File unlocks are atomic again via rename. Read-only files on Windows are made read-write if necessary.
Share open packfiles across repositories to share descriptors and mmaps.
Use a map for the treebuilder, making insertion O(1)
Introduce reference transactions, which allow multiple references to be locked at the same time and updates be queued. This also allows us to safely update a reflog with arbitrary contents, as we need to do for stash.
The index' tree cache is now filled upon read-tree and write-tree and the cache is written to disk.
LF -> CRLF filter refuses to handle mixed-EOL files
LF -> CRLF filter now runs when * text = auto (with Git for Windows 1.9.4)
The git_transport structure definition has moved into the sys/transport.h file.
The ssh transport supports asking the remote host for accepted credential types as well as multiple challeges using a single connection. This requires to know which username you want to connect as, so this introduces the USERNAME credential type which the ssh transport will use to ask for the username.
The build system now accepts an option EMBED_SSH_PATH which when set tells it to include a copy of libssh2 at the given location. This is enabled for MSVC.
libgit2 no longer automatically sets the OpenSSL locking functions. This is not something which we can know to do. A last-resort convenience function is provided in sys/openssl.h, git_openssl_set_locking() which can be used to set the locking.
The git_transport_register function no longer takes a priority and takes a URL scheme name (eg “http”) instead of a prefix like “http://”
The git_remote_set_transport function now sets a transport factory function, rather than a pre-existing transport instance.
A factory function for ssh has been added which allows to change the path of the programs to execute for receive-pack and upload-pack on the server, git_transport_ssh_with_paths.
git_remote_rename() now takes the repository and the remote's current name. Accepting a remote indicates we want to change it, which we only did partially. It is much clearer if we accept a name and no loaded objects are changed.
git_remote_delete() now accepts the repository and the remote's name instead of a loaded remote.
git_remote_supported_url() has been removed as it has become essentially useless with rsync-style ssh paths.
The git_clone_options struct no longer provides the ignore_cert_errors or remote_name members for remote customization.
Instead, the git_clone_options struct has two new members, remote_cb and remote_cb_payload, which allow the caller to completely override the remote creation process. If needed, the caller can use this callback to give their remote a name other than the default (origin) or disable cert checking.
The remote_callbacks member has been preserved for convenience, although it is not used when a remote creation callback is supplied.
The git_clone_options struct now provides repository_cb and repository_cb_payload to allow the user to create a repository with custom options.
The option to ignore certificate errors via git_remote_cert_check() is no longer present. Instead, git_remote_callbacks has gained a new entry which lets the user perform their own certificate checks.
git_clone_into and git_clone_local_into have been removed from the public API in favour of git_clone callbacks
Add support for refspecs with the asterisk in the middle of a pattern.
Fetching now performs opportunistic updates. To achieve this, we introduce a difference between active and passive refspecs, which make git_remote_download and git_remote_fetch to take a list of resfpecs to be the active list, similarly to how git fetch accepts a list on the command-line.
Rename git_remote_load() to git_remote_lookup() to bring it in line with the rest of the lookup functions.
The git_push struct to perform a push has been replaced with git_remote_upload(). The refspecs and options are passed as a function argument. git_push_update_tips() is now also git_remote_update_tips() and the callbacks are in the same struct as the rest.
Introduce git_merge_bases() and the git_oidarray type to expose all merge bases between two commits.
Introduce git_merge_bases_many() to expose all merge bases between multiple commits.
git_merge_head is now git_annotated_commit, to better reflect its usage for multiple functions (including rebase)
Introduce rebase functionality (using the merge algorithm only). Introduce git_rebase_init() to begin a new rebase session, git_rebase_open() to open an in-progress rebase session, git_rebase_commit() to commit the current rebase operation, git_rebase_next() to apply the next rebase operation, git_rebase_abort() to abort an in-progress rebase and git_rebase_finish() to complete a rebase operation.
Introduce git_note_author() and git_note_committer() to get the author and committer information on a git_note, respectively.
git_note_create() has changed the position of the notes reference name to match git_note_remove().
The THREADSAFE option to build libgit2 with threading support has been flipped to be on by default.
The context_lines and interhunk_lines fields in git_diff_options are now uint32_t instead of uint16_t. This allows to set them to UINT_MAX, in effect asking for “infinite” context e.g. to iterate over all the unmodified lines of a diff.
git_status_file now takes an exact path. Use git_status_list_new if pathspec searching is needed.
The fetch behavior of remotes with autotag set to GIT_REMOTE_DOWNLOAD_TAGS_ALL has been changed to match git 1.9.0 and later. In this mode, libgit2 now fetches all tags in addition to whatever else needs to be fetched.
The remote object has learnt to prune remote-tracking branches. If the remote is configured to do so, this will happen via git_remote_fetch(). You can also call git_remote_prune() after connecting or fetching to perform the prune.
git_threads_init() and git_threads_shutdown() have been renamed to git_libgit2_init() and git_libgit2_shutdown() to better explain what their purpose is, as it's grown to be more than just about threads.
git_libgit2_init() and git_libgit2_shutdown() now return the number of initializations of the library, so consumers may schedule work on the first initialization.
git_treebuilder_new (was git_treebuilder_create) now takes a repository so that it can query repository configuration. Subsequently, git_treebuilder_write no longer takes a repository.
git_treebuilder_create was renamed to git_treebuilder_new to better reflect it being a constructor rather than something which writes to disk.
git_checkout now handles case-changing renames correctly on case-insensitive filesystems; for example renaming “readme” to “README”.
git_index_name_entrycount() and git_index_reuc_entrycount() now return size_t instead of unsigned int.
The search for libssh2 is now done via pkg-config instead of a custom search of a few directories.
Add support for core.protectHFS and core.protectNTFS. Add more validation for filenames which we write such as references.
The local transport now generates textual progress output like git-upload-pack does (“counting objects”).