| Age | Commit message (Collapse) | Author | Files | Lines |
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Add --expiry-date as a data-type for config files when
'git config --get' is used. This will return any relative
or fixed dates from config files as timestamps.
This is useful for scripts (e.g. gc.reflogexpire) that work
with timestamps so that '2.weeks' can be converted to a format
acceptable by those scripts/functions.
Following the convention of git_config_pathname(), move
the helper function required for this feature from
builtin/reflog.c to builtin/config.c where other similar
functions exist (e.g. for --bool or --path), and match
the order of parameters with other functions (i.e. output
pointer as first parameter).
Signed-off-by: Haaris Mehmood <hsed@unimetic.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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reflog_expire already used struct object_id internally, but it did not
take it as a parameter. Adjust the parameter (and the callers) to pass
a pointer to struct object_id instead of a pointer to unsigned char.
Remove the temporary inserted earlier as it is no longer required.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Convert the remaining uses of unsigned char [20] to struct object_id.
This conversion is needed for dwim_log.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In a couple of places, we pop objects off an object array `foo` by
decreasing `foo.nr`. We access `foo.nr` in many places, but most if not
all other times we do so read-only, e.g., as we iterate over the array.
But when we change `foo.nr` behind the array's back, it feels a bit
nasty and looks like it might leak memory.
Leaks happen if the popped element has an allocated `name` or `path`.
At the moment, that is not the case. Still, 1) the object array might
gain more fields that want to be freed, 2) a code path where we pop
might start using names or paths, 3) one of these code paths might be
copied to somewhere where we do, and 4) using a dedicated function for
popping is conceptually cleaner.
Introduce and use `object_array_pop()` instead. Release memory in the
new function. Document that popping an object leaves the associated
elements in limbo.
The converted places were identified by grepping for "\.nr\>" and
looking for "--".
Make the new function return NULL on an empty array. This is consistent
with `pop_commit()` and allows the following:
while ((o = object_array_pop(&foo)) != NULL) {
// do something
}
But as noted above, we don't need to go out of our way to avoid reading
`foo.nr`. This is probably more readable:
while (foo.nr) {
... o = object_array_pop(&foo);
// do something
}
The name of `object_array_pop()` does not quite align with
`add_object_array()`. That is unfortunate. On the other hand, it matches
`object_array_clear()`. Arguably it's `add_...` that is the odd one out,
since it reads like it's used to "add" an "object array". For that
reason, side with `object_array_clear()`.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Instead of freeing `foo.objects` for an object array `foo` (sometimes
conditionally), call `object_array_clear(&foo)`. This means we don't
poke as much into the implementation, which is already a good thing, but
also that we release the individual entries as well, thereby fixing at
least one memory-leak (in diff-lib.c).
If someone is holding on to a pointer to an element's `name` or `path`,
that is now a dangling pointer, i.e., we'd be turning an unpleasant
situation into an outright bug. To the best of my understanding no such
long-term pointers are being taken.
The way we handle `study` in builting/reflog.c still looks like it might
leak. That will be addressed in the next commit.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Minor code cleanup.
* ab/wildmatch:
wildmatch: remove unused wildopts parameter
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Fix configuration codepath to pay proper attention to commondir
that is used in multi-worktree situation, and isolate config API
into its own header file.
* bw/config-h:
config: don't implicitly use gitdir or commondir
config: respect commondir
setup: teach discover_git_directory to respect the commondir
config: don't include config.h by default
config: remove git_config_iter
config: create config.h
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Remove the unused wildopts placeholder struct from being passed to all
wildmatch() invocations, or rather remove all the boilerplate NULL
parameters.
This parameter was added back in commit 9b3497cab9 ("wildmatch: rename
constants and update prototype", 2013-01-01) as a placeholder for
future use. Over 4 years later nothing has made use of it, let's just
remove it. It can be added in the future if we find some reason to
start using such a parameter.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Stop including config.h by default in cache.h. Instead only include
config.h in those files which require use of the config system.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Conversion from uchar[20] to struct object_id continues.
* bc/object-id: (53 commits)
object: convert parse_object* to take struct object_id
tree: convert parse_tree_indirect to struct object_id
sequencer: convert do_recursive_merge to struct object_id
diff-lib: convert do_diff_cache to struct object_id
builtin/ls-tree: convert to struct object_id
merge: convert checkout_fast_forward to struct object_id
sequencer: convert fast_forward_to to struct object_id
builtin/ls-files: convert overlay_tree_on_cache to object_id
builtin/read-tree: convert to struct object_id
sha1_name: convert internals of peel_onion to object_id
upload-pack: convert remaining parse_object callers to object_id
revision: convert remaining parse_object callers to object_id
revision: rename add_pending_sha1 to add_pending_oid
http-push: convert process_ls_object and descendants to object_id
refs/files-backend: convert many internals to struct object_id
refs: convert struct ref_update to use struct object_id
ref-filter: convert some static functions to struct object_id
Convert struct ref_array_item to struct object_id
Convert the verify_pack callback to struct object_id
Convert lookup_tag to struct object_id
...
