Our convention is for error messages to start with a lower-case
letter.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of writing error messages directly to stderr, write them to
a "strbuf *err". The caller, lock_ref_sha1_basic(), uses this error
reporting convention with all the other callees, and reports its
error this way to its callers.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The caller already knows how to do it, so always do it in the same
place.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Its return value wasn't conveying any extra information, but it made
the reader wonder whether the ref_lock that it returned might be
different than the one that was passed to it. So change the function
to the traditional "return 0 on success or a negative value on error".
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the callers of the for_each_ref family of functions have now
been rewritten to work with object_ids, so this adapter is no longer
needed.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change typedef each_ref_fn to take a "const struct object_id *oid"
parameter instead of "const unsigned char *sha1".
To aid this transition, implement an adapter that can be used to wrap
old-style functions matching the old typedef, which is now called
"each_ref_sha1_fn"), and make such functions callable via the new
interface. This requires the old function and its cb_data to be
wrapped in a "struct each_ref_fn_sha1_adapter", and that object to be
used as the cb_data for an adapter function, each_ref_fn_adapter().
This is an enormous diff, but most of it consists of simple,
mechanical changes to the sites that call any of the "for_each_ref"
family of functions. Subsequent to this change, the call sites can be
rewritten one by one to use the new interface.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of dying immediately upon failing to obtain a lock, retry
after a short while with backoff.
* mh/lockfile-retry:
lock_packed_refs(): allow retries when acquiring the packed-refs lock
lockfile: allow file locking to be retried with a timeout
The ref API did not handle cases where 'refs/heads/xyzzy/frotz' is
removed at the same time as 'refs/heads/xyzzy' is added (or vice
versa) very well.
* mh/ref-directory-file:
reflog_expire(): integrate lock_ref_sha1_basic() errors into ours
ref_transaction_commit(): delete extra "the" from error message
ref_transaction_commit(): provide better error messages
rename_ref(): integrate lock_ref_sha1_basic() errors into ours
lock_ref_sha1_basic(): improve diagnostics for ref D/F conflicts
lock_ref_sha1_basic(): report errors via a "struct strbuf *err"
verify_refname_available(): report errors via a "struct strbuf *err"
verify_refname_available(): rename function
refs: check for D/F conflicts among refs created in a transaction
ref_transaction_commit(): use a string_list for detecting duplicates
is_refname_available(): use dirname in first loop
struct nonmatching_ref_data: store a refname instead of a ref_entry
report_refname_conflict(): inline function
entry_matches(): inline function
is_refname_available(): convert local variable "dirname" to strbuf
is_refname_available(): avoid shadowing "dir" variable
is_refname_available(): revamp the comments
t1404: new tests of ref D/F conflicts within transactions
Multi-ref transaction support we merged a few releases ago
unnecessarily kept many file descriptors open, risking to fail with
resource exhaustion. This is for 2.4.x track.
* mh/write-refs-sooner-2.4:
ref_transaction_commit(): fix atomicity and avoid fd exhaustion
ref_transaction_commit(): remove the local flags variable
ref_transaction_commit(): inline call to write_ref_sha1()
rename_ref(): inline calls to write_ref_sha1() from this function
commit_ref_update(): new function, extracted from write_ref_sha1()
write_ref_to_lockfile(): new function, extracted from write_ref_sha1()
t7004: rename ULIMIT test prerequisite to ULIMIT_STACK_SIZE
update-ref: test handling large transactions properly
ref_transaction_commit(): fix atomicity and avoid fd exhaustion
ref_transaction_commit(): remove the local flags variable
ref_transaction_commit(): inline call to write_ref_sha1()
rename_ref(): inline calls to write_ref_sha1() from this function
commit_ref_update(): new function, extracted from write_ref_sha1()
write_ref_to_lockfile(): new function, extracted from write_ref_sha1()
t7004: rename ULIMIT test prerequisite to ULIMIT_STACK_SIZE
update-ref: test handling large transactions properly
The refs API uses ref_lock struct which had its own "int fd", even
though the same file descriptor was in the lock struct it contains.
Clean-up the code to lose this redundant field.
* sb/ref-lock-lose-lock-fd:
refs.c: remove lock_fd from struct ref_lock
Currently, there is only one attempt to acquire any lockfile, and if
the lock is held by another process, the locking attempt fails
immediately.
This is not such a limitation for loose reference files. First, they
don't take long to rewrite. Second, most reference updates have a
known "old" value, so if another process is updating a reference at
the same moment that we are trying to lock it, then probably the
expected "old" value will not longer be valid, and the update will
fail anyway.
But these arguments do not hold for packed-refs:
* The packed-refs file can be large and take significant time to
rewrite.
* Many references are stored in a single packed-refs file, so it could
be that the other process was changing a different reference than
the one that we are interested in.
Therefore, it is much more likely for there to be spurious lock
conflicts in connection to the packed-refs file, resulting in
unnecessary command failures.
So, if the first attempt to lock the packed-refs file fails, continue
retrying for a configurable length of time before giving up. The
default timeout is 1 second.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The old code was roughly
for update in updates:
acquire locks and check old_sha
for update in updates:
if changing value:
write_ref_to_lockfile()
commit_ref_update()
for update in updates:
if deleting value:
unlink()
rewrite packed-refs file
for update in updates:
if reference still locked:
unlock_ref()
This has two problems.
