Update repack_without_refs to take an err argument and update it if there
is a failure. Pass the err variable from ref_transaction_commit to this
function so that callers can print a meaningful error message if _commit
fails due to this function.
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

Making errno when returning from lock_file() meaningful, which should
fix

 * an existing almost-bug in lock_ref_sha1_basic where it assumes
   errno==ENOENT is meaningful and could waste some work on retries

 * an existing bug in repack_without_refs where it prints
   strerror(errno) and picks advice based on errno, despite errno
   potentially being zero and potentially having been clobbered by
   that point
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

Add a strbuf argument to _commit so that we can pass an error string back to
the caller. So that we can do error logging from the caller instead of from
_commit.

Longer term plan is to first convert all callers to use onerr==QUIET_ON_ERR
and craft any log messages from the callers themselves and finally remove the
onerr argument completely.
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

ref_transaction_create|delete|update has no need to modify the sha1
arguments passed to it so it should use const unsigned char* instead
of unsigned char*.

Some functions, such as fast_forward_to(), already have its old/new
sha1 arguments as consts. This function will at some point need to
use ref_transaction_update() in which case this change is required.
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

We do not yet need both a rollback and a free function for transactions.
Remove ref_transaction_rollback and use ref_transaction_free instead.

At a later stage we may reintroduce a rollback function if we want to start
adding reusable transactions and similar.
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>

When 'git remote prune' was used to delete many refs in a repository
with many refs, a lot of time was spent checking for (now) dangling
symbolic refs pointing to the deleted ref, since warn_dangling_symref()
was once per deleted ref to check all other refs in the repository.

Avoid this using the new warn_dangling_symrefs() function which
makes one pass over all refs and checks for all the deleted refs in
one go, after they have all been deleted.
Signed-off-by: NJens Lindström <jl@opera.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When 'git remote rm' or 'git remote prune' were used in a repository
with many refs, and needed to delete many remote-tracking refs, a lot
of time was spent deleting those refs since for each deleted ref,
repack_without_refs() was called to rewrite packed-refs without just
that deleted ref.

To avoid this, call repack_without_refs() first to repack without all
the refs that will be deleted, before calling delete_ref() to delete
each one completely.  The call to repack_without_ref() in delete_ref()
then becomes a no-op, since packed-refs already won't contain any of
the deleted refs.
Signed-off-by: NJens Lindström <jl@opera.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add two new functions, reflog_exists and delete_reflog, to hide the internal
reflog implementation (that they are files under .git/logs/...) from callers.
Update checkout.c to use these functions in update_refs_for_switch instead of
building pathnames and calling out to file access functions. Update reflog.c
to use these to check if the reflog exists. Now there are still many places
in reflog.c where we are still leaking the reflog storage implementation but
this at least reduces the number of such dependencies by one. Finally
change two places in refs.c itself to use the new function to check if a ref
exists or not isntead of build-path-and-stat(). Now, this is strictly not all
that important since these are in parts of refs that are implementing the
actual file storage backend but on the other hand it will not hurt either.
Signed-off-by: NRonnie Sahlberg <sahlberg@google.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is consistent with the usual nomenclature.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It has been superseded by reference transactions.  This also means
that struct ref_update can become private.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Build out the API for dealing with a bunch of reference checks and
changes within a transaction.  Define an opaque ref_transaction type
that is managed entirely within refs.c.  Introduce functions for
beginning a transaction, adding updates to a transaction, and
committing/rolling back a transaction.

This API will soon replace update_refs().
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The old signature of update_refs() required a
(const struct ref_update **) for its updates_orig argument.  The
"const" is presumably there to promise that the function will not
modify the contents of the structures.

But this declaration does not permit the function to be called with a
(struct ref_update **), which is perfectly legitimate.  C's type
system is not powerful enough to express what we'd like.  So remove
the first "const" from the declaration.

