Conversion from unsigned char [40] to struct object_id continues.
* bc/object-id:
Documentation: update and rename api-sha1-array.txt
Rename sha1_array to oid_array
Convert sha1_array_for_each_unique and for_each_abbrev to object_id
Convert sha1_array_lookup to take struct object_id
Convert remaining callers of sha1_array_lookup to object_id
Make sha1_array_append take a struct object_id *
sha1-array: convert internal storage for struct sha1_array to object_id
builtin/pull: convert to struct object_id
submodule: convert check_for_new_submodule_commits to object_id
sha1_name: convert disambiguate_hint_fn to take object_id
sha1_name: convert struct disambiguate_state to object_id
test-sha1-array: convert most code to struct object_id
parse-options-cb: convert sha1_array_append caller to struct object_id
fsck: convert init_skiplist to struct object_id
builtin/receive-pack: convert portions to struct object_id
builtin/pull: convert portions to struct object_id
builtin/diff: convert to struct object_id
Convert GIT_SHA1_RAWSZ used for allocation to GIT_MAX_RAWSZ
Convert GIT_SHA1_HEXSZ used for allocation to GIT_MAX_HEXSZ
Define new hash-size constants for allocating memory
Code clean-up.
* jk/snprintf-cleanups:
daemon: use an argv_array to exec children
gc: replace local buffer with git_path
transport-helper: replace checked snprintf with xsnprintf
convert unchecked snprintf into xsnprintf
combine-diff: replace malloc/snprintf with xstrfmt
replace unchecked snprintf calls with heap buffers
receive-pack: print --pack-header directly into argv array
name-rev: replace static buffer with strbuf
create_branch: use xstrfmt for reflog message
create_branch: move msg setup closer to point of use
avoid using mksnpath for refs
avoid using fixed PATH_MAX buffers for refs
fetch: use heap buffer to format reflog
tag: use strbuf to format tag header
diff: avoid fixed-size buffer for patch-ids
odb_mkstemp: use git_path_buf
odb_mkstemp: write filename into strbuf
do not check odb_mkstemp return value for errors
Make sha1_array_for_each_unique take a callback using struct object_id.
Since one of these callbacks is an argument to for_each_abbrev, convert
those as well. Rename various functions, replacing "sha1" with "oid".
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A few commands that recently learned the "--recurse-submodule"
option misbehaved when started from a subdirectory of the
superproject.
* bw/recurse-submodules-relative-fix:
ls-files: fix bug when recursing with relative pathspec
ls-files: fix typo in variable name
grep: fix bug when recursing with relative pathspec
setup: allow for prefix to be passed to git commands
grep: fix help text typo
The odb_mkstemp() function expects the caller to provide a
fixed buffer to write the resulting tempfile name into. But
it creates the template using snprintf without checking the
return value. This means we could silently truncate the
filename.
In practice, it's unlikely that the truncation would end in
the template-pattern that mkstemp needs to open the file. So
we'd probably end up failing either way, unless the path was
specially crafted.
The simplest fix would be to notice the truncation and die.
However, we can observe that most callers immediately
xstrdup() the result anyway. So instead, let's switch to
using a strbuf, which is easier for them (and isn't a big
deal for the other 2 callers, who can just strbuf_release
when they're done with it).
Note that many of the callers used static buffers, but this
was purely to avoid putting a large buffer on the stack. We
never passed the static buffers out of the function, so
there's no complicated memory handling we need to change.
Signed-off-by: Jeff King <peff@peff.net>
The odb_mkstemp function does not return an error; it dies
on failure instead. But many of its callers compare the
resulting descriptor against -1 and die themselves.
Mostly this is just pointless, but it does raise a question
when looking at the callers: if they show the results of the
"template" buffer after a failure, what's in it? The answer
is: it doesn't matter, because it cannot happen.
So let's make that clear by removing the bogus error checks.
In bitmap_writer_finish(), we can drop the error-handling
code entirely. In the other two cases, it's shared with the
open() in another code path; we can just move the
error-check next to that open() call.
And while we're at it, let's flesh out the function's
docstring a bit to make the error behavior clear.
Signed-off-by: Jeff King <peff@peff.net>
The name-hash used for detecting paths that are different only in
cases (which matter on case insensitive filesystems) has been
optimized to take advantage of multi-threading when it makes sense.