Non-atomic updates
==================
The atomicity of the reference transaction depends on all pre-checks
being done in the first loop, before any changes have started being
committed in the second loop. The problem is that
write_ref_to_lockfile() (previously part of write_ref_sha1()), which
is called from the second loop, contains two more checks:
* It verifies that new_sha1 is a valid object
* If the reference being updated is a branch, it verifies that
new_sha1 points at a commit object (as opposed to a tag, tree, or
blob).
If either of these checks fails, the "transaction" is aborted during
the second loop. But this might happen after some reference updates
have already been permanently committed. In other words, the
all-or-nothing promise of "git update-ref --stdin" could be violated.
So these checks have to be moved to the first loop.
File descriptor exhaustion
==========================
The old code locked all of the references in the first loop, leaving
all of the lockfiles open until later loops. Since we might be
updating a lot of references, this could result in file descriptor
exhaustion.
The solution
============
After this patch, the code looks like
for update in updates:
acquire locks and check old_sha
if changing value:
write_ref_to_lockfile()
else:
close_ref()
for update in updates:
if changing value:
commit_ref_update()
for update in updates:
if deleting value:
unlink()
rewrite packed-refs file
for update in updates:
if reference still locked:
unlock_ref()
This fixes both problems:
1. The pre-checks in write_ref_to_lockfile() are now done in the first
loop, before any changes have been committed. If any of the checks
fails, the whole transaction can now be rolled back correctly.
2. All lockfiles are closed in the first loop immediately after they
are created (either by write_ref_to_lockfile() or by close_ref()).
This means that there is never more than one open lockfile at a
time, preventing file descriptor exhaustion.
To simplify the bookkeeping across loops, add a new REF_NEEDS_COMMIT
bit to update->flags, which keeps track of whether the corresponding
lockfile needs to be committed, as opposed to just unlocked. (Since
"struct ref_update" is internal to the refs module, this change is not
visible to external callers.)
This change fixes two tests in t1400.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, work directly with update->flags. This has the advantage that
the REF_DELETING bit, set in the first loop, can be read in the second
loop instead of having to be recomputed. Plus, it was potentially
confusing having both update->flags and flags, which sometimes had
different values.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
That was the last caller, so delete function write_ref_sha1().
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of what it does is unneeded from these call sites.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is the first step towards separating the checking and writing of
the new reference value to committing the change.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An earlier rewrite to use strbuf_getwholeline() instead of fgets(3)
to read packed-refs file revealed that the former is unacceptably
inefficient.
* jk/reading-packed-refs:
t1430: add another refs-escape test
read_packed_refs: avoid double-checking sane refs
strbuf_getwholeline: use getdelim if it is available
strbuf_getwholeline: avoid calling strbuf_grow
strbuf_addch: avoid calling strbuf_grow
config: use getc_unlocked when reading from file
strbuf_getwholeline: use getc_unlocked
git-compat-util: add fallbacks for unlocked stdio
strbuf_getwholeline: use getc macro
A replacement for contrib/workdir/git-new-workdir that does not
rely on symbolic links and make sharing of objects and refs safer
by making the borrowee and borrowers aware of each other.
* nd/multiple-work-trees: (41 commits)
prune --worktrees: fix expire vs worktree existence condition
t1501: fix test with split index
t2026: fix broken &&-chain
t2026 needs procondition SANITY
git-checkout.txt: a note about multiple checkout support for submodules
checkout: add --ignore-other-wortrees
checkout: pass whole struct to parse_branchname_arg instead of individual flags
git-common-dir: make "modules/" per-working-directory directory
checkout: do not fail if target is an empty directory
t2025: add a test to make sure grafts is working from a linked checkout
checkout: don't require a work tree when checking out into a new one
git_path(): keep "info/sparse-checkout" per work-tree
count-objects: report unused files in $GIT_DIR/worktrees/...
gc: support prune --worktrees
gc: factor out gc.pruneexpire parsing code
gc: style change -- no SP before closing parenthesis
checkout: clean up half-prepared directories in --to mode
checkout: reject if the branch is already checked out elsewhere
prune: strategies for linked checkouts
checkout: support checking out into a new working directory
...
Now that lock_ref_sha1_basic() gives us back its error messages via a
strbuf, incorporate its error message into our error message rather
than emitting two separate error messages.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
While we are in the area, let's remove a superfluous definite article
from the error message that is emitted when the reference cannot be
locked. This improves how it reads and makes it a bit shorter.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Now that lock_ref_sha1_basic() gives us back its error messages via a
strbuf, incorporate its error message into our error message rather
than emitting one error messages to stderr immediately and returning a
second to our caller.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Now that lock_ref_sha1_basic() gives us back its error messages via a
strbuf, incorporate its error message into our error message rather
than emitting two separate error messages.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
If there is a failure to lock a reference that is likely caused by a
D/F conflict (e.g., trying to lock "refs/foo/bar" when reference
"refs/foo" already exists), invoke verify_refname_available() to try
to generate a more helpful error message.
That function might not detect an error. For example, some
non-reference file might be blocking the deletion of an
otherwise-empty directory tree, or there might be a race with another
process that just deleted the offending reference. In such cases,
generate the strerror-based error message like before.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
For now, change the callers to spew the error to stderr like before.