On the other hand, the function *can* promise not to modify the
pointers within the array that is passed to it without inconveniencing
its callers.  So add a "const" that has that effect, making the final
declaration
(struct ref_update * const *).
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Given that these constants are only being used when updating
references, it is inappropriate to give them such generic names as
"DIE_ON_ERR".  So prefix their names with "UPDATE_REFS_".
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The function 'invalidate_ref_cache' was introduced in 79c7ca54 (2011-10-17,
invalidate_ref_cache(): rename function from invalidate_cached_refs())
by a rename and elevated to be publicly usable in 8be8bde7 (2011-10-17,
invalidate_ref_cache(): expose this function in the refs API)

However it is not used anymore, as 8bf90dc9 (2011-10-17, write_ref_sha1():
only invalidate the loose ref cache) and (much) later 506a760d (2013-04-22,
refs: change how packed refs are deleted) removed any calls to this
function. So it seems as if we don't need that function any more,
good bye!
Signed-off-by: NStefan Beller <stefanbeller@googlemail.com>
Acked-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add 'struct ref_update' to encode the information needed to update or
delete a ref (name, new sha1, optional old sha1, no-deref flag).  Add
function 'update_refs' accepting an array of updates to perform.  First
sort the input array to order locks consistently everywhere and reject
multiple updates to the same ref.  Then acquire locks on all refs with
verified old values.  Then update or delete all refs accordingly.  Fail
if any one lock cannot be obtained or any one old value does not match.

Though the refs themselves cannot be modified together in a single
atomic transaction, this function does enable some useful semantics.
For example, a caller may create a new branch starting from the head of
another branch and rewind the original branch at the same time.  This
transfers ownership of commits between branches without risk of losing
commits added to the original branch by a concurrent process, or risk of
a concurrent process creating the new branch first.
Signed-off-by: NBrad King <brad.king@kitware.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Expose lock_ref_sha1_basic's type_p argument to callers of
lock_any_ref_for_update.  Update all call sites to ignore it by passing
NULL for now.
Signed-off-by: NBrad King <brad.king@kitware.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Handle simple transactions for the packed-refs file at the
packed_ref_cache level via new functions lock_packed_refs(),
commit_packed_refs(), and rollback_packed_refs().

Only allow the packed ref cache to be modified (via add_packed_ref())
while the packed refs file is locked.

Change clone to add the new references within a transaction.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The lifetime of the memory pointed to by the refname and sha1
arguments to each_ref_fn was never documented, but some callers used
to assume that it was essentially permanent.  In fact the API does
*not* guarantee that these objects live beyond a single callback
invocation.

In the current code, the lifetimes are bound together with the
lifetimes of the ref_caches.  Since these are usually long, the
callers usually got away with their sloppiness.  But even today, if a
ref_cache is invalidated the memory can be freed.  And planned changes
to reference caching, needed to eliminate race conditions, will
probably need to shorten the lifetimes of these objects.

The commits leading up to this have (hopefully) fixed all of the
callers of the for_each_ref()-like functions.  This commit does the
last step: documents what each_ref_fn callbacks can assume about
object lifetimes.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

pack-refs.c doesn't contain much code, and the code it does contain is
closely related to reference handling.  Moreover, there is some
duplication between pack_refs() and repack_without_ref().  Therefore,
merge pack-refs.c into refs.c and pack-refs.h into refs.h.

The code duplication will be addressed in future commits.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The old version was inconsistent: when a reference was
REF_KNOWS_PEELED but with a null peeled value, it returned non-zero
for the current reference but zero for other references.  Change the
behavior for non-current references to match that of current_ref,
which is what callers expect.  Document the behavior.

Current callers only call peel_ref() from within a for_each_ref-style
iteration and only for the current ref; therefore, the buggy code path
was never reached.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Document the bits that can appear in the "flags" parameter passed to
an each_ref_function and/or in the ref_entry::flag field.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git checkout -" is a short-hand for "git checkout @{-1}" and the
"@{nth}" notation for a negative number is to find nth previous
checkout in the reflog of the HEAD to determine the name of the
branch the user was on.  We would want to find the nth most recent
reflog entry that matches "checkout: moving from X to Y" for this.

Unfortunately, reflog is implemented as an append-only file, and the
API to iterate over its entries, for_each_reflog_ent(), reads the
file in order, giving the entries from the oldest to newer.  For the
purpose of finding nth most recent one, this API forces us to record
the last n entries in a rotating buffer and give the result out only
after we read everything.  To optimize for a common case of finding
the nth most recent one for a small value of n, we also have a side
API for_each_recent_reflog_ent() that starts reading near the end of
the file, but it still has to read the entries in the "wrong" order.
The implementation of understanding @{-1} uses this interface.