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Make parse_object, parse_object_or_die, and parse_object_buffer take a
pointer to struct object_id. Remove the temporary variables inserted
earlier, since they are no longer necessary. Transform all of the
callers using the following semantic patch:
@@
expression E1;
@@
- parse_object(E1.hash)
+ parse_object(&E1)
@@
expression E1;
@@
- parse_object(E1->hash)
+ parse_object(E1)
@@
expression E1, E2;
@@
- parse_object_or_die(E1.hash, E2)
+ parse_object_or_die(&E1, E2)
@@
expression E1, E2;
@@
- parse_object_or_die(E1->hash, E2)
+ parse_object_or_die(E1, E2)
@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1.hash, E2, E3, E4, E5)
+ parse_object_buffer(&E1, E2, E3, E4, E5)
@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1->hash, E2, E3, E4, E5)
+ parse_object_buffer(E1, E2, E3, E4, E5)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Convert the lookup_tree function to take a pointer to struct object_id.
The commit was created with manual changes to tree.c, tree.h, and
object.c, plus the following semantic patch:
@@
@@
- lookup_tree(EMPTY_TREE_SHA1_BIN)
+ lookup_tree(&empty_tree_oid)
@@
expression E1;
@@
- lookup_tree(E1.hash)
+ lookup_tree(&E1)
@@
expression E1;
@@
- lookup_tree(E1->hash)
+ lookup_tree(E1)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Convert lookup_commit, lookup_commit_or_die,
lookup_commit_reference, and lookup_commit_reference_gently to take
struct object_id arguments.
Introduce a temporary in parse_object buffer in order to convert this
function. This is required since in order to convert parse_object and
parse_object_buffer, lookup_commit_reference_gently and
lookup_commit_or_die would need to be converted. Not introducing a
temporary would therefore require that lookup_commit_or_die take a
struct object_id *, but lookup_commit would take unsigned char *,
leaving a confusing and hard-to-use interface.
parse_object_buffer will lose this temporary in a later patch.
This commit was created with manual changes to commit.c, commit.h, and
object.c, plus the following semantic patch:
@@
expression E1, E2;
@@
- lookup_commit_reference_gently(E1.hash, E2)
+ lookup_commit_reference_gently(&E1, E2)
@@
expression E1, E2;
@@
- lookup_commit_reference_gently(E1->hash, E2)
+ lookup_commit_reference_gently(E1, E2)
@@
expression E1;
@@
- lookup_commit_reference(E1.hash)
+ lookup_commit_reference(&E1)
@@
expression E1;
@@
- lookup_commit_reference(E1->hash)
+ lookup_commit_reference(E1)
@@
expression E1;
@@
- lookup_commit(E1.hash)
+ lookup_commit(&E1)
@@
expression E1;
@@
- lookup_commit(E1->hash)
+ lookup_commit(E1)
@@
expression E1, E2;
@@
- lookup_commit_or_die(E1.hash, E2)
+ lookup_commit_or_die(&E1, E2)
@@
expression E1, E2;
@@
- lookup_commit_or_die(E1->hash, E2)
+ lookup_commit_or_die(E1, E2)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Adjust the callback functions to take struct object_id * instead of
unsigned char *, and modify related static functions accordingly.
Introduce a temporary object_id instance into files_reflog_expire and
copy the SHA-1 value passed in. This is necessary because the sha1
parameter can come indirectly from get_sha1. Without the temporary, it
would require much more refactoring to be able to convert this function.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git's source code assumes that unsigned long is at least as precise as
time_t. Which is incorrect, and causes a lot of problems, in particular
where unsigned long is only 32-bit (notably on Windows, even in 64-bit
versions).
So let's just use a more appropriate data type instead. In preparation
for this, we introduce the new `timestamp_t` data type.
By necessity, this is a very, very large patch, as it has to replace all
timestamps' data type in one go.
As we will use a data type that is not necessarily identical to `time_t`,
we need to be very careful to use `time_t` whenever we interact with the
system functions, and `timestamp_t` everywhere else.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Make each_reflog_ent_fn take two struct object_id pointers instead of
two pointers to unsigned char. Convert the various callbacks to use
struct object_id as well. Also, rename fsck_handle_reflog_sha1 to
fsck_handle_reflog_oid.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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You can tweak the reflog expiration for a particular subset
of refs by configuring gc.foo.reflogexpire. We keep a linked
list of reflog_expire_cfg structs, each of which holds the
pattern and a "len" field for the length of the pattern. The
pattern itself is _not_ NUL-terminated.
