: Texts, sessions: SessionMaker, access: AccessService, repo: UploadsRepo
+) -> None:
+    first = TgClient(build_dispatcher(texts, sessions, access, repo))
+    await first.send(ADMIN, texts.menu.commit)
+    await first.press(ADMIN, cb(Act.OPEN, 3))
+    await first.press(ADMIN, cb(Act.DELETE))
+
+    second = TgClient(build_dispatcher(texts, sessions, access, repo))  # same DB, new bot process
+    await second.send(ADMIN, texts.menu.commit)
+    assert texts.commit.draft_button.format(count=1) in labels(second.session.sent(SendMessage)[-1].reply_markup)
+
+
+async def test_protected_file_cannot_be_replaced(tg: TgClient, texts: Texts, repo: UploadsRepo) -> None:
+    await tg.send(ADMIN, texts.menu.commit)
+    # fake a card for a protected path via FSM: open README then rewrite the selection
+    await tg.press(ADMIN, cb(Act.OPEN, 3))
+    state = tg.dp.fsm.get_context(tg.bot, chat_id=ADMIN, user_id=ADMIN)
+    await state.update_data(commit_file=".sourcecraft/ci.yaml")
+    await tg.press(ADMIN, cb(Act.REPLACE))
+
+    answer = tg.session.sent(AnswerCallbackQuery)[-1]
+    assert answer.text == texts.commit.protected and answer.show_alert
@@ -7,9 +7,9 @@ from typing import Any

 from aiogram import Bot, Dispatcher
 from aiogram.client.session.base import BaseSession
-from aiogram.methods import EditMessageText, GetMe, SendMessage, SendPhoto, TelegramMethod
+from aiogram.methods import EditMessageText, GetFile, GetMe, SendMessage, SendPhoto, TelegramMethod
 from aiogram.methods.base import TelegramType
-from aiogram.types import Chat, Message, Update, User
+from aiogram.types import Chat, File, Message, Update, User

 BOT_TOKEN = "42:TEST-TOKEN"

@@ -19,6 +19,7 @@ class FakeSession(BaseSession):
        super().__init__()
        self.requests: list[TelegramMethod[Any]] = []
        self._ids = count(1000)
+        self.files: dict[str, bytes] = {}  # file_id -> content, for documents users "upload"

    async def make_request(
        self,
@@ -27,6 +28,10 @@ class FakeSession(BaseSession):
        timeout: int | None = None,  # noqa: ASYNC109 - signature fixed by aiogram BaseSession
    ) -> TelegramType:
        self.requests.append(method)
+        if isinstance(method, GetFile):
+            return File(  # type: ignore[return-value]
+                file_id=method.file_id, file_unique_id=method.file_id, file_path=f"documents/{method.file_id}"
+            )
        if isinstance(method, GetMe):
            return User(id=42, is_bot=True, first_name="tgit", username="tgit_test_bot")  # type: ignore[return-value]
        if isinstance(method, SendPhoto):
@@ -54,9 +59,9 @@ class FakeSession(BaseSession):
        timeout: int = 30,  # noqa: ASYNC109 - signature fixed by aiogram BaseSession
        chunk_size: int = 65536,
        raise_for_status: bool = True,
-    ) -> AsyncGenerator[bytes, None]:  # pragma: no cover - not used
-        raise NotImplementedError
-        yield b""
+    ) -> AsyncGenerator[bytes, None]:
+        file_id = url.rsplit("/", 1)[-1]
+        yield self.files[file_id]

    async def close(self) -> None:
        pass
@@ -92,6 +97,18 @@ class TgClient:
            message["entities"] = [{"type": "bot_command", "offset": 0, "length": len(cmd)}]
        await self._feed({"message": message})

