pygit 2 snippets - most examples assume using a bare repository.

commit.py

import pygit2

# open existing repository
repo = pygit2.Repository(pygit2.discover_repository('test_repos'))

# check if repos is newly created
if repo.head_is_unborn:
    tb = repo.TreeBuilder()
    parent = []
else:
    tb = repo.TreeBuilder(repo.head.peel().tree.id)
    parent = [repo.head.target]

# add file from anywhere on disk
blob_id = repo.create_blob_fromdisk("/path/to/file")

# insert into tree, and get current tree
# CAVEAT: when adding to a nested path, will need to walk the whole tree inserting new trees
# to get back their oid, and from that oid continue all operations. all operations are "nested", so,
# you will need to grab the last tree from TreeBuilder.write() to make the next change.
# https://gist.github.com/uniphil/9570964 illustrates how to do it, from method auto_insert()
# deleting from a nested path would also require walking the entire tree, like in auto_insert(), but, replacing
# the treebuilder.insert() from the base case to a treebuilder.remove().
tb.insert('file', blob_id, pygit2.GIT_FILEMODE_BLOB)
tree = tb.write()

# add blob from any data
new_blob_id = repo.create_blob('foobar');

# needs to get another treebuilder based on last operation
tb = repo.TreeBuilder(tree)
tb.insert('other_file', new_blob_id, pygit2.GIT_FILEMODE_BLOB)
tree = tb.write()

# delete a file
tb = repo.TreeBuilder(tree)
tb.remove('old_file')
tree = tb.write()

# write to index
repo.index.write()

# author of commit
author = pygit2.Signature('Author', 'author@email.com')

# commit changes
oid = repo.create_commit('refs/heads/master', author, author, 'commit message', tree, parent)

create_branch.py

import pygit2

# open existing repository
repo = pygit2.Repository(pygit2.discover_repository('test_repos'))

# read index
repo.index.read()

# create branch from master
branch = repo.create_branch('new_branch', repo.head.peel())

# or create from another branch
other_branch = repo.lookup_branch('other_branch')
branch = repo.create_branch('new_branch', other_branch.peel())

in_memory_diff.py

import pygit2

# open existing repository
repo = pygit2.Repository(pygit2.discover_repository('test_repos'))

# branch against tree
branch = repo.lookup_branch('some_branch')
# master would be: repo.head.peel().tree
tree = branch.peel().tree

# use an in-memory index and read current tree
index = pygit2.Index()
index.read_tree(tree)

# add data
blob_id = repo.create_blob('foobar')
entry = pygit2.IndexEntry('full/path/to/file', blob_id, pygit2.GIT_FILEMODE_BLOB)
index.add(entry)

# can now check for conflicts
index.conflicts

# generate diff from current tree to in-memory index
diff = tree.diff_to_index(index)

# diff patch
patch = diff.patch

init_and_clone_repository.py

import pygit2

# bare repository
repo = pygit2.init_repository('test_repos', True)

# normal repository
repo = pygit2.init_repository('test_repos')

# clone repository
repo = pygit2.clone_repository('path_or_remote_host', 'new_cloned_repo', bare=True)

open_repository.py

import pygit2

# open existing repository
repo = pygit2.Repository(pygit2.discover_repository('test_repos'))

read_commits.py

import pygit2

# open existing repository
repo = pygit2.Repository(pygit2.discover_repository('test_repos'))

# read index
repo.index.read()

for commit in repo.walk(repo.head.target, pygit2.GIT_SORT_TOPOLOGICAL):
    parent_oid = None

    if len(commit.parents) > 0:
        parent_oid = commit.parents[0].oid

    print("{} commit: {} - parents: {}".format(commit.oid, commit.message.strip(), parent_oid))