But soon we will change them to incorporate the reason for the failure
into their own error messages.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
It shouldn't be spewing errors directly to stderr.
For now, change its callers to spew the errors to stderr.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Rename is_refname_available() to verify_refname_available() and change
its return value from 1 for success to 0 for success, to be consistent
with our error-handling convention. In a moment it will also get a
"struct strbuf *err" parameter.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
If two references that D/F conflict (e.g., "refs/foo" and
"refs/foo/bar") are created in a single transaction, the old code
discovered the problem only after the "commit" phase of
ref_transaction_commit() had already begun. This could leave some
references updated and others not, which violates the promise of
atomicity.
Instead, check for such conflicts during the "locking" phase:
* Teach is_refname_available() to take an "extras" parameter that can
contain extra reference names with which the specified refname must
not conflict.
* Change lock_ref_sha1_basic() to take an "extras" parameter, which it
passes through to is_refname_available().
* Change ref_transaction_commit() to pass "affected_refnames" to
lock_ref_sha1_basic() as its "extras" argument.
This change fixes a test case in t1404.
This code is a bit stricter than it needs to be. We could conceivably
allow reference "refs/foo/bar" to be created in the same transaction
as "refs/foo" is deleted (or vice versa). But that would be
complicated to implement, because it is not possible to lock
"refs/foo/bar" while "refs/foo" exists as a loose reference, but on
the other hand we don't want to delete some references before adding
others (because that could leave a gap during which required objects
are unreachable). There is also a complication that reflog files'
paths can conflict.
Any less-strict implementation would probably require tricks like the
packing of all references before the start of the real transaction, or
the use of temporary intermediate reference names.
So for now let's accept too-strict checks. Some reference update
transactions will be rejected unnecessarily, but they will be rejected
in their entirety rather than leaving the repository in an
intermediate state, as would happen now.
Please note that there is still one kind of D/F conflict that is *not*
handled correctly. If two processes are running at the same time, and
one tries to create "refs/foo" at the same time that the other tries
to create "refs/foo/bar", then they can race with each other. Both
processes can obtain their respective locks ("refs/foo.lock" and
"refs/foo/bar.lock"), proceed to the "commit" phase of
ref_transaction_commit(), and then the slower process will discover
that it cannot rename its lockfile into place (after possibly having
committed changes to other references). There appears to be no way to
fix this race without changing the locking policy, which in turn would
require a change to *all* Git clients.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Detect duplicates by storing the reference names in a string_list and
sorting that, instead of sorting the ref_updates directly.
* In a moment the string_list will be used for another purpose, too.
* This removes the need for the custom comparison function
ref_update_compare().
* This means that we can carry out the updates in the order that the
user specified them instead of reordering them. This might be handy
someday if, we want to permit multiple updates to a single reference
as long as they are compatible with each other.
Note: we can't use string_list_remove_duplicates() to check for
duplicates, because we need to know the name of the reference that
appeared multiple times, to be used in the error message.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
In the first loop (over prefixes of refname), use dirname to keep
track of the current prefix. This is not an improvement in itself, but
in a moment we will start using dirname for a role where a
NUL-terminated string is needed.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Now that we don't need a ref_entry to pass to
report_refname_conflict(), it is sufficient to store the refname of
the conflicting reference.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
It wasn't pulling its weight. And we are about to need code similar to
this where no ref_entry is available and with more diverse error
messages. Rather than try to generalize the function, just inline it.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
It wasn't pulling its weight. And in a moment we will need similar
tests that take a refname rather than a ref_entry as parameter, which
would have made entry_matches() even less useful.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
This change wouldn't be worth it by itself, but in a moment we will
use the strbuf for more string juggling.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
The function had a "dir" parameter that was shadowed by a local "dir"
variable within a code block. Use the former in place of the latter.
(This is consistent with "dir"'s use elsewhere in the function.)
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Change the comments to a running example of running the function with
refname set to "refs/foo/bar". Add some more explanation of the logic.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
The 'lock_fd' is the same as 'lk->fd'. No need to store it twice so remove
it.
No functional changes intended.
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Prior to d0f810f (refs.c: allow listing and deleting badly
named refs, 2014-09-03), read_packed_refs would barf on any
malformed refnames by virtue of calling create_ref_entry
with the "check" parameter set to 1. That commit loosened
our reading so that we call check_refname_format ourselves
and just set a REF_BAD_NAME flag.
We then call create_ref_entry with the check parameter set
to 0. That function learned to do an extra safety check even
when the check parameter is 0, so that we don't load any
dangerous refnames (like "../../../etc/passwd"). This is
implemented by calling refname_is_safe() in
create_ref_entry().
However, we can observe that refname_is_safe() can only be
true if check_refname_format() also failed. So in the common
case of a sanely named ref, we perform _both_ checks, even
though we know that the latter will never trigger. This has
a noticeable performance impact when the packed-refs file is
large.
Let's drop the refname_is_safe check from create_ref_entry(),
and make it the responsibility of the caller. Of the three
callers that pass a check parameter of "0", two will have
just called check_refname_format(), and can check the
refname-safety only when it fails. The third case,
pack_if_possible_fn, is copying from an existing ref entry,
which must have previously passed our safety check.