This all becomes unnecessary if we add an API to let us iterate over
reflog entries in the reverse order, from the newest to older.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

A repository may have refs that are only used for its internal
bookkeeping purposes that should not be exposed to the others that
come over the network.

Teach upload-pack to omit some refs from its initial advertisement
by paying attention to the uploadpack.hiderefs multi-valued
configuration variable.  Do the same to receive-pack via the
receive.hiderefs variable.  As a convenient short-hand, allow using
transfer.hiderefs to set the value to both of these variables.

Any ref that is under the hierarchies listed on the value of these
variable is excluded from responses to requests made by "ls-remote",
"fetch", etc. (for upload-pack) and "push" (for receive-pack).

Because these hidden refs do not count as OUR_REF, an attempt to
fetch objects at the tip of them will be rejected, and because these
refs do not get advertised, "git push :" will not see local branches
that have the same name as them as "matching" ones to be sent.

An attempt to update/delete these hidden refs with an explicit
refspec, e.g. "git push origin :refs/hidden/22", is rejected.  This
is not a new restriction.  To the pusher, it would appear that there
is no such ref, so its push request will conclude with "Now that I
sent you all the data, it is time for you to update the refs.  I saw
that the ref did not exist when I started pushing, and I want the
result to point at this commit".  The receiving end will apply the
compare-and-swap rule to this request and rejects the push with
"Well, your update request conflicts with somebody else; I see there
is such a ref.", which is the right thing to do. Otherwise a push to
a hidden ref will always be "the last one wins", which is not a good
default.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Store references hierarchically in a tree that matches the
pseudo-directory structure of the reference names.  Add a new kind of
ref_entry (with flag REF_DIR) to represent a whole subdirectory of
references.  Sort ref_dirs one subdirectory at a time.

NOTE: the dirs can now be sorted as a side-effect of other function
calls.  Therefore, it would be problematic to do something from a
each_ref_fn callback that could provoke the sorting of a directory
that is currently being iterated over (i.e., the directory containing
the entry that is being processed or any of its parents).

This is a bit far-fetched, because a directory is always sorted just
before being iterated over.  Therefore, read-only accesses cannot
trigger the sorting of a directory whose iteration has already
started.  But if a callback function would add a reference to a parent
directory of the reference in the iteration, then try to resolve a
reference under that directory, a re-sort could be triggered and cause
the iteration to work incorrectly.

Nevertheless...add a comment in refs.h warning against modifications
during iteration.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The extra_refs provided a kludgy way to create fake references at a
global level in the hope that they would only affect some particular
code path.  The last user of this API been rewritten, so strip this
stuff out before somebody else gets the bad idea of using it.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add a new function add_packed_ref() that adds a reference directly to
the in-memory packed reference cache.  This will be useful for
creating local references while cloning.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Try consistently to use the name "sha1" for parameters to which a SHA1
will be stored.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Try to consistently use the variable name "refname" when referring to
a string that names a reference.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Instead of keeping this as an internal API, let the callers find
out the reason why resolve_ref() returned NULL is not because there
was no such file in $GIT_DIR but because a file was corrupt.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Make invalidate_ref_cache() an official part of the refs API.  It is
currently a fact of life that code outside of refs.c mucks about with
references.  This change gives such code a way of informing the refs
module that it should no longer trust its cache.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In add_ref(), verify that the refname is formatted correctly before
adding it to the ref_list.  Here we have to allow refname components
that start with ".", since (for example) the remote protocol uses
synthetic reference name ".have".  So add a new REFNAME_DOT_COMPONENT
flag that can be passed to check_refname_format() to allow leading
dots.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since much of the infrastructure does not work correctly with
unnormalized refnames, change check_refname_format() to reject them.

