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<title>git/refs.h, branch v2.12.2</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/git/git.git/
</subtitle>
<id>https://git.shady.money/git/atom?h=v2.12.2</id>
<link rel='self' href='https://git.shady.money/git/atom?h=v2.12.2'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/'/>
<updated>2017-01-31T18:01:24Z</updated>
<entry>
<title>refs: add option core.logAllRefUpdates = always</title>
<updated>2017-01-31T18:01:24Z</updated>
<author>
<name>Cornelius Weig</name>
<email>cornelius.weig@tngtech.com</email>
</author>
<published>2017-01-27T10:09:47Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=341fb28621201c5e6c9d3fee5baf7c532fa8a618'/>
<id>urn:sha1:341fb28621201c5e6c9d3fee5baf7c532fa8a618</id>
<content type='text'>
When core.logallrefupdates is true, we only create a new reflog for refs
that are under certain well-known hierarchies. The reason is that we
know that some hierarchies (like refs/tags) are not meant to change, and
that unknown hierarchies might not want reflogs at all (e.g., a
hypothetical refs/foo might be meant to change often and drop old
history immediately).

However, sometimes it is useful to override this decision and simply log
for all refs, because the safety and audit trail is more important than
the performance implications of keeping the log around.

This patch introduces a new "always" mode for the core.logallrefupdates
option which will log updates to everything under refs/, regardless
where in the hierarchy it is (we still will not log things like
ORIG_HEAD and FETCH_HEAD, which are known to be transient).

Based-on-patch-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Cornelius Weig &lt;cornelius.weig@tngtech.com&gt;
Reviewed-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'nd/shallow-deepen'</title>
<updated>2016-10-10T21:03:50Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2016-10-10T21:03:50Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=a460ea4a3cb1dad253604b5e2aeaa161637453a9'/>
<id>urn:sha1:a460ea4a3cb1dad253604b5e2aeaa161637453a9</id>
<content type='text'>
The existing "git fetch --depth=&lt;n&gt;" option was hard to use
correctly when making the history of an existing shallow clone
deeper.  A new option, "--deepen=&lt;n&gt;", has been added to make this
easier to use.  "git clone" also learned "--shallow-since=&lt;date&gt;"
and "--shallow-exclude=&lt;tag&gt;" options to make it easier to specify
"I am interested only in the recent N months worth of history" and
"Give me only the history since that version".

* nd/shallow-deepen: (27 commits)
  fetch, upload-pack: --deepen=N extends shallow boundary by N commits
  upload-pack: add get_reachable_list()
  upload-pack: split check_unreachable() in two, prep for get_reachable_list()
  t5500, t5539: tests for shallow depth excluding a ref
  clone: define shallow clone boundary with --shallow-exclude
  fetch: define shallow boundary with --shallow-exclude
  upload-pack: support define shallow boundary by excluding revisions
  refs: add expand_ref()
  t5500, t5539: tests for shallow depth since a specific date
  clone: define shallow clone boundary based on time with --shallow-since
  fetch: define shallow boundary with --shallow-since
  upload-pack: add deepen-since to cut shallow repos based on time
  shallow.c: implement a generic shallow boundary finder based on rev-list
  fetch-pack: use a separate flag for fetch in deepening mode
  fetch-pack.c: mark strings for translating
  fetch-pack: use a common function for verbose printing
  fetch-pack: use skip_prefix() instead of starts_with()
  upload-pack: move rev-list code out of check_non_tip()
  upload-pack: make check_non_tip() clean things up on error
  upload-pack: tighten number parsing at "deepen" lines
  ...
</content>
</entry>
<entry>
<title>Merge branch 'bc/object-id'</title>
<updated>2016-09-19T20:47:19Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2016-09-19T20:47:19Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=4af9a7d344b0e1c3b504c0cfb650dabdb1df1852'/>
<id>urn:sha1:4af9a7d344b0e1c3b504c0cfb650dabdb1df1852</id>
<content type='text'>
The "unsigned char sha1[20]" to "struct object_id" conversion
continues.  Notable changes in this round includes that ce-&gt;sha1,
i.e. the object name recorded in the cache_entry, turns into an
object_id.