* jh/memihash-opt:
name-hash: add test-lazy-init-name-hash to .gitignore
name-hash: add perf test for lazy_init_name_hash
name-hash: add test-lazy-init-name-hash
name-hash: perf improvement for lazy_init_name_hash
hashmap: document memihash_cont, hashmap_disallow_rehash api
hashmap: add disallow_rehash setting
hashmap: allow memihash computation to be continued
name-hash: specify initial size for istate.dir_hash table
Code clean-up with minor bugfixes.
* jk/prefix-filename:
bundle: use prefix_filename with bundle path
prefix_filename: simplify windows #ifdef
prefix_filename: return newly allocated string
prefix_filename: drop length parameter
prefix_filename: move docstring to header file
hash-object: fix buffer reuse with --path in a subdirectory
Since we will likely be introducing a new hash function at some point,
and that hash function might be longer than 20 bytes, use the constant
GIT_MAX_RAWSZ, which is designed to be suitable for allocations, instead
of GIT_SHA1_RAWSZ. This will ease the transition down the line by
distinguishing between places where we need to allocate memory suitable
for the largest hash from those where we need to handle the current
hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since we will want to transition to a new hash at some point in the
future, and that hash may be larger in size than 160 bits, introduce two
constants that can be used for allocating a sufficient amount of memory.
They can be increased to reflect the largest supported hash size.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The default location "~/.git-credential-cache/socket" for the
socket used to communicate with the credential-cache daemon has
been moved to "~/.cache/git/credential/socket".
* dl/credential-cache-socket-in-xdg-cache:
credential-cache: add tests for XDG functionality
credential-cache: use XDG_CACHE_HOME for socket
path.c: add xdg_cache_home
Add t/helper/test-lazy-init-name-hash.c test code
to demonstrate performance times for lazy_init_name_hash()
using the original single-threaded and the new multi-threaded
code paths.
Includes a --dump option to dump the created hashmaps to
stdout. You can use this to run both code paths and
confirm that they generate the same hashmaps.
Includes a --analyze option to analyze performance of both
code paths over a range of index sizes to help you find a
lower bound for the LAZY_THREAD_COST in name-hash.c.
For example, passing "-a 4000" will set "istate.cache_nr"
to 4000 and then try the multi-threaded code -- probably
giving 2 threads with 2000 entries each. It will then
run both the single-threaded (1x4000) and the multi-threaded
(2x2000) and compare the times. It will then repeat the
test with 8000, 12000, and etc. so that you can see the
cross over.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up.
* jk/pack-name-cleanups:
index-pack: make pointer-alias fallbacks safer
replace snprintf with odb_pack_name()
odb_pack_keep(): stop generating keepfile name
sha1_file.c: make pack-name helper globally accessible
move odb_* declarations out of git-compat-util.h
The prefix_filename() function returns a pointer to static
storage, which makes it easy to use dangerously. We already
fixed one buggy caller in hash-object recently, and the
calls in apply.c are suspicious (I didn't dig in enough to
confirm that there is a bug, but we call the function once
in apply_all_patches() and then again indirectly from
parse_chunk()).
Let's make it harder to get wrong by allocating the return
value. For simplicity, we'll do this even when the prefix is
empty (and we could just return the original file pointer).
That will cause us to allocate sometimes when we wouldn't
otherwise need to, but this function isn't called in
performance critical code-paths (and it already _might_
allocate on any given call, so a caller that cares about
performance is questionable anyway).
The downside is that the callers need to remember to free()
the result to avoid leaking. Most of them already used
xstrdup() on the result, so we know they are OK. The
remainder have been converted to use free() as appropriate.
I considered retaining a prefix_filename_unsafe() for cases
where we know the static lifetime is OK (and handling the
cleanup is awkward). This is only a handful of cases,
though, and it's not worth the mental energy in worrying
about whether the "unsafe" variant is OK to use in any
situation.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function takes the prefix as a ptr/len pair, but in
every caller the length is exactly strlen(ptr). Let's
simplify the interface and just take the string. This saves
callers specifying it (and in some cases handling a NULL
prefix).
In a handful of cases we had the length already without
calling strlen, so this is technically slower. But it's not
likely to matter (after all, if the prefix is non-empty
we'll allocate and copy it into a buffer anyway).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is a public function, so we should make its
documentation available near the declaration.
While we're at it, we can give a few details about how it
works.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The start-up sequence of "git" needs to figure out some configured
settings before it finds and set itself up in the location of the
repository and was quite messy due to its "chicken-and-egg" nature.
The code has been restructured.