Similarly, change "git check-ref-format" to reject unnormalized
refnames by default.  But add an option --normalize, which causes "git
check-ref-format" to normalize the refname before checking its format,
and print the normalized refname.  This is exactly the behavior of the
old --print option, which is retained but deprecated.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Change check_ref_format() to take a flags argument that indicates what
is acceptable in the reference name (analogous to "git
check-ref-format"'s "--allow-onelevel" and "--refspec-pattern").  This
is more convenient for callers and also fixes a failure in the test
suite (and likely elsewhere in the code) by enabling "onelevel" and
"refspec-pattern" to be allowed independently of each other.

Also rename check_ref_format() to check_refname_format() to make it
obvious that it deals with refnames rather than references themselves.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When a push specifies deletion of non-existent refs, the post post-receive and
post-update hooks receive them as input/arguments.

For instance, for the following push, where refs/heads/nonexistent is a ref
which does not exist on the remote side:

	git push origin :refs/heads/nonexistent

the post-receive hook receives from standard input:

	<null-sha1> SP <null-sha1> SP refs/heads/nonexistent

and the post-update hook receives as arguments:

	refs/heads/nonexistent

which does not make sense since it is a no-op.

Teach receive-pack not to pass non-existent refs to the post-receive and
post-update hooks. If the push only attempts to delete non-existent refs,
these hooks are not even called.

The update and pre-receive hooks are still notified about attempted
deletion of non-existent refs to give them a chance to inspect the
situation and act on it.

[jc: mild fix-ups to avoid introducing an extra list; also added fixes to
some tests]
Signed-off-by: NPang Yan Han <pangyanhan@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add support for dividing the refs of a single repository into multiple
namespaces, each of which can have its own branches, tags, and HEAD.
Git can expose each namespace as an independent repository to pull from
and push to, while sharing the object store, and exposing all the refs
to operations such as git-gc.

Storing multiple repositories as namespaces of a single repository
avoids storing duplicate copies of the same objects, such as when
storing multiple branches of the same source.  The alternates mechanism
provides similar support for avoiding duplicates, but alternates do not
prevent duplication between new objects added to the repositories
without ongoing maintenance, while namespaces do.

To specify a namespace, set the GIT_NAMESPACE environment variable to
the namespace.  For each ref namespace, git stores the corresponding
refs in a directory under refs/namespaces/.  For example,
GIT_NAMESPACE=foo will store refs under refs/namespaces/foo/.  You can
also specify namespaces via the --namespace option to git.

Note that namespaces which include a / will expand to a hierarchy of
namespaces; for example, GIT_NAMESPACE=foo/bar will store refs under
refs/namespaces/foo/refs/namespaces/bar/.  This makes paths in
GIT_NAMESPACE behave hierarchically, so that cloning with
GIT_NAMESPACE=foo/bar produces the same result as cloning with
GIT_NAMESPACE=foo and cloning from that repo with GIT_NAMESPACE=bar.  It
also avoids ambiguity with strange namespace paths such as
foo/refs/heads/, which could otherwise generate directory/file conflicts
within the refs directory.

Add the infrastructure for ref namespaces: handle the GIT_NAMESPACE
environment variable and --namespace option, and support iterating over
refs in a namespace.
Signed-off-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NJamey Sharp <jamey@minilop.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When create a new branch, we fed "refs/heads/<proposed name>" as a string
to get_sha1() and expected it to fail when a branch already exists.

The right way to check if a ref exists is to check with resolve_ref().

A naïve solution that might appear attractive but does not work is to
forbid slashes in get_describe_name() but that will not work. A describe
name is is in the form of "ANYTHING-g<short sha1>", and that ANYTHING part
comes from a original tag name used in the repository the user ran the
describe command. A sick user could have a confusing hierarchical tag
whose name is "refs/heads/foobar" (stored as refs/tags/refs/heads/foobar")
to generate a describe name "refs/heads/foobar-6-g02ac9837", and we should
be able to use that name to refer to the object whose name is 02ac9837.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

By passing the path to a submodule in opt->submodule, the function can
be used to walk history in the named submodule repository, instead of
the toplevel repository.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

859c3017 (refs: split log_ref_write logic into log_ref_setup,
2010-05-21) refactors the stack allocation of the log_file array into
the new log_ref_setup() function, but passes it back to the caller.

Since the original intent seems to have been to split the work between
log_ref_setup and log_ref_write, make it the caller's responsibility
to allocate the buffer.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Reported-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>