libgit2 v0.99.0

This is v0.99 "Torschlusspanik". This will be the last minor release
before libgit2 v1.0. We expect to only respond to bugs in this release,
to stabilize it for next major release.

It contains significant refactorings, but is expected to be API-compatible
with v0.28.0.

Changes or improvements

• When fetching from an anonymous remote using a URL with authentication
  information provided in the URL (eg https://foo:bar@example.com/repo),
  we would erroneously include the literal URL in the FETCH_HEAD file.
  We now remove that to match git's behavior.

• Some credential structures, enums and values have been renamed:
  git_cred is now git_credential. git_credtype_t is now
  git_credential_t. Functions and types beginning with
  git_cred_ now begin with git_credential, and constants beginning
  with GIT_CREDTYPE now begin with GIT_CREDENTIAL. The former names
  are deprecated.

• Several function signatures have been changed to return an int to
  indicate error conditions. We encourage you to check them for errors
  in the standard way.

  • git_attr_cache_flush
  • git_error_set_str
  • git_index_name_clear
  • git_index_reuc_clear
  • git_libgit2_version
  • git_mempack_reset
  • git_oid_cpy
  • git_oid_fmt
  • git_oid_fromraw
  • git_oid_nfmt
  • git_oid_pathfmt
  • git_remote_stop
  • git_remote_disconnect
  • git_repository__cleanup
  • git_repository_set_config
  • git_repository_set_index
  • git_repository_set_odb
  • git_repository_set_refdb
  • git_revwalk_reset
  • git_revwalk_simplify_first_parent
  • git_revwalk_sorting
  • git_treebuilder_clear
  • git_treebuilder_filter

• The NTLM and Negotiate authentication mechanisms are now supported when
  talking to git implementations hosted on Apache or nginx servers.

• The HEAD symbolic reference can no longer be deleted.

• git_merge_driver_source_repo no longer returns a const git_repository *,
  it now returns a non-const git_repository *.

• Relative symbolic links are now supported on Windows when core.symlinks
  is enabled.

• Servers that provide query parameters with a redirect are now supported.

• git_submodule_sync will now resolve relative URLs.

• When creating git endpoint URLs, double-slashes are no longer used when
  the given git URL has a trailing slash.

• On Windows, a DllMain function is no longer included and thread-local
  storage has moved to fiber-local storage in order to prevent race
  conditions during shutdown.

• The tracing mechanism (GIT_TRACE) is now enabled by default and does
  not need to be explicitly enabled in CMake.

• The size of Git objects is now represented by git_object_size_t
  instead of off_t.

• Binary patches without data can now be parsed.

• A configuration snapshot can now be created from another configuration
  snapshot, not just a "true" configuration object.

• The git_commit_with_signature API will now ensure that referenced
  objects exist in the object database.

• Stash messages containing newlines will now be replaced with spaces;
  they will no longer be (erroneously) written to the repository.

• git_commit_create_with_signature now verifies the commit information
  to ensure that it points to a valid tree and valid parents.

• git_apply has an option GIT_APPLY_CHECK that will only do a dry-run.
  The index and working directory will remain unmodified, and application
  will report if it would have worked.

• Patches produced by Mercurial (those that lack some git extended headers)
  can now be parsed and applied.

• Reference locks are obeyed correctly on POSIX platforms, instead of
  being removed.

• Patches with empty new files can now be read and applied.

• git_apply_to_tree can now correctly apply patches that add new files.

• The program data configuration on Windows (C:\ProgramData\Git\config)
  must be owned by an administrator, a system account or the current user
  to be read.

• git_blob_filtered_content is now deprecated in favor of git_blob_filter.

• Configuration files can now be included conditionally using the
  onbranch conditional.

• Checkout can now properly create and remove symbolic links to directories
  on Windows.

• Stash no longer recomputes trees when committing a worktree, for
  improved performance.

• Repository templates can now include a HEAD file to default the
  initial default branch.

• Some configuration structures, enums and values have been renamed:
  git_cvar_map is now git_configmap, git_cvar_t is now
  git_configmap_t, GIT_CVAR_FALSE is now GIT_CONFIGMAP_FALSE,
  GIT_CVAR_TRUE is now GIT_CONFIGMAP_TRUE, GIT_CVAR_INT32 is now
  GIT_CONFIGMAP_INT32, and GIT_CVAR_STRING is now GIT_CONFIGMAP_STRING.
  The former names are deprecated.

• Repositories can now be created at the root of a Windows drive.

• Configuration lookups are now more efficiently cached.

• git_commit_create_with_signature now supports a NULL signature,
  which will create a commit without adding a signature.

• When a repository lacks an info "common directory", we will no
  longer erroneously return GIT_ENOTFOUND for all attribute lookups.

