Index Management

class Index:
    """
    Git index (staging area) for managing file changes.
    
    The index tracks file modifications, additions, and deletions
    between the working directory and repository commits.
    """
    
    def __init__(
        self,
        filename: Union[bytes, str, os.PathLike],
        read: bool = True,
        skip_hash: bool = False,
        version: Optional[int] = None,
    ):
        """
        Initialize index from file.
        
        Parameters:
        - filename: Path to index file (.git/index)
        - read: Whether to initialize from existing file
        - skip_hash: Whether to skip SHA1 hash when writing (for manyfiles feature)
        - version: Index format version to use (None = auto-detect)
        """
    
    def __getitem__(self, name: bytes) -> IndexEntry:
        """
        Get index entry by path.
        
        Parameters:
        - name: File path as bytes
        
        Returns:
        IndexEntry for the file
        
        Raises:
        KeyError: If file not in index
        """
    
    def __setitem__(self, name: bytes, entry: IndexEntry) -> None:
        """
        Set index entry for path.
        
        Parameters:
        - name: File path as bytes
        - entry: IndexEntry object
        """
    
    def __delitem__(self, name: bytes) -> None:
        """
        Remove entry from index.
        
        Parameters:
        - name: File path as bytes to remove
        """
    
    def __contains__(self, name: bytes) -> bool:
        """
        Check if path is in index.
        
        Parameters:
        - name: File path as bytes
        
        Returns:
        True if path exists in index
        """
    
    def __iter__(self) -> Iterator[bytes]:
        """
        Iterate over index paths.
        
        Yields:
        File paths as bytes
        """
    
    def __len__(self) -> int:
        """
        Get number of entries in index.
        
        Returns:
        Number of index entries
        """
    
    def clear(self) -> None:
        """Remove all entries from index."""
    
    def get_sha1(self, path: bytes) -> bytes:
        """
        Return the SHA-1 for the object at a path.
        
        Parameters:
        - path: File path as bytes
        
        Returns:
        SHA-1 hash of the object
        
        Raises:
        UnmergedEntries: If path has merge conflicts
        """
    
    def get_mode(self, path: bytes) -> int:
        """
        Return the POSIX file mode for the object at a path.
        
        Parameters:
        - path: File path as bytes
        
        Returns:
        File mode as integer
        
        Raises:
        UnmergedEntries: If path has merge conflicts
        """
    
    def iterobjects(self) -> Iterable[tuple[bytes, bytes, int]]:
        """
        Iterate over path, sha, mode tuples for use with commit_tree.
        
        Yields:
        Tuples of (path, sha, mode)
        
        Raises:
        UnmergedEntries: If index contains unmerged entries
        """
    
    def has_conflicts(self) -> bool:
        """
        Check if index contains merge conflicts.
        
        Returns:
        True if conflicts exist
        """
    
    def changes_from_tree(
        self,
        object_store: ObjectContainer,
        tree: ObjectID,
        want_unchanged: bool = False,
    ) -> Generator[
        tuple[
            tuple[Optional[bytes], Optional[bytes]],
            tuple[Optional[int], Optional[int]],
            tuple[Optional[bytes], Optional[bytes]],
        ],
        None,
        None,
    ]:
        """
        Find differences between index and tree.
        
        Parameters:
        - object_store: Object store for retrieving tree contents
        - tree: SHA-1 of the root tree
        - want_unchanged: Whether unchanged files should be reported
        
        Yields:
        Tuples with (oldpath, newpath), (oldmode, newmode), (oldsha, newsha)
        """
    
    def commit(self, object_store: ObjectContainer) -> bytes:
        """
        Create tree object from index contents.
        
        Parameters:
        - object_store: Object store for writing tree objects
        
        Returns:
        SHA-1 hash of created tree
        """
    
    def write(self) -> None:
        """Write index to disk."""
    
    def read(self) -> None:
        """Read index from disk."""
    
    @property
    def path(self) -> str:
        """
        Index file path.
        
        Returns:
        Path to index file
        """
    
    @property
    def version(self) -> int:
        """
        Index format version.
        
        Returns:
        Index format version number
        """

class IndexEntry:
    """
    Single entry in Git index representing staged file.
    
    Contains file metadata including timestamps, permissions,
    size, and SHA-1 hash of content.
    """
    
    def __init__(
        self,
        ctime: Tuple[int, int],
        mtime: Tuple[int, int], 
        dev: int,
        ino: int,
        mode: int,
        uid: int,
        gid: int,
        size: int,
        sha: bytes,
        flags: int = 0
    ):
        """
        Create index entry.
        
        Parameters:
        - ctime: Creation time as (seconds, nanoseconds)
        - mtime: Modification time as (seconds, nanoseconds)
        - dev: Device ID
        - ino: Inode number
        - mode: File mode/permissions
        - uid: User ID
        - gid: Group ID
        - size: File size in bytes
        - sha: 20-byte SHA-1 hash of content
        - flags: Index entry flags
        """
    
    @property
    def ctime(self) -> Tuple[int, int]:
        """
        Creation time.
        