With this patch, running "git rev-parse refs/heads/does-not-exist"
on a repo with a large (1.6GB) packed-refs file went from:
real 0m6.768s
user 0m6.340s
sys 0m0.432s
to:
real 0m5.703s
user 0m5.276s
sys 0m0.432s
for a wall-clock speedup of 15%.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git prune" used to largely ignore broken refs when deciding which
objects are still being used, which could spread an existing small
damage and make it a larger one.
* jk/prune-with-corrupt-refs:
refs.c: drop curate_packed_refs
repack: turn on "ref paranoia" when doing a destructive repack
prune: turn on ref_paranoia flag
refs: introduce a "ref paranoia" flag
t5312: test object deletion code paths in a corrupted repository
When we delete a ref, we have to rewrite the entire
packed-refs file. We take this opportunity to "curate" the
packed-refs file and drop any entries that are crufty or
broken.
Dropping broken entries (e.g., with bogus names, or ones
that point to missing objects) is actively a bad idea, as it
means that we lose any notion that the data was there in the
first place. Aside from the general hackiness that we might
lose any information about ref "foo" while deleting an
unrelated ref "bar", this may seriously hamper any attempts
by the user at recovering from the corruption in "foo".
They will lose the sha1 and name of "foo"; the exact pointer
may still be useful even if they recover missing objects
from a different copy of the repository. But worse, once the
ref is gone, there is no trace of the corruption. A
follow-up "git prune" may delete objects, even though it
would otherwise bail when seeing corruption.
We could just drop the "broken" bits from
curate_packed_refs, and continue to drop the "crufty" bits:
refs whose loose counterpart exists in the filesystem. This
is not wrong to do, and it does have the advantage that we
may write out a slightly smaller packed-refs file. But it
has two disadvantages:
1. It is a potential source of races or mistakes with
respect to these refs that are otherwise unrelated to
the operation. To my knowledge, there aren't any active
problems in this area, but it seems like an unnecessary
risk.
2. We have to spend time looking up the matching loose
refs for every item in the packed-refs file. If you
have a large number of packed refs that do not change,
that outweighs the benefit from writing out a smaller
packed-refs file (it doesn't get smaller, and you do a
bunch of directory traversal to find that out).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most operations that iterate over refs are happy to ignore
broken cruft. However, some operations should be performed
with knowledge of these broken refs, because it is better
for the operation to choke on a missing object than it is to
silently pretend that the ref did not exist (e.g., if we are
computing the set of reachable tips in order to prune
objects).
These processes could just call for_each_rawref, except that
ref iteration is often hidden behind other interfaces. For
instance, for a destructive "repack -ad", we would have to
inform "pack-objects" that we are destructive, and then it
would in turn have to tell the revision code that our
"--all" should include broken refs.
It's much simpler to just set a global for "dangerous"
operations that includes broken refs in all iterations.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Various issues around "reflog expire", e.g. using --updateref when
expiring a reflog for a symbolic reference, have been corrected
and/or made saner.
* mh/expire-updateref-fixes:
reflog_expire(): never update a reference to null_sha1
reflog_expire(): ignore --updateref for symbolic references
reflog: improve and update documentation
struct ref_lock: delete the force_write member
lock_ref_sha1_basic(): do not set force_write for missing references
write_ref_sha1(): move write elision test to callers
write_ref_sha1(): remove check for lock == NULL
Currently, if --updateref is specified and the very last reflog entry
is expired or deleted, the reference's value is set to 0{40}. This is
an invalid state of the repository, and breaks, for example, "git
fsck" and "git for-each-ref".
The only place we use --updateref in our own code is when dropping
stash entries. In that code, the very next step is to check if the
reflog has been made empty, and if so, delete the "refs/stash"
reference entirely. Thus that code path ultimately leaves the
repository in a valid state.
But we don't want to the repository in an invalid state even
temporarily, and we don't want to leave an invalid state if other
callers of "git reflog expire|delete --updateref" don't think to do
the extra cleanup step.
So, if "git reflog expire|delete" leaves no more entries in the
reflog, just leave the reference unchanged.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we are expiring reflog entries for a symbolic reference, then how
should --updateref be handled if the newest reflog entry is expired?
Option 1: Update the referred-to reference. (This is what the current
code does.) This doesn't make sense, because the referred-to reference
has its own reflog, which hasn't been rewritten.
Option 2: Update the symbolic reference itself (as in, REF_NODEREF).
This would convert the symbolic reference into a non-symbolic
reference (e.g., detaching HEAD), which is surely not what a user
would expect.
Option 3: Error out. This is plausible, but it would make the
following usage impossible:
git reflog expire ... --updateref --all
Option 4: Ignore --updateref for symbolic references.
We choose to implement option 4.
Note: another problem in this code will be fixed in a moment.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, compute the value when it is needed.
Signed-off-by: Stefan Beller <sbeller@google.com>
Edited-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a reference is missing, its SHA-1 will be null_sha1, which can't
possibly match a new value that ref_transaction_commit() is trying to
update it to. So there is no need to set force_write in this scenario.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
write_ref_sha1() previously skipped the write if the reference already
had the desired value, unless lock->force_write was set. Instead,
perform that test at the callers.
