Objects

There are four types of Git objects: blobs, trees, commits and tags. For each one pygit2 has a type, and all four types inherit from the base Object type.

Contents

Object lookup
The Object base type
Blobs
- Creating blobs
Trees
- Creating trees
Commits
- Signatures
- Creating commits
Tags
- Creating tags

Object lookup 

In the previous chapter we learnt about Object IDs. With an Oid we can ask the repository to get the associated object. To do that the Repository class implementes a subset of the mapping interface.

class pygit2.Repository(path=None, flags=0)

get(key, default=None)

Return the Git object for the given id, returns the default value if there’s no object in the repository with that id. The id can be an Oid object, or an hexadecimal string.

Example:

>>> from pygit2 import Repository
>>> repo = Repository('path/to/pygit2')
>>> obj = repo.get("101715bf37440d32291bde4f58c3142bcf7d8adb")
>>> obj
<_pygit2.Commit object at 0x7ff27a6b60f0>

__getitem__(id): Return the Git object for the given id, raise KeyError if there’s no object in the repository with that id. The id can be an Oid object, or an hexadecimal string.

__contains__(id): Returns True if there is an object in the Repository with that id, False if there is not. The id can be an Oid object, or an hexadecimal string.

The Object base type 

The Object type is a base type, it is not possible to make instances of it, in any way.

It is the base type of the Blob, Tree, Commit and Tag types, so it is possible to check whether a Python value is an Object or not:

>>> from pygit2 import Object
>>> commit = repository.revparse_single('HEAD')
>>> print(isinstance(commit, Object))
True

All Objects are immutable, they cannot be modified once they are created:

>>> commit.message = u"foobar"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: attribute 'message' of '_pygit2.Commit' objects is not writable

Derived types (blobs, trees, etc.) don’t have a constructor, this means they cannot be created with the common idiom:

>>> from pygit2 import Blob
>>> blob = Blob("data")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot create '_pygit2.Blob' instances

New objects are created using an specific API we will see later.

This is the common interface for all Git objects:

class pygit2.Object

Base class for Git objects.

__eq__(value, /): Return self==value.

__hash__(): Return hash(self).

__ne__(value, /): Return self!=value.

__repr__(): Return repr(self).

filemode: Filemode (will be None if the object was not reached trough a tree)

id: The object id, an instance of the Oid type.

name: Name (will be None if the object was not reached trough a tree)

peel(target_type) → Object

Peel the current object and returns the first object of the given type.

If you pass None as the target type, then the object will be peeled until the type changes. A tag will be peeled until the referenced object is no longer a tag, and a commit will be peeled to a tree. Any other object type will raise InvalidSpecError.

read_raw() → bytes: Returns the byte string with the raw contents of the object.

short_id: An unambiguous short (abbreviated) hex Oid string for the object.

type: One of the GIT_OBJ_COMMIT, GIT_OBJ_TREE, GIT_OBJ_BLOB or GIT_OBJ_TAG constants.

type_str: One of the ‘commit’, ‘tree’, ‘blob’ or ‘tag’ strings.

Blobs 

A blob is just a raw byte string. They are the Git equivalent to files in a filesytem.

This is their API:

class pygit2.Blob

Blob object.

Blobs implement the buffer interface, which means you can get access to its data via memoryview(blob) without the need to create a copy.

data

The contents of the blob, a byte string. This is the same as Blob.read_raw().

Example, print the contents of the .gitignore file:

>>> blob = repo['d8022420bf6db02e906175f64f66676df539f2fd']
>>> print(blob.data)
MANIFEST
build
dist

diff([blob: Blob, flag: int = GIT_DIFF_NORMAL, old_as_path: str, new_as_path: str]) → Patch

Directly generate a pygit2.Patch from the difference between two blobs.

Returns: Patch.

Parameters:

blobBlob: The Blob to diff.
flag: A GIT_DIFF_* constant.
old_as_pathstr: Treat old blob as if it had this filename.
new_as_pathstr: Treat new blob as if it had this filename.

diff_to_buffer(buffer: bytes = None, flag: int = GIT_DIFF_NORMAL[, old_as_path: str, buffer_as_path: str]) → Patch

Directly generate a Patch from the difference between a blob and a buffer.