* js/early-config:
setup.c: mention unresolved problems
t1309: document cases where we would want early config not to die()
setup_git_directory_gently_1(): avoid die()ing
t1309: test read_early_config()
read_early_config(): really discover .git/
read_early_config(): avoid .git/config hack when unneeded
setup: make read_early_config() reusable
setup: introduce the discover_git_directory() function
setup_git_directory_1(): avoid changing global state
setup: prepare setup_discovered_git_dir() for the root directory
setup_git_directory(): use is_dir_sep() helper
t7006: replace dubious test
Our source code has used the SHA1_HEADER cpp macro after "#include"
in the C code to switch among the SHA-1 implementations. Instead,
list the exact header file names and switch among implementations
using "#ifdef BLK_SHA1/#include "block-sha1/sha1.h"/.../#endif";
this helps some IDE tools.
* bc/sha1-header-selection-with-cpp-macros:
hash.h: move SHA-1 implementation selection into a header file
The experimental "split index" feature has gained a few
configuration variables to make it easier to use.
* cc/split-index-config: (22 commits)
Documentation/git-update-index: explain splitIndex.*
Documentation/config: add splitIndex.sharedIndexExpire
read-cache: use freshen_shared_index() in read_index_from()
read-cache: refactor read_index_from()
t1700: test shared index file expiration
read-cache: unlink old sharedindex files
config: add git_config_get_expiry() from gc.c
read-cache: touch shared index files when used
sha1_file: make check_and_freshen_file() non static
Documentation/config: add splitIndex.maxPercentChange
t1700: add tests for splitIndex.maxPercentChange
read-cache: regenerate shared index if necessary
config: add git_config_get_max_percent_split_change()
Documentation/git-update-index: talk about core.splitIndex config var
Documentation/config: add information for core.splitIndex
t1700: add tests for core.splitIndex
update-index: warn in case of split-index incoherency
read-cache: add and then use tweak_split_index()
split-index: add {add,remove}_split_index() functions
config: add git_config_get_split_index()
...
In a future patch child processes which act on submodules need a little
more context about the original command that was invoked. This patch
teaches git to use the prefix stored in `GIT_INTERNAL_TOPLEVEL_PREFIX`
instead of the prefix that was potentally found during the git directory
setup process.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The odb_pack_keep() function generates the name of a .keep
file and opens it. This has two problems:
1. It requires a fixed-size buffer to create the filename
and doesn't notice when the result is truncated.
2. Of the two callers, one sometimes wants to open a
filename it already has, which makes things awkward (it
has to do so manually, and skips the leading-directory
creation).
Instead, let's have odb_pack_keep() just open the file.
Generating the name isn't hard, and a future patch will
switch callers over to odb_pack_name() anyway.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We provide sha1_pack_name() and sha1_pack_index_name(), but
the more generic form (which takes its own strbuf and an
arbitrary extension) is only used to implement the other
two. Let's make it available, but clean up a few things:
1. Name it odb_pack_name(), as the original
sha1_get_pack_name() is long but not all that
descriptive.
2. Switch the strbuf argument to the beginning, so that it
matches similar path-building functions like
git_path_buf().
3. Clean up the out-dated docstring and move it to the
public declaration.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These functions were originally conceived as wrapper
functions similar to xmkstemp(). They were later moved by
463db9b10 (wrapper: move odb_* to environment.c,
2010-11-06). The more appropriate place for a declaration is
in cache.h.
While we're at it, let's add some basic docstrings.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many developers use functionality in their editors that allows for quick
syntax checks, including warning about questionable constructs. This
functionality allows rapid development with fewer errors. However, such
functionality generally does not allow the specification of
project-specific defines or command-line options.
Since the SHA1_HEADER include is not defined in such a case,
developers see spurious errors when using these tools. Furthermore,
there are known implementations of "cc" whose '#include' is unhappy
with this construct.
Instead of using SHA1_HEADER, create a hash.h header and use #if
and #elif to select the desired header. Have the Makefile pass an
appropriate option to help the header select the right implementation to
use.
[jc: make BLK_SHA1 the fallback default as discussed on list,
e.g. <20170314201424.vccij5z2ortq4a4o@sigill.intra.peff.net>; also
remove SHA1_HEADER and SHA1_HEADER_SQ that are no longer used].
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git branch @" created refs/heads/@ as a branch, and in general the
code that handled @{-1} and @{upstream} was a bit too loose in
disambiguating.