Two of the callers (in rename_ref()) unconditionally set force_write
just before calling write_ref_sha1(), so they don't need the extra
check at all. Nor do they need to set force_write anymore.
The last caller, in ref_transaction_commit(), still needs the test.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
None of the callers pass NULL to this function, and there doesn't seem
to be any usefulness to allowing them to do so.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git blame HEAD -- missing" failed to correctly say "HEAD" when it
tried to say "No such path 'missing' in HEAD".
* jk/blame-commit-label:
blame.c: fix garbled error message
use xstrdup_or_null to replace ternary conditionals
builtin/commit.c: use xstrdup_or_null instead of envdup
builtin/apply.c: use xstrdup_or_null instead of null_strdup
git-compat-util: add xstrdup_or_null helper
Add a docstring for update_ref(), emphasizing its similarity to
ref_transaction_update(). Rename its parameters to match those of
ref_transaction_update().
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If NULL is passed to ref_transaction_update()'s new_sha1 parameter,
then just verify old_sha1 (under lock) without trying to change the
new value of the reference.
Use this functionality to add a new function ref_transaction_verify(),
which checks the current value of the reference under lock but doesn't
change it.
Use ref_transaction_verify() in the implementation of "git update-ref
--stdin"'s "verify" command to avoid the awkward need to "update" the
reference to its existing value.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It makes no sense to delete a reference that is already known not to
exist.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Creating a reference requires a new_sha1 that is not NULL and not
null_sha1.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, verify the reference's old value if and only if old_sha1 is
non-NULL.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead, verify the reference's old value if and only if old_sha1 is
non-NULL.
ref_transaction_delete() will get the same treatment in a moment.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of having a separate have_old field, record this boolean value
as a bit in the "flags" field.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the following functions' "flags" arguments from "int" to
"unsigned int":
* ref_transaction_update()
* ref_transaction_create()
* ref_transaction_delete()
* update_ref()
* delete_ref()
* lock_ref_sha1_basic()
Also change the "flags" member in "struct ref_update" to unsigned.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is no reason to "reserve" a gap between the public and private
flags values.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is only used internally now. Document it a little bit better, too.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Restructure "reflog expire" to fit the reflogs better with the
recently updated ref API.
Looked reasonable (except that some shortlog entries stood out like
a sore thumb).
* mh/reflog-expire: (24 commits)
refs.c: let fprintf handle the formatting
refs.c: don't expose the internal struct ref_lock in the header file
lock_any_ref_for_update(): inline function
refs.c: remove unlock_ref/close_ref/commit_ref from the refs api
reflog_expire(): new function in the reference API
expire_reflog(): treat the policy callback data as opaque
Move newlog and last_kept_sha1 to "struct expire_reflog_cb"
expire_reflog(): move rewrite to flags argument
expire_reflog(): move verbose to flags argument
expire_reflog(): pass flags through to expire_reflog_ent()
struct expire_reflog_cb: a new callback data type
Rename expire_reflog_cb to expire_reflog_policy_cb
expire_reflog(): move updateref to flags argument
expire_reflog(): move dry_run to flags argument
expire_reflog(): add a "flags" argument
expire_reflog(): extract two policy-related functions
Extract function should_expire_reflog_ent()
expire_reflog(): use a lock_file for rewriting the reflog file
expire_reflog(): return early if the reference has no reflog
expire_reflog(): rename "ref" parameter to "refname"
...
"git blame HEAD -- missing" failed to correctly say "HEAD" when it
tried to say "No such path 'missing' in HEAD".
* jk/blame-commit-label:
blame.c: fix garbled error message
use xstrdup_or_null to replace ternary conditionals
builtin/commit.c: use xstrdup_or_null instead of envdup
builtin/apply.c: use xstrdup_or_null instead of null_strdup
git-compat-util: add xstrdup_or_null helper
* mh/reflog-expire: (24 commits)
refs.c: let fprintf handle the formatting
refs.c: don't expose the internal struct ref_lock in the header file
lock_any_ref_for_update(): inline function
refs.c: remove unlock_ref/close_ref/commit_ref from the refs api
reflog_expire(): new function in the reference API
expire_reflog(): treat the policy callback data as opaque
Move newlog and last_kept_sha1 to "struct expire_reflog_cb"
expire_reflog(): move rewrite to flags argument
expire_reflog(): move verbose to flags argument
expire_reflog(): pass flags through to expire_reflog_ent()
struct expire_reflog_cb: a new callback data type
Rename expire_reflog_cb to expire_reflog_policy_cb
expire_reflog(): move updateref to flags argument
expire_reflog(): move dry_run to flags argument
expire_reflog(): add a "flags" argument
expire_reflog(): extract two policy-related functions
Extract function should_expire_reflog_ent()
expire_reflog(): use a lock_file for rewriting the reflog file
expire_reflog(): return early if the reference has no reflog
expire_reflog(): rename "ref" parameter to "refname"
...
This replaces "x ? xstrdup(x) : NULL" with xstrdup_or_null(x).
The change is fairly mechanical, with the exception of
resolve_refdup, which can eliminate a temporary variable.
There are still a few hits grepping for "?.*xstrdup", but
these are of slightly different forms and cannot be
converted (e.g., "x ? xstrdup(x->foo) : NULL").