However, we feed the pattern directly to wildmatch(), which
expects a NUL-terminated string, meaning it may keep reading
random junk after our struct.
We can fix this by allocating an extra byte for the NUL
(which is already zero because we use xcalloc). Let's also
drop the misleading "len" field, which is no longer
necessary. The existing use of "len" can be converted to use
strncmp().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object. This provides no
functional change, as it is essentially a macro substitution.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
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Convert most instances where the sha1 member of struct object is
dereferenced to use get_object_hash. Most instances that are passed to
functions that have versions taking struct object_id, such as
get_sha1_hex/get_oid_hex, or instances that can be trivially converted
to use struct object_id instead, are not converted.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
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Code simplification.
* rs/pop-commit:
use pop_commit() for consuming the first entry of a struct commit_list
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Instead of open-coding the function pop_commit() just call it. This
makes the intent clearer and reduces code size.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Error string fix.
* ah/reflog-typofix-in-error:
reflog: add missing single quote to error message
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The error message can be seen by running
`git config gc.reflogexpire foo` and then `git reflog expire`.
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This is necessary because alternate ref backends might store reflogs
somewhere other than .git/logs. Code that now directly manipulates
.git/logs should instead go through git-reflog.
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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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>
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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>
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Revamp the "git reflog" usage documentation in the manpage and the
command help to match the current reality and improve its clarity:
* Add documentation for some options that had been left out.
* Group the subcommands and options more logically and move more
common subcommands/options higher.
* Improve some explanations.
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>
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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>
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Now that expire_reflog() doesn't actually look in the
expire_reflog_policy_cb data structure, we can make it opaque:
* Change the callers of expire_reflog() to pass it a pointer to an
entire "struct expire_reflog_policy_cb" rather than a pointer to a
"struct cmd_reflog_expire_cb".
* Change expire_reflog() to accept the argument as a "void *" and
simply pass it through to the policy functions.
* Change the policy functions, reflog_expiry_prepare(),
reflog_expiry_cleanup(), and should_expire_reflog_ent(), to accept
"void *cb_data" arguments and cast them back to "struct
expire_reflog_policy_cb" internally.
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>
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These members are not needed by the policy functions.
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>
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The policy objects don't care about "--rewrite". So move it to
expire_reflog()'s flags parameter.
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>
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The policy objects don't care about "--verbose". So move it to
expire_reflog()'s flags parameter.
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>
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Add a flags field to "struct expire_reflog_cb", and pass the flags
argument through to expire_reflog_ent(). In a moment we will start
using it to pass through flags that expire_reflog_ent() needs.
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>
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Add a new data type, "struct expire_reflog_cb", for holding the data
that expire_reflog() passes to expire_reflog_ent() via
for_each_reflog_ent(). For now it only holds a pointer to a "struct
expire_reflog_policy_cb", which still contains all of the actual data.
In future commits we will move some fields from the latter to the
former.
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>
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This is the first step towards separating the data needed by the
policy code from the data needed by the reflog expiration machinery.
(In a moment we will add a *new* "struct expire_reflog_cb" for the use
of expire_reflog() itself, then move fields selectively from
expire_reflog_policy_cb to expire_reflog_cb.)
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>
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The policy objects don't care about "--updateref". So move it to
expire_reflog()'s flags parameter.
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>
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The policy objects don't care about "--dry-run". So move it to
expire_reflog()'s flags parameter.
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>
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We want to separate the options relevant to the expiry machinery from
the options affecting the expiration policy. So add a "flags" argument
to expire_reflog() to hold the former.
The argument doesn't yet do anything.
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>
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Extract two functions, reflog_expiry_prepare() and
reflog_expiry_cleanup(), from expire_reflog(). This is a further step
towards separating the code for deciding on expiration policy from the
code that manages the physical deletion of reflog entries.
This change requires a couple of local variables from expire_reflog()
to be turned into fields of "struct expire_reflog_cb". More
reorganization of the callback data will follow in later commits.
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>
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Extract from expire_reflog_ent() a function that is solely responsible
for deciding whether a reflog entry should be expired. By separating
this "business logic" from the mechanics of actually expiring entries,
we are working towards the goal of encapsulating reflog expiry within
the refs API, with policy decided by a callback function passed to it
by its caller.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We don't actually need the locking functionality, because we already
hold the lock on the reference itself, which is how the reflog file is
locked. But the lock_file code can do some of the bookkeeping for us,
and it is more careful than the old code here was. For example:
* It correctly handles the case that the reflog lock file already
exists for some reason or cannot be opened.