        Returns:
        Tuple of (seconds, nanoseconds)
        """
    
    @property
    def mtime(self) -> Tuple[int, int]:
        """
        Modification time.
        
        Returns:
        Tuple of (seconds, nanoseconds)
        """
    
    @property
    def mode(self) -> int:
        """
        File mode/permissions.
        
        Returns:
        Unix file mode
        """
    
    @property
    def sha(self) -> bytes:
        """
        Content SHA-1 hash.
        
        Returns:
        20-byte SHA-1 hash
        """
    
    @property
    def size(self) -> int:
        """
        File size.
        
        Returns:
        File size in bytes
        """
    
    @property
    def flags(self) -> int:
        """
        Index entry flags.
        
        Returns:
        Flags indicating entry state
        """
    
    def stage(self) -> Stage:
        """
        Get the merge stage of this entry.
        
        Returns:
        Stage enum value
        """
    
    @property
    def skip_worktree(self) -> bool:
        """
        Return True if the skip-worktree bit is set.
        
        Returns:
        True if skip-worktree flag is set
        """
    
    def set_skip_worktree(self, skip: bool = True) -> None:
        """
        Set or clear the skip-worktree bit.
        
        Parameters:
        - skip: Whether to set the skip-worktree bit
        """
    
    @classmethod
    def from_serialized(cls, serialized: SerializedIndexEntry) -> "IndexEntry":
        """
        Create IndexEntry from serialized data.
        
        Parameters:
        - serialized: SerializedIndexEntry object
        
        Returns:
        IndexEntry object
        """
    
    def serialize(self, name: bytes, stage: Stage) -> SerializedIndexEntry:
        """
        Serialize entry for writing to index file.
        
        Parameters:
        - name: File path as bytes
        - stage: Merge stage
        
        Returns:
        SerializedIndexEntry object
        """

@dataclass
class SerializedIndexEntry:
    """
    Serialized representation of an index entry.
    
    Used during index file I/O operations to handle
    raw data before conversion to IndexEntry objects.
    """
    
    name: bytes
    ctime: Union[int, float, tuple[int, int]]
    mtime: Union[int, float, tuple[int, int]]
    dev: int
    ino: int
    mode: int
    uid: int
    gid: int
    size: int
    sha: bytes
    flags: int
    extended_flags: int
    
    def stage(self) -> Stage:
        """
        Get the merge stage of this entry.
        
        Returns:
        Stage enum value
        """

class Stage(Enum):
    """
    Merge conflict stage numbers.
    
    Used to identify different versions of files
    during merge operations.
    """
    
    NORMAL = 0
    MERGE_CONFLICT_ANCESTOR = 1
    MERGE_CONFLICT_THIS = 2
    MERGE_CONFLICT_OTHER = 3

class ConflictedIndexEntry:
    """
    Index entry representing merge conflict.
    
    Contains multiple versions of the same file from
    different merge parents requiring resolution.
    """
    
    ancestor: Optional[IndexEntry]
    this: Optional[IndexEntry]
    other: Optional[IndexEntry]
    
    def __init__(
        self,
        ancestor: Optional[IndexEntry] = None,
        this: Optional[IndexEntry] = None,
        other: Optional[IndexEntry] = None,
    ):
        """
        Create conflicted index entry.
        
        Parameters:
        - ancestor: Common ancestor version (stage 1)
        - this: Current branch version (stage 2)
        - other: Other branch version (stage 3)
        """

@dataclass
class IndexExtension:
    """
    Base class for index extensions.
    
    Extensions provide additional metadata stored
    in the Git index file format.
    """
    
    signature: bytes
    data: bytes
    
    @classmethod
    def from_raw(cls, signature: bytes, data: bytes) -> "IndexExtension":
        """
        Create extension from raw data.
        
        Parameters:
        - signature: 4-byte extension signature
        - data: Extension data
        
        Returns:
        Parsed extension object
        """
    
    def to_bytes(self) -> bytes:
        """
        Serialize extension to bytes.
        
        Returns:
        Extension data as bytes
        """

class TreeExtension(IndexExtension):
    """
    Tree cache extension for faster tree object creation.
    
    Caches tree SHA-1 values to avoid recalculation
    when creating tree objects from index.
    """
    
    def __init__(self, entries: list[tuple[bytes, bytes, int]]) -> None:
        """
        Initialize tree extension.
        
        Parameters:
        - entries: List of (path, sha, entry_count) tuples
        """

class ResolveUndoExtension(IndexExtension):
    """
    Resolve undo extension for recording merge conflicts.
    