Returns: Patch.

Parameters:

bufferbytes: Raw data for new side of diff.
flag: A GIT_DIFF_* constant.
old_as_pathstr: Treat old blob as if it had this filename.
buffer_as_pathstr: Treat buffer as if it had this filename.

is_binary: True if binary data, False if not.

size

Size in bytes.

Example:

>>> print(blob.size)
130

Creating blobs 

There are a number of methods in the repository to create new blobs, and add them to the Git object database:

class pygit2.Repository(path=None, flags=0)

create_blob(data: bytes) → Oid

Create a new blob from a bytes string. The blob is added to the Git object database. Returns the oid of the blob.

Example:

>>> id  = repo.create_blob('foo bar')   # Creates blob from a byte string
>>> blob = repo[id]
>>> blob.data
'foo bar'

create_blob_fromdisk(path: str) → Oid: Create a new blob from a file anywhere (no working directory check).

create_blob_fromiobase(io.IOBase) → Oid: Create a new blob from an IOBase object.

create_blob_fromworkdir(path: str) → Oid: Create a new blob from a file within the working directory. The given path must be relative to the working directory, if it is not an error is raised.

There are also some functions to calculate the id for a byte string without creating the blob object:

pygit2.hash(data: bytes) → Oid: Returns the oid of a new blob from a string without actually writing to the odb.

pygit2.hashfile(path: str) → Oid: Returns the oid of a new blob from a file path without actually writing to the odb.

Trees 

At the low level (libgit2) a tree is a sorted collection of tree entries. In pygit2 accessing an entry directly returns the object.

A tree can be iterated, and partially implements the sequence and mapping interfaces.

class pygit2.Tree

Tree objects.

__getitem__(name)

Tree[name]

Return the Object subclass instance for the given name. Raise KeyError if there is not a tree entry with that name.

__truediv__(name)

Tree / name

Return the Object subclass instance for the given name. Raise KeyError if there is not a tree entry with that name. This allows navigating the tree similarly to Pathlib using the slash operator via.

Example:

>>> entry = tree / 'path' / 'deeper' / 'some.file'

__contains__(name)

name in Tree

Return True if there is a tree entry with the given name, False otherwise.

__len__()

len(Tree)

Return the number of objects in the tree.

__iter__()

for object in Tree

Return an iterator over the objects in the tree.

diff_to_index(index: Index, flags: int = GIT_DIFF_NORMAL, context_lines: int = 3, interhunk_lines: int = 0) → Diff

Show the changes between the index and a given Tree.

Parameters:

indexIndex: The index to diff.
flag: A GIT_DIFF_* constant.
context_lines: The number of unchanged lines that define the boundary of a hunk (and to display before and after).
interhunk_lines: The maximum number of unchanged lines between hunk boundaries before the hunks will be merged into a one.

diff_to_tree([tree: Tree, flags: int = GIT_DIFF_NORMAL, context_lines: int = 3, interhunk_lines: int = 0, swap: bool = False]) → Diff

Show the changes between two trees.

Parameters:

tree: Tree: The tree to diff. If no tree is given the empty tree will be used instead.
flag: A GIT_DIFF_* constant.
context_lines: The number of unchanged lines that define the boundary of a hunk (and to display before and after).
interhunk_lines: The maximum number of unchanged lines between hunk boundaries before the hunks will be merged into a one.
swap: Instead of diffing a to b. Diff b to a.

diff_to_workdir(flags: int = GIT_DIFF_NORMAL, context_lines: int = 3, interhunk_lines: int = 0) → Diff

Show the changes between the Tree and the workdir.

Parameters:

flag: A GIT_DIFF_* constant.
context_lines: The number of unchanged lines that define the boundary of a hunk (and to display before and after).
interhunk_lines: The maximum number of unchanged lines between hunk boundaries before the hunks will be merged into a one.