* It correctly cleans up the lockfile if the program dies.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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There is very little cleanup needed if the reference has no reflog. If
we move the initialization of log_file down a bit, there's even less.
So instead of jumping to the cleanup code at the end of the function,
just do the cleanup and return inline.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This is our usual convention.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Prior to v1.5.4~14, expire_reflog() had to be an each_ref_fn because
it was passed to for_each_reflog(). Since then, there has been no
reason for it to implement the each_ref_fn interface. So...
* Remove the "unused" parameter (which took the place of "flags", but
was really unused).
* Declare the last parameter to be (struct cmd_reflog_expire_cb *)
rather than (void *).
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Tighten the logic to decide that an unreachable cruft is
sufficiently old by covering corner cases such as an ancient object
becoming reachable and then going unreachable again, in which case
its retention period should be prolonged.
* jk/prune-mtime: (28 commits)
drop add_object_array_with_mode
revision: remove definition of unused 'add_object' function
pack-objects: double-check options before discarding objects
repack: pack objects mentioned by the index
pack-objects: use argv_array
reachable: use revision machinery's --indexed-objects code
rev-list: add --indexed-objects option
rev-list: document --reflog option
t5516: test pushing a tag of an otherwise unreferenced blob
traverse_commit_list: support pending blobs/trees with paths
make add_object_array_with_context interface more sane
write_sha1_file: freshen existing objects
pack-objects: match prune logic for discarding objects
pack-objects: refactor unpack-unreachable expiration check
prune: keep objects reachable from recent objects
sha1_file: add for_each iterators for loose and packed objects
count-objects: use for_each_loose_file_in_objdir
count-objects: do not use xsize_t when counting object size
prune-packed: use for_each_loose_file_in_objdir
reachable: mark index blobs as SEEN
...
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Our current strategy with prune is that an object falls into
one of three categories:
1. Reachable (from ref tips, reflogs, index, etc).
2. Not reachable, but recent (based on the --expire time).
3. Not reachable and not recent.
We keep objects from (1) and (2), but prune objects in (3).
The point of (2) is that these objects may be part of an
in-progress operation that has not yet updated any refs.
However, it is not always the case that objects for an
in-progress operation will have a recent mtime. For example,
the object database may have an old copy of a blob (from an
abandoned operation, a branch that was deleted, etc). If we
create a new tree that points to it, a simultaneous prune
will leave our tree, but delete the blob. Referencing that
tree with a commit will then work (we check that the tree is
in the object database, but not that all of its referred
objects are), as will mentioning the commit in a ref. But
the resulting repo is corrupt; we are missing the blob
reachable from a ref.
One way to solve this is to be more thorough when
referencing a sha1: make sure that not only do we have that
sha1, but that we have objects it refers to, and so forth
recursively. The problem is that this is very expensive.
Creating a parent link would require traversing the entire
object graph!
Instead, this patch pushes the extra work onto prune, which
runs less frequently (and has to look at the whole object
graph anyway). It creates a new category of objects: objects
which are not recent, but which are reachable from a recent
object. We do not prune these objects, just like the
reachable and recent ones.
This lets us avoid the recursive check above, because if we
have an object, even if it is unreachable, we should have
its referent. We can make a simple inductive argument that
with this patch, this property holds (that there are no
objects with missing referents in the repository):
0. When we have no objects, we have nothing to refer or be
referred to, so the property holds.
1. If we add objects to the repository, their direct
referents must generally exist (e.g., if you create a
tree, the blobs it references must exist; if you create
a commit to point at the tree, the tree must exist).
This is already the case before this patch. And it is
not 100% foolproof (you can make bogus objects using
`git hash-object`, for example), but it should be the
case for normal usage.
Therefore for any sequence of object additions, the
property will continue to hold.
2. If we remove objects from the repository, then we will
not remove a child object (like a blob) if an object
that refers to it is being kept. That is the part
implemented by this patch.
Note, however, that our reachability check and the
actual pruning are not atomic. So it _is_ still
possible to violate the property (e.g., an object
becomes referenced just as we are deleting it). This
patch is shooting for eliminating problems where the
mtimes of dependent objects differ by hours or days,
and one is dropped without the other. It does nothing
to help with short races.
Naively, the simplest way to implement this would be to add
all recent objects as tips to the reachability traversal.
However, this does not perform well. In a recently-packed
repository, all reachable objects will also be recent, and
therefore we have to look at each object twice. This patch
instead performs the reachability traversal, then follows up
with a second traversal for recent objects, skipping any
that have already been marked.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Haaris Mehmood
brian m. carlson
Martin Ågren
Junio C Hamano
Ævar Arnfjörð Bjarmason
Brandon Williams
Johannes Schindelin
Jeff King
René Scharfe
Alex Henrie
David Turner
Michael Haggerty