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Don't just reset, but release the resource held by the local
variable that is about to go out of scope.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git did not correctly read an overlong refname from a packed refs
file.
* jk/read-packed-refs-without-path-max:
read_packed_refs: use skip_prefix instead of static array
read_packed_refs: pass strbuf to parse_ref_line
read_packed_refs: use a strbuf for reading lines
The code that reads the reflog from the newer to the older entries
did not handle an entry that crosses a boundary of block it uses to
read them correctly.
* jk/for-each-reflog-ent-reverse:
for_each_reflog_ent_reverse: turn leftover check into assertion
for_each_reflog_ent_reverse: fix newlines on block boundaries
"git remote update --prune" to drop many refs has been optimized.
* mh/simplify-repack-without-refs:
sort_string_list(): rename to string_list_sort()
prune_remote(): iterate using for_each_string_list_item()
prune_remote(): rename local variable
repack_without_refs(): make the refnames argument a string_list
prune_remote(): sort delete_refs_list references en masse
prune_remote(): initialize both delete_refs lists in a single loop
prune_remote(): exit early if there are no stale references
Instead of calculating whether to put a plus or minus sign, offload
the responsibilty to the fprintf function.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now the struct ref_lock is used completely internally, so let's
remove it from the header file.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Inline the function at its one remaining caller (which is within
refs.c) and remove it.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
unlock|close|commit_ref can be made static since there are no more external
callers.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move expire_reflog() into refs.c and rename it to reflog_expire().
Turn the three policy functions into function pointers that are passed
into reflog_expire(). Add function prototypes and documentation to
refs.h.
[jc: squashed in $gmane/261582, drop "extern" in function definition]
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Tweaked-by: Ramsay Jones
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Break out the code to create the string and writing it to the file
descriptor from log_ref_write and add it into a dedicated function
log_ref_write_fd. It is a nice unit of work.
For now this is only used from log_ref_write, but in the future it
might have other callers.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We want to recognize the packed-refs header and skip to the
"traits" part of the line. We currently do it by feeding
sizeof() a static const array to strncmp. However, it's a
bit simpler to just skip_prefix, which expresses the
intention more directly, and without remembering to account
for the NUL-terminator in each sizeof() call.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we have a strbuf in read_packed_refs, we can pass
it straight to the line parser, which saves us an extra
strlen.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Current code uses a fixed PATH_MAX-sized buffer for reading
packed-refs lines. This is a reasonable guess, in the sense
that git generally cannot work with refs larger than
PATH_MAX. However, there are a few cases where it is not
great:
1. Some systems may have a low value of PATH_MAX, but can
actually handle larger paths in practice. Fixing this
code path probably isn't enough to make them work
completely with long refs, but it is a step in the
right direction.
2. We use fgets, which will happily give us half a line on
the first read, and then the rest of the line on the
second. This is probably OK in practice, because our
refline parser is careful enough to look for the
trailing newline on the first line. The second line may
look like a peeled line to us, but since "^" is illegal
in refnames, it is not likely to come up.
Still, it does not hurt to be more careful.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our loop should always process all lines, even if we hit the
beginning of the file. We have a conditional after the loop
ends to double-check that there is nothing left and to
process it. But this should never happen, and is a sign of a
logic bug in the loop. Let's turn it into a BUG assertion.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we read a reflog file in reverse, we read whole chunks
of BUFSIZ bytes, then loop over the buffer, parsing any
lines we find. We find the beginning of each line by looking
for the newline from the previous line. If we don't find
one, we know that we are either at the beginning of
the file, or that we have to read another block.
In the latter case, we stuff away what we have into a
strbuf, read another block, and continue our parse. But we
missed one case here. If we did find a newline, and it is at
the beginning of the block, we must also stuff that newline
into the strbuf, as it belongs to the block we are about to
read.
The minimal fix here would be to add this special case to
the conditional that checks whether we found a newline.
But we can make the flow a little clearer by rearranging a
bit: we first handle lines that we are going to show, and
then at the end of each loop, stuff away any leftovers if
necessary. That lets us fold this special-case in with the
more common "we ended in the middle of a line" case.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The ref_transaction_update function can already be used to create refs by
passing null_sha1 as the old_sha1 parameter. Simplify by replacing
transaction_create with a thin wrapper.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the previous patch, git_snpath() is modified to allocate a new
strbuf buffer because vsnpath() needs that. But that makes it
awkward because git_snpath() receives a pre-allocated buffer from
outside and has to copy data back. Rename it to strbuf_git_path()
and make it receive strbuf directly.
Using git_path() in update_refs_for_switch() which used to call
git_snpath() is safe because that function and all of its callers do
not keep any pointer to the round-robin buffer pool allocated by
get_pathname().
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before the previous commit, get_pathname returns an array of PATH_MAX
length. Even if git_path() and similar functions does not use the
whole array, git_path() caller can, in theory.
After the commit, get_pathname() may return a buffer that has just
enough room for the returned string and git_path() caller should never
write beyond that.
Make git_path(), mkpath() and git_path_submodule() return a const
buffer to make sure callers do not write in it at all.