+    async def send_document(self, tg_id: int, name: str, content: bytes) -> None:
+        file_id = f"doc{next(self._message_ids)}"
+        self.session.files[file_id] = content
+        message = {
+            "message_id": next(self._message_ids),
+            "date": int(datetime.now(UTC).timestamp()),
+            "chat": {"id": tg_id, "type": "private"},
+            "from": self.user(tg_id),
+            "document": {"file_id": file_id, "file_unique_id": file_id, "file_name": name, "file_size": len(content)},
+        }
+        await self._feed({"message": message})
+
    async def press(self, tg_id: int, data: str, message_text: str = "section") -> None:
        callback = {
            "id": str(next(self._update_ids)),
@@ -0,0 +1,72 @@
+from datetime import UTC, datetime, timedelta
+
+import pytest
+
+from app.db.models import ChangeOp, User
+from app.db.session import SessionMaker
+from app.repo.drafts import MAX_CHANGES, DraftFull, DraftService
+
+UID = 7
+SHA = "a" * 40
+
+
+class Clock:
+    now = datetime(2026, 10, 15, tzinfo=UTC)
+
+    def __call__(self) -> datetime:
+        return self.now
+
+
+@pytest.fixture
+async def svc(sessions: SessionMaker) -> DraftService:
+    async with sessions.begin() as s:
+        s.add(User(tg_id=UID, full_name="u"))
+    return DraftService(sessions, clock=Clock())
+
+
+async def test_put_get_and_order(svc: DraftService) -> None:
+    await svc.put(UID, SHA, "b.py", ChangeOp.ADD, b"b")
+    await svc.put(UID, "other-sha", "a.py", ChangeOp.MODIFY, b"a")
+
+    draft = await svc.get(UID)
+    assert draft is not None and draft.base_sha == SHA  # base fixed when the draft started
+    assert [(c.path, c.op) for c in draft.changes] == [("b.py", ChangeOp.ADD), ("a.py", ChangeOp.MODIFY)]
+
+
+async def test_editing_a_new_file_keeps_it_added_and_deleting_it_drops_it(svc: DraftService) -> None:
+    await svc.put(UID, SHA, "n.py", ChangeOp.ADD, b"1")
+    await svc.put(UID, SHA, "n.py", ChangeOp.MODIFY, b"2")
+    draft = await svc.get(UID)
+    assert draft is not None and draft.changes[0].op is ChangeOp.ADD and draft.changes[0].content == b"2"
+
+    await svc.put(UID, SHA, "n.py", ChangeOp.DELETE, None)
+    draft = await svc.get(UID)
+    assert draft is not None and draft.changes == []
+
+
+async def test_drop_message_clear(svc: DraftService) -> None:
+    await svc.put(UID, SHA, "a.py", ChangeOp.ADD, b"1")
+    await svc.put(UID, SHA, "b.py", ChangeOp.DELETE, None)
+    await svc.drop(UID, "a.py")
+    await svc.set_message(UID, "feat: x")
+
+    draft = await svc.get(UID)
+    assert draft is not None and [c.path for c in draft.changes] == ["b.py"] and draft.message == "feat: x"
+    await svc.clear(UID)
+    assert await svc.get(UID) is None
+
+
+async def test_expired_draft_is_gone(svc: DraftService) -> None:
+    await svc.put(UID, SHA, "a.py", ChangeOp.ADD, b"1")
+    Clock.now += timedelta(hours=25)
+    try:
+        assert await svc.get(UID) is None
+    finally:
+        Clock.now -= timedelta(hours=25)
+
+
+async def test_draft_size_limit(svc: DraftService) -> None:
+    for i in range(MAX_CHANGES):
+        await svc.put(UID, SHA, f"f{i}.py", ChangeOp.ADD, b"")
+    with pytest.raises(DraftFull):
+        await svc.put(UID, SHA, "one-more.py", ChangeOp.ADD, b"")
@@ -0,0 +1,74 @@
+import pytest
+
+from app.repo.validate import (
+    ValidationError,
+    check_content,
+    check_name,
+    diff_stat,
+    is_protected,
+    join,
+    python_syntax,
+    strip_fence,
+)
+
+
+@pytest.mark.parametrize("name", ["main.py", "a-b_c.1", ".gitignore", "X" * 100])
+def test_good_names(name: str) -> None:
+    assert check_name(f"  {name} ") == name
+
+
+@pytest.mark.parametrize("name", ["", ".", "..", "a/b", "привет.py", "a b", "X" * 101, "a;rm"])
+def test_bad_names(name: str) -> None:
+    with pytest.raises(ValidationError):
+        check_name(name)
+
+
+@pytest.mark.parametrize(
+    ("path", "protected"),
+    [
+        (".sourcecraft/ci.yaml", True),
+        (".tgit/x.py", True),
+        ("ruff.toml", True),
+        (".sourcecraft", True),
+        ("services/a/ruff.toml", False),
+        ("README.md", False),
+        ("services/a/main.py", False),
+    ],
+)
+def test_protected_paths(path: str, protected: bool) -> None:
+    assert is_protected(path) is protected
+
+
+def test_join() -> None:
+    assert join("", "a.py") == "a.py" and join("s/x", "a.py") == "s/x/a.py"
+
+
+@pytest.mark.parametrize(
+    ("text", "expected"),
+    [
+        ("```python\nprint(1)\n```", "print(1)"),
+        ("```\na\nb\n```", "a\nb"),
+        ("print(1)", "print(1)"),
+        ("x ``` y", "x ``` y"),
+    ],
+)
+def test_strip_fence(text: str, expected: str) -> None:
+    assert strip_fence(text) == expected
+
+
+def test_content_checks() -> None:
+    assert check_content("привет".encode()) == "привет"
+    for data, reason in [(b"a\0b", "binary"), (b"\xff\xfe", "encoding"), (b"x" * (100 * 1024 + 1), "too_big")]:
+        with pytest.raises(ValidationError, match=reason):
+            check_content(data)
+
+
+def test_python_syntax_only_for_py() -> None:
+    issue = python_syntax("a.py", "def f(:\n    pass\n")
+    assert issue is not None and issue.line == 1
+    assert python_syntax("a.py", "x = 1\n") is None
+    assert python_syntax("a.txt", "def f(:") is None
+
+
+def test_diff_stat() -> None:
+    assert diff_stat("a\nb\nc", "a\nB\nc\nd") == (2, 1)