* jk/interpret-branch-name:
checkout: restrict @-expansions when finding branch
strbuf_check_ref_format(): expand only local branches
branch: restrict @-expansions when deleting
t3204: test git-branch @-expansion corner cases
interpret_branch_name: allow callers to restrict expansions
strbuf_branchname: add docstring
strbuf_branchname: drop return value
interpret_branch_name: move docstring to header file
interpret_branch_name(): handle auto-namelen for @{-1}
The pager configuration needs to be read early, possibly before
discovering any .git/ directory.
Let's not hide this function in pager.c, but make it available to other
callers.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We modified the setup_git_directory_gently_1() function earlier to make
it possible to discover the GIT_DIR without changing global state.
However, it is still a bit cumbersome to use if you only need to figure
out the (possibly absolute) path of the .git/ directory. Let's just
provide a convenient wrapper function with an easier signature that
*just* discovers the .git/ directory.
We will use it in a subsequent patch to fix the early config.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already have xdg_config_home to format paths relative to
XDG_CONFIG_HOME. Let's provide a similar function xdg_cache_home to do
the same for paths relative to XDG_CACHE_HOME.
Signed-off-by: Devin Lehmacher <lehmacdj@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git v2.12 was shipped with an embarrassing breakage where various
operations that verify paths given from the user stopped dying when
seeing an issue, and instead later triggering segfault.
* js/realpath-pathdup-fix:
real_pathdup(): fix callsites that wanted it to die on error
t1501: demonstrate NULL pointer access with invalid GIT_WORK_TREE
The "parse_config_key()" API function has been cleaned up.
* jk/parse-config-key-cleanup:
parse_hide_refs_config: tell parse_config_key we don't want a subsection
parse_config_key: allow matching single-level config
parse_config_key: use skip_prefix instead of starts_with
In 4ac9006f83 (real_path: have callers use real_pathdup and
strbuf_realpath, 2016-12-12), we changed the xstrdup(real_path())
pattern to use real_pathdup() directly.
The problem with this change is that real_path() calls
strbuf_realpath() with die_on_error = 1 while real_pathdup() calls
it with die_on_error = 0. Meaning that in cases where real_path()
causes Git to die() with an error message, real_pathdup() is silent
and returns NULL instead.
The callers, however, are ill-prepared for that change, as they expect
the return value to be non-NULL (and otherwise the function died
with an appropriate error message).
Fix this by extending real_pathdup()'s signature to accept the
die_on_error flag and simply pass it through to strbuf_realpath(),
and then adjust all callers after a careful audit whether they would
handle NULLs well.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The interpret_branch_name() function converts names like
@{-1} and @{upstream} into branch names. The expanded ref
names are not fully qualified, and may be outside of the
refs/heads/ namespace (e.g., "@" expands to "HEAD", and
"@{upstream}" is likely to be in "refs/remotes/").
This is OK for callers like dwim_ref() which are primarily
interested in resolving the resulting name, no matter where
it is. But callers like "git branch" treat the result as a
branch name in refs/heads/. When we expand to a ref outside
that namespace, the results are very confusing (e.g., "git
branch @" tries to create refs/heads/HEAD, which is
nonsense).
Callers can't know from the returned string how the
expansion happened (e.g., did the user really ask for a
branch named "HEAD", or did we do a bogus expansion?). One
fix would be to return some out-parameters describing the
types of expansion that occurred. This has the benefit that
the caller can generate precise error messages ("I
understood @{upstream} to mean origin/master, but that is a
remote tracking branch, so you cannot create it as a local
name").
However, out-parameters make the function interface somewhat
cumbersome. Instead, let's do the opposite: let the caller
tell us which elements to expand. That's easier to pass in,
and none of the callers give more precise error messages
than "@{upstream} isn't a valid branch name" anyway (which
should be sufficient).
The strbuf_branchname() function needs a similar parameter,
as most of the callers access interpret_branch_name()
through it.
We can break the callers down into two groups:
1. Callers that are happy with any kind of ref in the
result. We pass "0" here, so they continue to work
without restrictions. This includes merge_name(),
the reflog handling in add_pending_object_with_path(),
and substitute_branch_name(). This last is what powers
dwim_ref().
2. Callers that have funny corner cases (mostly in
git-branch and git-checkout). These need to make use of
the new parameter, but I've left them as "0" in this
patch, and will address them individually in follow-on
patches.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We generally put docstrings with function declarations,
because it's the callers who need to know how the function
works. Let's do so for interpret_branch_name().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function will be used in a following commit to get the expiration
time of the shared index files from the config, and it is generic
enough to be put in "config.c".