This could have been part of the previous commit, but the "const"
conversion is too much distraction from the core changes in path.c.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of the callers have string_lists available already, whereas two
of them had to read data out of a string_list into an array of strings
just to call this function. So change repack_without_refs() to take
the list of refnames to omit as a string_list, and change the callers
accordingly.
Suggested-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
lock_ref_sha1_basic is inconsistent about when it calls
die() and when it returns NULL to signal an error. This is
annoying to any callers that want to recover from a locking
error.
This seems to be mostly historical accident. It was added in
4bd18c4 (Improve abstraction of ref lock/write.,
2006-05-17), which returned an error in all cases except
calling safe_create_leading_directories, in which case it
died. Later, 40aaae8 (Better error message when we are
unable to lock the index file, 2006-08-12) asked
hold_lock_file_for_update to die for us, leaving the
resolve_ref code-path the only one which returned NULL.
We tried to correct that in 5cc3cef (lock_ref_sha1(): do not
sometimes error() and sometimes die()., 2006-09-30),
by converting all of the die() calls into returns. But we
missed the "die" flag passed to the lock code, leaving us
inconsistent. This state persisted until e5c223e
(lock_ref_sha1_basic(): if locking fails with ENOENT, retry,
2014-01-18). Because of its retry scheme, it does not ask
the lock code to die, but instead manually dies with
unable_to_lock_die().
We can make this consistent with the other return paths by
converting this to use unable_to_lock_message(), and
returning NULL. This is safe to do because all callers
already needed to check the return value of the function,
since it could fail (and return NULL) for other reasons.
[jk: Added excessive history explanation]
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Corner-case bugfixes for "git fetch" around reflog handling.
* jk/fetch-reflog-df-conflict:
ignore stale directories when checking reflog existence
fetch: load all default config at startup
When we update a ref, we have two rules for whether or not
we actually update the reflog:
1. If the reflog already exists, we will always append to
it.
2. If log_all_ref_updates is set, we will create a new
reflog file if necessary.
We do the existence check by trying to open the reflog file,
either with or without O_CREAT (depending on log_all_ref_updates).
If it fails, then we check errno to see what happened.
If we were not using O_CREAT and we got ENOENT, the file
doesn't exist, and we return success (there isn't a reflog
already, and we were not told to make a new one).
If we get EISDIR, then there is likely a stale directory
that needs to be removed (e.g., there used to be "foo/bar",
it was deleted, and the directory "foo" was left. Now we
want to create the ref "foo"). If O_CREAT is set, then we
catch this case, try to remove the directory, and retry our
open. So far so good.
But if we get EISDIR and O_CREAT is not set, then we treat
this as any other error, which is not right. Like ENOENT,
EISDIR is an indication that we do not have a reflog, and we
should silently return success (we were not told to create
it). Instead, the current code reports this as an error, and
we fail to update the ref at all.
Note that this is relatively unlikely to happen, as you
would have to have had reflogs turned on, and then later
turned them off (it could also happen due to a bug in fetch,
but that was fixed in the previous commit). However, it's
quite easy to fix: we just need to treat EISDIR like ENOENT
for the non-O_CREAT case, and silently return (note that
this early return means we can also simplify the O_CREAT
case).
Our new tests cover both cases (O_CREAT and non-O_CREAT).
The first one already worked, of course.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When removal of a loose or packed ref fails, bail out instead of
trying to finish the transaction. This way, a single error message
can be printed (instead of multiple messages being concatenated by
mistake) and the operator can try to solve the underlying problem
before there is a chance to muck things up even more.
In particular, when git fails to remove a ref, git goes on to try to
delete the reflog. Exiting early lets us keep the reflog.
When git succeeds in deleting a ref A and fails to remove a ref B, it
goes on to try to delete both reflogs. It would be better to just
remove the reflog for A, but that would be a more invasive change.
Failing early means we keep both reflogs, which puts the operator in a
good position to understand the problem and recover.
A long term goal is to avoid these problems altogether and roll back
the transaction on failure. That kind of transactionality will have
to wait for a later series (the plan for which is to make all
destructive work happen in a single update of the packed-refs file).
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some functions that take a strbuf argument to append an error treat
!err as an indication that the message should be suppressed (e.g.,
ref_update_reject_duplicates). Others write the message to stderr on
!err (e.g., repack_without_refs). Others crash (e.g.,
ref_transaction_update).
Some of these behaviors are for historical reasons and others were
accidents. Luckily no callers pass err == NULL any more. Simplify
by consistently requiring the strbuf argument.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We currently do not handle badly named refs well:
$ cp .git/refs/heads/master .git/refs/heads/master.....@\*@\\.
$ git branch
fatal: Reference has invalid format: 'refs/heads/master.....@*@\.'
$ git branch -D master.....@\*@\\.
error: branch 'master.....@*@\.' not found.
Users cannot recover from a badly named ref without manually finding
and deleting the loose ref file or appropriate line in packed-refs.
Making that easier will make it easier to tweak the ref naming rules
in the future, for example to forbid shell metacharacters like '`'
and '"', without putting people in a state that is hard to get out of.
So allow "branch --list" to show these refs and allow "branch -d/-D"
and "update-ref -d" to delete them. Other commands (for example to
rename refs) will continue to not handle these refs but can be changed
in later patches.