    Stores information about resolved conflicts to allow
    undoing merge conflict resolution.
    """
    
    def __init__(self, entries: list[tuple[bytes, list[tuple[int, bytes]]]]) -> None:
        """
        Initialize resolve undo extension.
        
        Parameters:
        - entries: List of (path, [(stage, sha), ...]) tuples
        """

class UntrackedExtension(IndexExtension):
    """
    Untracked cache extension for faster status operations.
    
    Caches information about untracked files to speed up
    git status operations.
    """
    
    def __init__(self, data: bytes) -> None:
        """
        Initialize untracked extension.
        
        Parameters:
        - data: Raw extension data
        """

def read_index(filename: str) -> Index:
    """
    Read index from file.
    
    Parameters:
    - filename: Path to index file
    
    Returns:
    Index object loaded from file
    """

def write_index(filename: str, entries: Dict[bytes, IndexEntry]) -> None:
    """
    Write index entries to file.
    
    Parameters:
    - filename: Path to index file
    - entries: Dict mapping paths to IndexEntry objects
    """

def read_index_dict(filename: str) -> Dict[bytes, IndexEntry]:
    """
    Read index as dictionary.
    
    Parameters:
    - filename: Path to index file
    
    Returns:
    Dict mapping file paths to IndexEntry objects
    """

def write_index_dict(
    filename: str,
    entries: Dict[bytes, IndexEntry],
    version: int = 2
) -> None:
    """
    Write index dictionary to file.
    
    Parameters:
    - filename: Path to index file
    - entries: Dict mapping paths to IndexEntry objects
    - version: Index format version
    """

def commit_tree(
    object_store: BaseObjectStore,
    index: Dict[bytes, IndexEntry]
) -> bytes:
    """
    Create tree object from index entries.
    
    Parameters:
    - object_store: Object store for writing tree objects
    - index: Dict mapping paths to IndexEntry objects
    
    Returns:
    SHA-1 hash of created tree
    """

def commit_index(
    object_store: BaseObjectStore,
    index: Index
) -> bytes:
    """
    Create tree from Index object.
    
    Parameters:
    - object_store: Object store for writing objects
    - index: Index object
    
    Returns:
    SHA-1 hash of created tree
    """

def build_index_from_tree(
    object_store: BaseObjectStore,
    tree_id: bytes,
    honor_filemode: bool = True
) -> Dict[bytes, IndexEntry]:
    """
    Build index entries from tree object.
    
    Parameters:
    - object_store: Object store containing tree objects
    - tree_id: Tree SHA-1 hash
    - honor_filemode: Respect file mode from tree
    
    Returns:
    Dict mapping paths to IndexEntry objects
    """

def changes_from_tree(
    object_store: BaseObjectStore,
    index: Dict[bytes, IndexEntry],
    tree_id: bytes,
    want_unchanged: bool = False
) -> Iterator[Tuple[bytes, int, bytes]]:
    """
    Get changes between index and tree.
    
    Parameters:
    - object_store: Object store containing objects
    - index: Index entries to compare
    - tree_id: Tree SHA-1 hash to compare against
    - want_unchanged: Include unchanged files
    
    Yields:
    Tuples of (path, change_type, sha1_hash)
    """

def blob_from_path_and_stat(
    fs_path: bytes,
    st: os.stat_result,
    tree_encoding: str = "utf-8"
) -> Blob:
    """
    Create blob from filesystem path and stat.
    
    Parameters:
    - fs_path: Filesystem path to file
    - st: File stat information
    - tree_encoding: Encoding for tree paths
    
    Returns:
    Blob object
    """

def blob_from_path_and_mode(
    fs_path: bytes,
    mode: int,
    tree_encoding: str = "utf-8"
) -> Blob:
    """
    Create blob from filesystem path and mode.
    
    Parameters:
    - fs_path: Filesystem path to file
    - mode: File mode
    - tree_encoding: Encoding for tree paths
    
    Returns:
    Blob object
    """

def index_entry_from_stat(
    stat_val: os.stat_result,
    hex_sha: bytes,
    mode: Optional[int] = None,
) -> IndexEntry:
    """
    Create index entry from stat result.
    
    Parameters:
    - stat_val: POSIX stat_result
    - hex_sha: Hex SHA of the object
    - mode: Optional file mode override
    
    Returns:
    IndexEntry object
    """

def index_entry_from_path(
    path: bytes,
    object_store: Optional[ObjectContainer] = None
) -> Optional[IndexEntry]:
    """
    Create index entry from filesystem path.
    