Example:

>>> tree = commit.tree
>>> len(tree)                        # Number of entries
6

>>> for obj in tree:                 # Iteration
...     print(obj.id, obj.type_str, obj.name)
...
7151ca7cd3e59f3eab19c485cfbf3cb30928d7fa blob .gitignore
c36f4cf1e38ec1bb9d9ad146ed572b89ecfc9f18 blob COPYING
32b30b90b062f66957d6790c3c155c289c34424e blob README.md
c87dae4094b3a6d10e08bc6c5ef1f55a7e448659 blob pygit2.c
85a67270a49ef16cdd3d328f06a3e4b459f09b27 blob setup.py
3d8985bbec338eb4d47c5b01b863ee89d044bd53 tree test

>>> obj = tree / 'pygit2.c'          # Get an object by name
>>> obj
<_pygit2.Blob at 0x7f08a70acc10>

Creating trees 

class pygit2.Repository(path=None, flags=0)

TreeBuilder([tree]) → TreeBuilder: Create a TreeBuilder object for this repository.

class pygit2.TreeBuilder

TreeBuilder objects.

clear(): Clear all the entries in the builder.

get(name: str) → Object: Return the Object for the given name, or None if there is not.

insert(name: str, oid: Oid, attr: int)

Insert or replace an entry in the treebuilder.

Parameters:

attr: Available values are GIT_FILEMODE_BLOB, GIT_FILEMODE_BLOB_EXECUTABLE, GIT_FILEMODE_TREE, GIT_FILEMODE_LINK and GIT_FILEMODE_COMMIT.

remove(name: str): Remove an entry from the builder.

write() → Oid: Write the tree to the given repository.

Commits 

A commit is a snapshot of the working dir with meta informations like author, committer and others.

class pygit2.Commit

Commit objects.

author: The author of the commit.

commit_time: Commit time.

commit_time_offset: Commit time offset.

committer: The committer of the commit.

gpg_signature: A tuple with the GPG signature and the signed payload.

message: The commit message, a text string.

message_encoding: Message encoding.

message_trailers: Returns commit message trailers (e.g., Bug: 1234) as a dictionary.

parent_ids: The list of parent commits’ ids.

parents: The list of parent commits.

raw_message: Message (bytes).

tree: The tree object attached to the commit.

tree_id: The id of the tree attached to the commit.

Signatures 

The author and committer attributes of commit objects are Signature objects:

>>> commit.author
pygit2.Signature('Foo Ibáñez', 'foo@example.com', 1322174594, 60, 'utf-8')

Signatures can be compared for (in)equality.

class pygit2.Signature

Signature.

email: Email address.

name: Name.

offset: Offset from UTC in minutes.

raw_email: Email (bytes).

raw_name: Name (bytes).

time: Unix time.

Creating commits 

class pygit2.Repository(path=None, flags=0)

create_commit(reference_name: str, author: Signature, committer: Signature, message: bytes | str, tree: Oid, parents: list[Oid][, encoding: str]) → Oid: Create a new commit object, return its oid.

Commits can be created by calling the create_commit method of the repository with the following parameters:

>>> author = Signature('Alice Author', 'alice@authors.tld')
>>> committer = Signature('Cecil Committer', 'cecil@committers.tld')
>>> tree = repo.TreeBuilder().write()
>>> repo.create_commit(
... 'refs/heads/master', # the name of the reference to update
... author, committer, 'one line commit message\n\ndetailed commit message',
... tree, # binary string representing the tree object ID
... [] # list of binary strings representing parents of the new commit
... )
'#\xe4<u\xfe\xd6\x17\xa0\xe6\xa2\x8b\xb6\xdc35$\xcf-\x8b~'

Tags 

A tag is a static label for a commit. See references for more information.

class pygit2.Tag

Tag objects.

get_object() → object: Retrieves the object the current tag is pointing to.

message: Tag message.

name: Tag name.

raw_message: Tag message (bytes).

raw_name: Tag name (bytes).

tagger: Tagger.

target: Tagged object.

Creating tags 

class pygit2.Repository(path=None, flags=0)

create_tag(name: str, oid: Oid, type: int, tagger: Signature[, message: str]) → Oid: Create a new tag object, return its oid.