• Several attribute macros have been renamed: GIT_ATTR_TRUE is now
  GIT_ATTR_IS_TRUE, GIT_ATTR_FALSE is now GIT_ATTR_IS_FALSE,
  GIT_ATTR_UNSPECIFIED is now GIT_ATTR_IS_UNSPECIFIED. The
  attribute enum git_attr_t is now git_attr_value_t and its
  values have been renamed: GIT_ATTR_UNSPECIFIED_T is now
  GIT_ATTR_VALUE_UNSPECIFIED, GIT_ATTR_TRUE_T is now
  GIT_ATTR_VALUE_TRUE, GIT_ATTR_FALSE_T is now GIT_ATTR_VALUE_FALSE,
  and GIT_ATTR_VALUE_T is now GIT_ATTR_VALUE_STRING. The
  former names are deprecated.

• git_object__size is now git_object_size. The former name is
  deprecated.

• git_tag_create_frombuffer is now git_tag_create_from_buffer. The
  former name is deprecated.

• Several blob creation functions have been renamed:
  git_blob_create_frombuffer is now named git_blob_create_from_buffer,
  git_blob_create_fromdisk is now named git_blob_create_from_disk,
  git_blob_create_fromworkdir is now named git_blob_create_from_workdir,
  git_blob_create_fromstream is now named git_blob_create_from_stream,
  and git_blob_create_fromstream_commit is now named
  git_blob_create_from_stream_commit. The former names are deprecated.

• The function git_oid_iszero is now named git_oid_is_zero. The
  former name is deprecated.

• Pattern matching is now done using wildmatch instead of fnmatch
  for compatibility with git.

• The option initialization functions suffixed by init_options are now
  suffixed with options_init. (For example, git_checkout_init_options
  is now git_checkout_options_init.) The former names are deprecated.

• NTLM2 authentication is now supported on non-Windows platforms.

• The git_cred_sign_callback callback is now named git_cred_sign_cb.
  The git_cred_ssh_interactive_callback callback is now named
  git_cred_ssh_interactive_cb.

• Ignore files now:

  • honor escaped trailing whitespace.
  • do not incorrectly negate sibling paths of a negated pattern.
  • honor rules that stop ignoring files after a wildcard

• Attribute files now:

  • honor leading and trailing whitespace.
  • treat paths beginning with \ as absolute only on Windows.
  • properly handle escaped characters.
  • stop reading macros defined in subdirectories

• The C locale is now correctly used when parsing regular expressions.

• The system PCRE2 or PCRE regular expression libraries are now used
  when regcomp_l is not available on the system. If none of these
  are available on the system, an included version of PCRE is used.

• Wildcards in reference specifications are now supported beyond simply
  a bare wildcard (*) for compatibility with git.

• When git_ignore_path_is_ignored is provided a path with a trailing
  slash (eg, dir/), it will now treat it as a directory for the
  purposes of ignore matching.

• Patches that add or remove a file with a space in the path can now
  be correctly parsed.

• The git_remote_completion_type type is now git_remote_completion_t.
  The former name is deprecated.

• The git_odb_backend_malloc is now git_odb_backend_data_alloc. The
  former name is deprecated.

• The git_transfer_progress_cb callback is now git_indexer_progress_cb
  and the git_transfer_progress structure is now git_indexer_progress.
  The former names are deprecated.

• The example projects are now contained in a single lg2 executable
  for ease of use.

• libgit2 now correctly handles more URLs, such as
  http://example.com:/repo.git (colon but no port),
  http://example.com (no path),
  and http://example.com:8080/ (path is /, nonstandard port).

• A carefully constructed commit object with a very large number
  of parents may lead to potential out-of-bounds writes or
  potential denial of service.

• The ProgramData configuration file is always read for compatibility
  with Git for Windows and Portable Git installations. The ProgramData
  location is not necessarily writable only by administrators, so we
  now ensure that the configuration file is owned by the administrator
  or the current user.

API additions

• The SSH host key now supports SHA-256 when GIT_CERT_SSH_SHA256 is set.

• The diff format option GIT_DIFF_FORMAT_PATCH_ID can now be used to
  emit an output like git patch-id.

• The git_apply_options_init function will initialize a
  git_apply_options structure.

• The remote callbacks structure adds a git_url_resolve_cb callback
  that is invoked when connecting to a server, so that applications
  may edit or replace the URL before connection.

• The information about the original HEAD in a rebase operation is
  available with git_rebase_orig_head_name. Its ID is available with
  git_rebase_orig_head_id. The onto reference name is available with
  git_rebase_onto_name and its ID is available with git_rebase_onto_id.

• ODB backends can now free backend data when an error occurs during its
  backend data creation using git_odb_backend_data_free.

• Options may be specified to git_repository_foreach_head to control
  its behavior: GIT_REPOSITORY_FOREACH_HEAD_SKIP_REPO will not skip
  the main repository's HEAD reference, while
  GIT_REPOSITORY_FOREACH_HEAD_SKIP_WORKTREES will now skip the
  worktree HEAD references.

• The GIT_OPT_DISABLE_PACK_KEEP_FILE_CHECKS option can be specified to
  git_libgit2_opts() to avoid looking for .keep files that correspond
  to packfiles. This setting can improve performance when packfiles are
  stored on high-latency filesystems like network filesystems.

• Blobs can now be filtered with git_blob_filter, which allows for
  options to be set with git_blob_filter_options, including
  GIT_FILTER_NO_SYSTEM_ATTRIBUTES to disable filtering with system-level
  attributes in /etc/gitattributes and GIT_ATTR_CHECK_INCLUDE_HEAD to
  enable filtering with .gitattributes files in the HEAD revision.