    Parameters:
    - path: Path to create entry for
    - object_store: Optional object store for new blobs
    
    Returns:
    IndexEntry object or None for directories
    """

def update_working_tree(
    repo: "Repo",
    old_tree_id: Optional[bytes],
    new_tree_id: bytes,
    change_iterator: Iterator["TreeChange"],
    honor_filemode: bool = True,
    validate_path_element: Optional[Callable[[bytes], bool]] = None,
    symlink_fn: Optional[Callable] = None,
    force_remove_untracked: bool = False,
    blob_normalizer: Optional["BlobNormalizer"] = None,
    tree_encoding: str = "utf-8",
    allow_overwrite_modified: bool = False,
) -> None:
    """
    Update working tree and index to match a new tree.
    
    Parameters:
    - repo: Repository object
    - old_tree_id: SHA of tree before update
    - new_tree_id: SHA of tree to update to
    - change_iterator: Iterator of TreeChange objects
    - honor_filemode: Honor core.filemode setting
    - validate_path_element: Function to validate paths
    - symlink_fn: Function for creating symlinks
    - force_remove_untracked: Remove untracked files
    - blob_normalizer: Line ending normalizer
    - tree_encoding: Encoding for tree paths
    - allow_overwrite_modified: Allow overwriting modified files
    """

def get_unstaged_changes(
    index: Index,
    root_path: Union[str, bytes],
    filter_blob_callback: Optional[Callable] = None,
) -> Generator[bytes, None, None]:
    """
    Find paths with unstaged changes.
    
    Parameters:
    - index: Index to check
    - root_path: Root path to find files
    - filter_blob_callback: Optional blob filter
    
    Yields:
    Paths with unstaged changes
    """

def refresh_index(index: Index, root_path: bytes) -> None:
    """
    Refresh index contents from filesystem.
    
    Parameters:
    - index: Index to update
    - root_path: Root filesystem path
    """

class locked_index:
    """
    Context manager for locking index during modifications.
    
    Ensures atomic writes to the index file and proper
    cleanup if operations fail.
    """
    
    def __init__(self, path: Union[bytes, str]) -> None:
        """
        Initialize locked index.
        
        Parameters:
        - path: Path to index file
        """
    
    def __enter__(self) -> Index:
        """
        Enter context and return locked index.
        
        Returns:
        Index object ready for modification
        """
    
    def __exit__(
        self,
        exc_type: Optional[type],
        exc_value: Optional[BaseException],
        traceback: Optional[types.TracebackType],
    ) -> None:
        """
        Exit context and write/abort changes.
        
        Parameters:
        - exc_type: Exception type if any
        - exc_value: Exception value if any
        - traceback: Exception traceback if any
        """

class UnsupportedIndexFormat(Exception):
    """
    Raised when index format version is not supported.
    
    Occurs when trying to read index with newer format
    version than supported by current dulwich version.
    """
    
    def __init__(self, version: int) -> None:
        """
        Initialize exception.
        
        Parameters:
        - version: Unsupported index format version
        """

class UnmergedEntries(Exception):
    """
    Raised when index contains unmerged entries.
    
    Occurs during operations that require clean index
    but merge conflicts exist.
    """

from dulwich.index import (
    Index, IndexEntry, locked_index, 
    build_index_from_tree, update_working_tree
)
from dulwich.objects import Blob
from dulwich.repo import Repo
import os

# Open repository index
index = Index("/path/to/repo/.git/index")

# Check if file is staged
if b"file.txt" in index:
    entry = index[b"file.txt"]
    print(f"File SHA-1: {entry.sha.hex()}")
    print(f"File size: {entry.size}")
    print(f"Stage: {entry.stage()}")

# Stage new file using locked context
with locked_index("/path/to/repo/.git/index") as index:
    stat_result = os.stat("/path/to/file.txt")
    entry = IndexEntry(
        ctime=(int(stat_result.st_ctime), 0),
        mtime=(int(stat_result.st_mtime), 0),
        dev=stat_result.st_dev,
        ino=stat_result.st_ino,
        mode=stat_result.st_mode,
        uid=stat_result.st_uid,
        gid=stat_result.st_gid,
        size=stat_result.st_size,
        sha=b"new_blob_sha_here",
        flags=0
    )
    index[b"file.txt"] = entry
    # Index automatically written on context exit

# Build index from tree
repo = Repo("/path/to/repo")
build_index_from_tree(
    "/path/to/worktree",
    "/path/to/repo/.git/index", 
    repo.object_store,
    b"tree_sha_here"
)

# Create tree from index
tree_sha = index.commit(repo.object_store)
print(f"Tree SHA-1: {tree_sha.hex()}")

# Check for conflicts
if index.has_conflicts():
    print("Index has merge conflicts")
    for path in index:
        entry = index[path]
        if isinstance(entry, ConflictedIndexEntry):
            print(f"Conflict in {path.decode()}:")
            if entry.ancestor:
                print(f"  Ancestor: {entry.ancestor.sha.hex()}")
            if entry.this:
                print(f"  This: {entry.this.sha.hex()}")
            if entry.other:
                print(f"  Other: {entry.other.sha.hex()}")