It had merge conflicts with a few topics in flight (Christian's
"apply.c split", Dscho's "cat-file --filters" and Jeff Hostetler's
"status --porcelain-v2").  Extra sets of eyes double-checking for
mismerges are highly appreciated.

* bc/object-id:
  builtin/reset: convert to use struct object_id
  builtin/commit-tree: convert to struct object_id
  builtin/am: convert to struct object_id
  refs: add an update_ref_oid function.
  sha1_name: convert get_sha1_mb to struct object_id
  builtin/update-index: convert file to struct object_id
  notes: convert init_notes to use struct object_id
  builtin/rm: convert to use struct object_id
  builtin/blame: convert file to use struct object_id
  Convert read_mmblob to take struct object_id.
  notes-merge: convert struct notes_merge_pair to struct object_id
  builtin/checkout: convert some static functions to struct object_id
  streaming: make stream_blob_to_fd take struct object_id
  builtin: convert textconv_object to use struct object_id
  builtin/cat-file: convert some static functions to struct object_id
  builtin/cat-file: convert struct expand_data to use struct object_id
  builtin/log: convert some static functions to use struct object_id
  builtin/blame: convert struct origin to use struct object_id
  builtin/apply: convert static functions to struct object_id
  cache: convert struct cache_entry to use struct object_id
</content>
</entry>
<entry>
<title>Merge branch 'mh/ref-store'</title>
<updated>2016-09-19T20:47:19Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2016-09-19T20:47:19Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=4322f3848a224843a2df81055f07899ce1a1b388'/>
<id>urn:sha1:4322f3848a224843a2df81055f07899ce1a1b388</id>
<content type='text'>
The ref-store abstraction was introduced to the refs API so that we
can plug in different backends to store references.

* mh/ref-store: (38 commits)
  refs: implement iteration over only per-worktree refs
  refs: make lock generic
  refs: add method to rename refs
  refs: add methods to init refs db
  refs: make delete_refs() virtual
  refs: add method for initial ref transaction commit
  refs: add methods for reflog
  refs: add method iterator_begin
  files_ref_iterator_begin(): take a ref_store argument
  split_symref_update(): add a files_ref_store argument
  lock_ref_sha1_basic(): add a files_ref_store argument
  lock_ref_for_update(): add a files_ref_store argument
  commit_ref_update(): add a files_ref_store argument
  lock_raw_ref(): add a files_ref_store argument
  repack_without_refs(): add a files_ref_store argument
  refs: make peel_ref() virtual
  refs: make create_symref() virtual
  refs: make pack_refs() virtual
  refs: make verify_refname_available() virtual
  refs: make read_raw_ref() virtual
  ...
</content>
</entry>
<entry>
<title>refs: add methods to init refs db</title>
<updated>2016-09-09T22:28:14Z</updated>
<author>
<name>David Turner</name>
<email>dturner@twopensource.com</email>
</author>
<published>2016-09-04T16:08:41Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=6fb5acfd8f7102f53dedc887233313f233a65932'/>
<id>urn:sha1:6fb5acfd8f7102f53dedc887233313f233a65932</id>
<content type='text'>
Alternate refs backends might not need the refs/heads directory and so
on, so we make ref db initialization part of the backend.