API removals

• The unused git_headlist_cb function declaration was removed.

• The unused git_time_monotonic API is removed.

• The erroneously exported inttypes.h header was removed.

Security Fixes

• CVE-2019-1348: the fast-import stream command "feature
  export-marks=path" allows writing to arbitrary file paths. As
  libgit2 does not offer any interface for fast-import, it is not
  susceptible to this vulnerability.

• CVE-2019-1349: by using NTFS 8.3 short names, backslashes or
  alternate filesystreams, it is possible to cause submodules to
  be written into pre-existing directories during a recursive
  clone using git. As libgit2 rejects cloning into non-empty
  directories by default, it is not susceptible to this
  vulnerability.

• CVE-2019-1350: recursive clones may lead to arbitrary remote
  code executing due to improper quoting of command line
  arguments. As libgit2 uses libssh2, which does not require us
  to perform command line parsing, it is not susceptible to this
  vulnerability.

• CVE-2019-1351: Windows provides the ability to substitute
  drive letters with arbitrary letters, including multi-byte
  Unicode letters. To fix any potential issues arising from
  interpreting such paths as relative paths, we have extended
  detection of DOS drive prefixes to accomodate for such cases.

• CVE-2019-1352: by using NTFS-style alternative file streams for
  the ".git" directory, it is possible to overwrite parts of the
  repository. While this has been fixed in the past for Windows,
  the same vulnerability may also exist on other systems that
  write to NTFS filesystems. We now reject any paths starting
  with ".git:" on all systems.

• CVE-2019-1353: by using NTFS-style 8.3 short names, it was
  possible to write to the ".git" directory and thus overwrite
  parts of the repository, leading to possible remote code
  execution. While this problem was already fixed in the past for
  Windows, other systems accessing NTFS filesystems are
  vulnerable to this issue too. We now enable NTFS protecions by
  default on all systems to fix this attack vector.

• CVE-2019-1354: on Windows, backslashes are not a valid part of
  a filename but are instead interpreted as directory separators.
  As other platforms allowed to use such paths, it was possible
  to write such invalid entries into a Git repository and was
  thus an attack vector to write into the ".git" dierctory. We
  now reject any entries starting with ".git" on all systems.

• CVE-2019-1387: it is possible to let a submodule's git
  directory point into a sibling's submodule directory, which may
  result in overwriting parts of the Git repository and thus lead
  to arbitrary command execution. As libgit2 doesn't provide any
  way to do submodule clones natively, it is not susceptible to
  this vulnerability. Users of libgit2 that have implemented
  recursive submodule clones manually are encouraged to review
  their implementation for this vulnerability.

Breaking API changes

• The "private" implementation details of the git_cred structure have been
  moved to a dedicated git2/sys/cred.h header, to clarify that the underlying
  structures are only provided for custom transport implementers.
  The breaking change is that the username member of the underlying struct
  is now hidden, and a new git_cred_get_username function has been provided.

Breaking CMake configuration changes

• The CMake option to use a system http-parser library, instead of the
  bundled dependency, has changed. This is due to a deficiency in
  http-parser that we have fixed in our implementation. The bundled
  library is now the default, but if you wish to force the use of the
  system http-parser implementation despite incompatibilities, you can
  specify -DUSE_HTTP_PARSER=system to CMake.

• The interactions between USE_HTTPS and SHA1_BACKEND have been
  streamlined. The detection was moved to a new USE_SHA1, modeled after
  USE_HTTPS, which takes the values "CollisionDetection/Backend/Generic", to
  better match how the "hashing backend" is selected, the default (ON) being
  "CollisionDetection". If you were using SHA1_BACKEND previously, you'll
  need to check the value you've used, or switch to the autodetection.

Authors

The following individuals provided changes that were included in this
release:

• Aaron Patterson
• Alberto Fanjul
• Anders Borum
• Augie Fackler
• Augustin Fabre
• Ayush Shridhar
• brian m. carlson
• buddyspike
• Carlos Martín Nieto
• cheese1
• Dan Skorupski
• Daniel Cohen Gindi
• Dave Lee
• David Brooks
• David Turner
• Denis Laxalde
• Dhruva Krishnamurthy
• Dominik Ritter
• Drew DeVault
• Edward Thomson
• Eric Huss
• Erik Aigner
• Etienne Samson
• Gregory Herrero
• Heiko Voigt
• Ian Hattendorf
• Jacques Germishuys
• Janardhan Pulivarthi
• Jason Haslam
• Johannes Schindelin
• Jordan Wallet
• Josh Bleecher Snyder
• kas
• kdj0c
• Laurence McGlashan
• lhchavez
• Lukas Berk
• Max Kostyukevich
• Patrick Steinhardt
• pcpthm
• Remy Suen
• Robert Coup
• romkatv
• Scott Furry
• Sebastian Henke
• Stefan Widgren
• Steve King Jr
• Sven Strickroth
• Tobias Nießen
• Tyler Ang-Wanek
• Tyler Wanek