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function will be used in a commit soon, so let's make
it available globally.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new function will be used in a following commit to get the
value of the "splitIndex.maxPercentChange" config variable.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new function will be used in a following commit to know
if we want to use the split index feature or not.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The last caller of git_mkstemp() was removed in commit 6fec0a89
("verify_signed_buffer: use tempfile object", 16-06-2016). Since
the introduction of the 'tempfile' APIs, along with git_mkstemp_mode,
it is unlikely that new callers will materialize. Remove the dead
code.
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Deletion of a branch "foo/bar" could remove .git/refs/heads/foo
once there no longer is any other branch whose name begins with
"foo/", but we didn't do so so far. Now we do.
* mh/ref-remove-empty-directory: (23 commits)
files_transaction_commit(): clean up empty directories
try_remove_empty_parents(): teach to remove parents of reflogs, too
try_remove_empty_parents(): don't trash argument contents
try_remove_empty_parents(): rename parameter "name" -> "refname"
delete_ref_loose(): inline function
delete_ref_loose(): derive loose reference path from lock
log_ref_write_1(): inline function
log_ref_setup(): manage the name of the reflog file internally
log_ref_write_1(): don't depend on logfile argument
log_ref_setup(): pass the open file descriptor back to the caller
log_ref_setup(): improve robustness against races
log_ref_setup(): separate code for create vs non-create
log_ref_write(): inline function
rename_tmp_log(): improve error reporting
rename_tmp_log(): use raceproof_create_file()
lock_ref_sha1_basic(): use raceproof_create_file()
lock_ref_sha1_basic(): inline constant
raceproof_create_file(): new function
safe_create_leading_directories(): set errno on SCLD_EXISTS
safe_create_leading_directories_const(): preserve errno
...
The parse_config_key() function was introduced to make it
easier to match "section.subsection.key" variables. It also
handles the simpler "section.key", and the caller is
responsible for distinguishing the two from its
out-parameters.
Most callers who _only_ want "section.key" would just use a
strcmp(var, "section.key"), since there is no parsing
required. However, they may still use parse_config_key() if
their "section" variable isn't a constant (an example of
this is in parse_hide_refs_config).
Using the parse_config_key is a bit clunky, though:
const char *subsection;
int subsection_len;
const char *key;
if (!parse_config_key(var, section, &subsection, &subsection_len, &key) &&
!subsection) {
/* matched! */
}
Instead, let's treat a NULL subsection as an indication that
the caller does not expect one. That lets us write:
const char *key;
if (!parse_config_key(var, section, NULL, NULL, &key)) {
/* matched! */
}
Existing callers should be unaffected, as passing a NULL
subsection would currently segfault.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert each_loose_object_fn and each_packed_object_fn to take a pointer
to struct object_id. Update the various callbacks. Convert several
40-based constants to use GIT_SHA1_HEXSZ.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are places in the code where we would like to provide a struct
object_id *, yet read the hash directly from the pack. Provide an
nth_packed_object_oid function that is similar to the
nth_packed_object_sha1 function.
In order to avoid a potentially invalid cast, nth_packed_object_oid
provides a variable into which to store the value, which it returns on
success; on error, it returns NULL, as nth_packed_object_sha1 does.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a function, parse_oid_hex, which parses a hexadecimal object
ID and if successful, sets a pointer to just beyond the last character.
This allows for simpler, more robust parsing without needing to
hard-code integer values throughout the codebase.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "core.logAllRefUpdates" that used to be boolean has been
enhanced to take 'always' as well, to record ref updates to refs
other than the ones that are expected to be updated (i.e. branches,
remote-tracking branches and notes).
* cw/log-updates-for-all-refs-really:
doc: add note about ignoring '--no-create-reflog'
update-ref: add test cases for bare repository
refs: add option core.logAllRefUpdates = always
config: add markup to core.logAllRefUpdates doc
When a submodule "A", which has another submodule "B" nested within
it, is "absorbed" into the top-level superproject, the inner
submodule "B" used to be left in a strange state. The logic to
adjust the .git pointers in these submodules has been corrected.
* sb/submodule-recursive-absorb:
submodule absorbing: fix worktree/gitdir pointers recursively for non-moves
cache.h: expose the dying procedure for reading gitlinks
setup: add gentle version of resolve_git_dir
