If the original version of `write_locked_index()` returned with an
error, it didn't roll back the lockfile unless the error occured at the
very end, during closing/committing. See commit 03b866477 (read-cache:
new API write_locked_index instead of write_index/write_cache,
2014-06-13).
In commit 9f41c7a6b (read-cache: close index.lock in do_write_index,
2017-04-26), we learned to close the lock slightly earlier in the
callstack. That was mostly a side-effect of lockfiles being implemented
using temporary files, but didn't cause any real harm.
Recently, commit 076aa2cbd (tempfile: auto-allocate tempfiles on heap,
2017-09-05) introduced a subtle bug. If the temporary file is deleted
(i.e., the lockfile is rolled back), the tempfile-pointer in the `struct
lock_file` will be left dangling. Thus, an attempt to reuse the
lockfile, or even just to roll it back, will induce undefined behavior
-- most likely a crash.
Besides not crashing, we clearly want to make things consistent. The
guarantees which the lockfile-machinery itself provides is A) if we ask
to commit and it fails, roll back, and B) if we ask to close and it
fails, do _not_ roll back. Let's do the same for consistency.
Do not delete the temporary file in `do_write_index()`. One of its
callers, `write_locked_index()` will thereby avoid rolling back the
lock. The other caller, `write_shared_index()`, will delete its
temporary file anyway. Both of these callers will avoid undefined
behavior (crashing).
Teach `write_locked_index(..., COMMIT_LOCK)` to roll back the lock
before returning. If we have already succeeded and committed, it will be
a noop. Simplify the existing callers where we now have a superfluous
call to `rollback_lockfile()`. That should keep future readers from
wondering why the callers are inconsistent.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is no longer any need to allocate and leak a `struct lock_file`.
The previous patch addressed an instance where we needed a minor tweak
alongside the trivial changes.
Deal with the remaining instances where we allocate and leak a struct
within a single function. Change them to have the `struct lock_file` on
the stack instead.
These instances were identified by running `git grep "^\s*struct
lock_file\s*\*"`.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert parse_tree_indirect to take a pointer to struct object_id.
Update all the callers. This transformation was achieved using the
following semantic patch and manual updates to the declaration and
definition. Update builtin/checkout.c manually as well, since it uses a
ternary expression not handled by the semantic patch.
@@
expression E1;
@@
- parse_tree_indirect(E1.hash)
+ parse_tree_indirect(&E1)
@@
expression E1;
@@
- parse_tree_indirect(E1->hash)
+ parse_tree_indirect(E1)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Converting checkout_fast_forward is required to convert
parse_tree_indirect.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "libify sequencer" topic stopped passing the die_on_error option
to hold_locked_index(), and this lost an error message from "git
merge --ff-only $commit" when there are competing updates in
progress.
The command still exits with a non-zero status, but that is not of
much help for an interactive user. The last thing the command says
is "Updating $from..$to". We used to follow it with a big error
message that makes it clear that "merge --ff-only" did not succeed.
What is sad is that we should have noticed this regression while
reviewing the change. It was clear that the update to the
checkout_fast_forward() function made a failing hold_locked_index()
silent, but the only caller of the checkout_fast_forward() function
had this comment:
if (checkout_fast_forward(from, to, 1))
- exit(128); /* the callee should have complained already */
+ return -1; /* the callee should have complained already */
which clearly contradicted the assumption X-<.
Add a new option LOCK_REPORT_ON_ERROR that can be passed instead of
LOCK_DIE_ON_ERROR to the hold_lock*() family of functions and teach
checkout_fast_forward() to use it to fix this regression.
After going thourgh all calls to hold_lock*() family of functions
that used to pass LOCK_DIE_ON_ERROR but were modified to pass 0 in
the "libify sequencer" topic "git show --first-parent 2a4062a4a8",
it appears that this is the only one that has become silent. Many
others used to give detailed report that talked about "there may be
competing Git process running" but with the series merged they now
only give a single liner "Unable to lock ...", some of which may
have to be tweaked further, but at least they say something, unlike
the one this patch fixes.
Reported-by: Robbie Iannucci <iannucci@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of dying there, let the caller high up in the callchain
notice the error and handle it (by dying, still).
The only callers of checkout_fast_forward(), cmd_merge(),
pull_into_void(), cmd_pull() and sequencer's fast_forward_to(),
already check the return value and handle it appropriately. With this
step, we make it notice an error return from this function.
So this is a safe conversion to make checkout_fast_forward()
callable from new callers that want it not to die, without changing
the external behaviour of anything existing.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
struct object is one of the major data structures dealing with object
IDs. Convert it to use struct object_id instead of an unsigned char
array. Convert get_object_hash to refer to the new member as well.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
Move the interface declaration for the functions in lockfile.c from
cache.h to a new file, lockfile.h. Add #includes where necessary (and
remove some redundant includes of cache.h by files that already
include builtin.h).
Move the documentation of the lock_file state diagram from lockfile.c
to the new header file.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An experiment to use two files (the base file and incremental
changes relative to it) to represent the index to reduce I/O cost
of rewriting a large index when only small part of the working tree
changes.
* nd/split-index: (32 commits)
t1700: new tests for split-index mode
t2104: make sure split index mode is off for the version test
read-cache: force split index mode with GIT_TEST_SPLIT_INDEX
read-tree: note about dropping split-index mode or index version
read-tree: force split-index mode off on --index-output
rev-parse: add --shared-index-path to get shared index path
update-index --split-index: do not split if $GIT_DIR is read only
update-index: new options to enable/disable split index mode
split-index: strip pathname of on-disk replaced entries
split-index: do not invalidate cache-tree at read time
split-index: the reading part
split-index: the writing part
read-cache: mark updated entries for split index
read-cache: save deleted entries in split index
read-cache: mark new entries for split index
read-cache: split-index mode
read-cache: save index SHA-1 after reading
entry.c: update cache_changed if refresh_cache is set in checkout_entry()
cache-tree: mark istate->cache_changed on prime_cache_tree()
cache-tree: mark istate->cache_changed on cache tree update
...
This is shorter, and avoids a rather complicated set of
allocation and free steps.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These functions are called in sequencer.c, which is part of
libgit.a. This makes libgit.a potentially require builtin/merge.c for
external git commands.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Martin Ågren
brian m. carlson
Junio C Hamano
Johannes Schindelin
Michael Haggerty
Jeff King
Nguyễn Thái Ngọc Duy