Details:
In resolving functions, refuse to resolve refs that don't pass the
git-check-ref-format(1) check unless the new RESOLVE_REF_ALLOW_BAD_NAME
flag is passed. Even with RESOLVE_REF_ALLOW_BAD_NAME, refuse to
resolve refs that escape the refs/ directory and do not match the
pattern [A-Z_]* (think "HEAD" and "MERGE_HEAD").
In locking functions, refuse to act on badly named refs unless they
are being deleted and either are in the refs/ directory or match [A-Z_]*.
Just like other invalid refs, flag resolved, badly named refs with the
REF_ISBROKEN flag, treat them as resolving to null_sha1, and skip them
in all iteration functions except for for_each_rawref.
Flag badly named refs (but not symrefs pointing to badly named refs)
with a REF_BAD_NAME flag to make it easier for future callers to
notice and handle them specially. For example, in a later patch
for-each-ref will use this flag to detect refs whose names can confuse
callers parsing for-each-ref output.
In the transaction API, refuse to create or update badly named refs,
but allow deleting them (unless they try to escape refs/ and don't match
[A-Z_]*).
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since v1.7.9-rc1~10^2 (write_head_info(): handle "extra refs" locally,
2012-01-06), this trick to keep track of ".have" refs that are only
valid on the wire and not on the filesystem is not needed any more.
Simplify by removing support for the REFNAME_DOT_COMPONENT flag.
This means we'll be slightly stricter with invalid refs found in a
packed-refs file or during clone. read_loose_refs() already checks
for and skips refnames with .components so it is not affected.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a repository gets in a broken state with too much symref nesting,
it cannot be repaired with "git branch -d":
$ git symbolic-ref refs/heads/nonsense refs/heads/nonsense
$ git branch -d nonsense
error: branch 'nonsense' not found.
Worse, "git update-ref --no-deref -d" doesn't work for such repairs
either:
$ git update-ref -d refs/heads/nonsense
error: unable to resolve reference refs/heads/nonsense: Too many levels of symbolic links
Fix both by teaching resolve_ref_unsafe a new RESOLVE_REF_NO_RECURSE
flag and passing it when appropriate.
Callers can still read the value of a symref (for example to print a
message about it) with that flag set --- resolve_ref_unsafe will
resolve one level of symrefs and stop there.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
resolve_ref_unsafe takes a boolean argument for reading (a nonexistent ref
resolves successfully for writing but not for reading). Change this to be
a flags field instead, and pass the new constant RESOLVE_REF_READING when
we want this behaviour.
While at it, swap two of the arguments in the function to put output
arguments at the end. As a nice side effect, this ensures that we can
catch callers that were unaware of the new API so they can be audited.
Give the wrapper functions resolve_refdup and read_ref_full the same
treatment for consistency.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
No external users call write_ref_sha1 any more so let's declare it static.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In _commit, ENOTDIR can happen in the call to lock_ref_sha1_basic, either
when we lstat the new refname or if the name checking function reports that
the same type of conflict happened. In both cases, it means that we can not
create the new ref due to a name conflict.
Start defining specific return codes for _commit. TRANSACTION_NAME_CONFLICT
refers to a failure to create a ref due to a name conflict with another ref.
TRANSACTION_GENERIC_ERROR is for all other errors.
When "git fetch" is creating refs, name conflicts differ from other errors in
that they are likely to be resolved by running "git remote prune <remote>".
"git fetch" currently inspects errno to decide whether to give that advice.
Once it switches to the transaction API, it can check for
TRANSACTION_NAME_CONFLICT instead.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change is_refname_available to take a list of strings to exclude when
checking for conflicts instead of just one single name. We can already
exclude a single name for the sake of renames. This generalizes that support.
ref_transaction_commit already tracks a set of refs that are being deleted
in an array. This array is then used to exclude refs from being written to
the packed-refs file. At some stage we will want to change this array to a
struct string_list and then we can pass it to is_refname_available via the
call to lock_ref_sha1_basic. That will allow us to perform transactions
that perform multiple renames as long as there are no conflicts within the
starting or ending state.
For example, that would allow a single transaction that contains two
renames that are both individually conflicting:
m -> n/n
n -> m/m
No functional change intended yet.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Skip using the lock_any_ref_for_update wrapper and call lock_ref_sha1_basic
directly from the commit function.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the check for check_refname_format from lock_any_ref_for_update to
lock_ref_sha1_basic. At some later stage we will get rid of
lock_any_ref_for_update completely. This has no visible impact to callers
except for the inability to lock badly named refs, which is not possible
today already for other reasons.(*)
Keep lock_any_ref_for_update as a no-op wrapper. It is the public facing
version of this interface and keeping it as a separate function will make
it easier to experiment with the internal lock_ref_sha1_basic signature.
(*) For example, if lock_ref_sha1_basic checks the refname format and
refuses to lock badly named refs, it will not be possible to delete
such refs because the first step of deletion is to lock the ref. We
currently already fail in that case because these refs are not recognized
to exist:
$ cp .git/refs/heads/master .git/refs/heads/echo...\*\*
$ git branch -D .git/refs/heads/echo...\*\*
error: branch '.git/refs/heads/echo...**' not found.
This has been broken for a while. Later patches in the series will start
repairing the handling of badly named refs.
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