Signed-off-by: David Turner &lt;dturner@twopensource.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
Signed-off-by: Michael Haggerty &lt;mhagger@alum.mit.edu&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>resolve_gitlink_ref(): rename path parameter to submodule</title>
<updated>2016-09-09T22:28:13Z</updated>
<author>
<name>Michael Haggerty</name>
<email>mhagger@alum.mit.edu</email>
</author>
<published>2016-09-04T16:08:24Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=a8355bb717aaf2d5d9b3781aa78402d0053fa87a'/>
<id>urn:sha1:a8355bb717aaf2d5d9b3781aa78402d0053fa87a</id>
<content type='text'>
Signed-off-by: Michael Haggerty &lt;mhagger@alum.mit.edu&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>refs: add a backend method structure</title>
<updated>2016-09-09T22:28:12Z</updated>
<author>
<name>Ronnie Sahlberg</name>
<email>sahlberg@google.com</email>
</author>
<published>2016-09-04T16:08:10Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=3dce444f178503bf3da13ade6f79c80d6964d175'/>
<id>urn:sha1:3dce444f178503bf3da13ade6f79c80d6964d175</id>
<content type='text'>
Add a `struct ref_storage_be` to represent types of reference stores. In
OO notation, this is the class, and will soon hold some class
methods (e.g., a factory to create new ref_store instances) and will
also serve as the vtable for ref_store instances of that type.

As yet, the backends cannot do anything.

Signed-off-by: Ronnie Sahlberg &lt;sahlberg@google.com&gt;
Signed-off-by: David Turner &lt;dturner@twopensource.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Michael Haggerty &lt;mhagger@alum.mit.edu&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>refs: add an update_ref_oid function.</title>
<updated>2016-09-07T19:59:43Z</updated>
<author>
<name>brian m. carlson</name>
<email>sandals@crustytoothpaste.net</email>
</author>
<published>2016-09-05T20:08:08Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=8f6dc7e32eee2944d1490ff9bf12ec329f3b33c2'/>
<id>urn:sha1:8f6dc7e32eee2944d1490ff9bf12ec329f3b33c2</id>
<content type='text'>
Several places around the codebase want to pass update_ref data from
struct object_id, but update_ref may also be passed NULL pointers.
Instead of checking and dereferencing in every caller, create an
update_ref_oid which wraps update_ref and provides this functionality.

Signed-off-by: brian m. carlson &lt;sandals@crustytoothpaste.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'mh/ref-iterators'</title>
<updated>2016-07-25T21:13:33Z</updated>
<author>
<name>Junio C Hamano</name>
<email>gitster@pobox.com</email>
</author>
<published>2016-07-25T21:13:33Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=87492cb24d9d8be8e18217b89ae5f090089ff31d'/>
<id>urn:sha1:87492cb24d9d8be8e18217b89ae5f090089ff31d</id>
<content type='text'>
The API to iterate over all the refs (i.e. for_each_ref(), etc.)
has been revamped.

* mh/ref-iterators:
  for_each_reflog(): reimplement using iterators
  dir_iterator: new API for iterating over a directory tree
  for_each_reflog(): don't abort for bad references
  do_for_each_ref(): reimplement using reference iteration
  refs: introduce an iterator interface
  ref_resolves_to_object(): new function
  entry_resolves_to_object(): rename function from ref_resolves_to_object()
  get_ref_cache(): only create an instance if there is a submodule
  remote rm: handle symbolic refs correctly
  delete_refs(): add a flags argument
  refs: use name "prefix" consistently
  do_for_each_ref(): move docstring to the header file
  refs: remove unnecessary "extern" keywords
</content>
</entry>
<entry>
<title>refs: introduce an iterator interface</title>
<updated>2016-06-20T18:38:20Z</updated>
<author>
<name>Michael Haggerty</name>
<email>mhagger@alum.mit.edu</email>
</author>
<published>2016-06-18T04:15:15Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/git/commit/?id=3bc581b9406e1e9a3f879d379106ee1e3bc48f5c'/>
<id>urn:sha1:3bc581b9406e1e9a3f879d379106ee1e3bc48f5c</id>
<content type='text'>
Currently, the API for iterating over references is via a family of
for_each_ref()-type functions that invoke a callback function for each
selected reference. All of these eventually call do_for_each_ref(),
which knows how to do one thing: iterate in parallel through two
ref_caches, one for loose and one for packed refs, giving loose
references precedence over packed refs. This is rather complicated code,
and is quite specialized to the files backend. It also requires callers
to encapsulate their work into a callback function, which often means
that they have to define and use a "cb_data" struct to manage their
context.

The current design is already bursting at the seams, and will become
even more awkward in the upcoming world of multiple reference storage
backends:

* Per-worktree vs. shared references are currently handled via a kludge
  in git_path() rather than iterating over each part of the reference
  namespace separately and merging the results. This kludge will cease
  to work when we have multiple reference storage backends.

* The current scheme is inflexible. What if we sometimes want to bypass
  the ref_cache, or use it only for packed or only for loose refs? What
  if we want to store symbolic refs in one type of storage backend and
  non-symbolic ones in another?

In the future, each reference backend will need to define its own way of
iterating over references. The crux of the problem with the current
design is that it is impossible to compose for_each_ref()-style
iterations, because the flow of control is owned by the for_each_ref()
function. There is nothing that a caller can do but iterate through all
references in a single burst, so there is no way for it to interleave
references from multiple backends and present the result to the rest of
the world as a single compound backend.

This commit introduces a new iteration primitive for references: a
ref_iterator. A ref_iterator is a polymorphic object that a reference
storage backend can be asked to instantiate. There are three functions
that can be applied to a ref_iterator:

* ref_iterator_advance(): move to the next reference in the iteration
* ref_iterator_abort(): end the iteration before it is exhausted
* ref_iterator_peel(): peel the reference currently being looked at

Iterating using a ref_iterator leaves the flow of control in the hands
of the caller, which means that ref_iterators from multiple
sources (e.g., loose and packed refs) can be composed and presented to
the world as a single compound ref_iterator.

It also means that the backend code for implementing reference iteration
will sometimes be more complicated. For example, the
cache_ref_iterator (which iterates over a ref_cache) can't use the C
stack to recurse; instead, it must manage its own stack internally as
explicit data structures. There is also a lot of boilerplate connected
with object-oriented programming in C.

Eventually, end-user callers will be able to be written in a more
natural way—managing their own flow of control rather than having to
work via callbacks. Since there will only be a few reference backends
but there are many consumers of this API, this is a good tradeoff.

More importantly, we gain composability, and especially the possibility
of writing interchangeable parts that can work with any ref_iterator.

For example, merge_ref_iterator implements a generic way of merging the
contents of any two ref_iterators. It is used to merge loose + packed
refs as part of the implementation of the files_ref_iterator. But it
will also be possible to use it to merge other pairs of reference
sources (e.g., per-worktree vs. shared refs).

Another example is prefix_ref_iterator, which can be used to trim a
prefix off the front of reference names before presenting them to the
caller (e.g., "refs/heads/master" -&gt; "master").

In this patch, we introduce the iterator abstraction and many utilities,
and implement a reference iterator for the files ref storage backend.
(I've written several other obvious utilities, for example a generic way
to filter references being iterated over. These will probably be useful
in the future. But they are not needed for this patch series, so I am
not including them at this time.)

In a moment we will rewrite do_for_each_ref() to work via reference
iterators (allowing some special-purpose code to be discarded), and do
something similar for reflogs. In future patch series, we will expose
the ref_iterator abstraction in the public refs API so that callers can
use it directly.

Implementation note: I tried abstracting this a layer further to allow
generic iterators (over arbitrary types of objects) and generic
utilities like a generic merge_iterator. But the implementation in C was
very cumbersome, involving (in my opinion) too much boilerplate and too
much unsafe casting, some of which would have had to be done on the
caller side. However, I did put a few iterator-related constants in a
top-level header file, iterator.h, as they will be useful in a moment to
implement iteration over directory trees and possibly other types of
iterators in the future.

Signed-off-by: Ramsay Jones &lt;ramsay@ramsayjones.plus.com&gt;
Signed-off-by: Michael Haggerty &lt;mhagger@alum.mit.edu&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
</content>
</entry>
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