Allow the default abbreviation length, which has historically been
7, to scale as the repository grows. The logic suggests to use 12
hexdigits for the Linux kernel, and 9 to 10 for Git itself.
* lt/abbrev-auto:
abbrev: auto size the default abbreviation
abbrev: prepare for new world order
abbrev: add FALLBACK_DEFAULT_ABBREV to prepare for auto sizing
A recently graduated topic regressed "git rev-list --header"
output, breaking "gitweb". This has been fixed.
* jk/diff-submodule-diff-inline:
rev-list: use hdr_termination instead of a always using a newline
When fetching from a remote that has many tags that are irrelevant
to branches we are following, we used to waste way too many cycles
when checking if the object pointed at by a tag (that we are not
going to fetch!) exists in our repository too carefully.
* jk/fetch-quick-tag-following:
fetch: use "quick" has_sha1_file for tag following
"git rebase" immediately after "git clone" failed to find the fork
point from the upstream.
* jk/merge-base-fork-point-without-reflog:
merge-base: handle --fork-point without reflog
"git ls-files" learned "--recurse-submodules" option that can be
used to get a listing of tracked files across submodules (i.e. this
only works with "--cached" option, not for listing untracked or
ignored files). This would be a useful tool to sit on the upstream
side of a pipe that is read with xargs to work on all working tree
files from the top-level superproject.
* bw/ls-files-recurse-submodules:
ls-files: add pathspec matching for submodules
ls-files: pass through safe options for --recurse-submodules
ls-files: optionally recurse into submodules
git: make super-prefix option
The require_clean_work_tree() helper was recreated in C when "git
pull" was rewritten from shell; the helper is now made available to
other callers in preparation for upcoming "rebase -i" work.
* js/libify-require-clean-work-tree:
wt-status: begin error messages with lower-case
wt-status: teach has_{unstaged,uncommitted}_changes() about submodules
wt-status: export also the has_un{staged,committed}_changes() functions
wt-status: make the require_clean_work_tree() function reusable
pull: make code more similar to the shell script again
pull: drop confusing prefix parameter of die_on_unclean_work_tree()
When adding support for prefixing output of log and other commands using
--line-prefix, commit 660e113ce1 ("graph: add support for
--line-prefix on all graph-aware output", 2016-08-31) accidentally
broke rev-list --header output.
In order to make the output appear with a line-prefix, the flow was
changed to always use the graph subsystem for display. Unfortunately
the graph flow in rev-list did not use info->hdr_termination as it was
assumed that graph output would never need to putput NULs.
Since we now always use the graph code in order to handle the case of
line-prefix, simply replace putchar('\n') with
putchar(info->hdr_termination) which will correct this issue.
Add a test for the --header case to make sure we don't break it in the
future.
Reported-by: Dennis Kaarsemaker <dennis@kaarsemaker.net>
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order for the receiving end of "git push" to inspect the
received history and decide to reject the push, the objects sent
from the sending end need to be made available to the hook and
the mechanism for the connectivity check, and this was done
traditionally by storing the objects in the receiving repository
and letting "git gc" to expire it. Instead, store the newly
received objects in a temporary area, and make them available by
reusing the alternate object store mechanism to them only while we
decide if we accept the check, and once we decide, either migrate
them to the repository or purge them immediately.
* jk/quarantine-received-objects:
tmp-objdir: do not migrate files starting with '.'
tmp-objdir: put quarantine information in the environment
receive-pack: quarantine objects until pre-receive accepts
tmp-objdir: introduce API for temporary object directories
check_connected: accept an env argument
Codepaths involved in interacting alternate object store have
been cleaned up.
* jk/alt-odb-cleanup:
alternates: use fspathcmp to detect duplicates
sha1_file: always allow relative paths to alternates
count-objects: report alternates via verbose mode
fill_sha1_file: write into a strbuf
alternates: store scratch buffer as strbuf
fill_sha1_file: write "boring" characters
alternates: use a separate scratch space
alternates: encapsulate alt->base munging
alternates: provide helper for allocating alternate
alternates: provide helper for adding to alternates list
link_alt_odb_entry: refactor string handling
link_alt_odb_entry: handle normalize_path errors
t5613: clarify "too deep" recursion tests
t5613: do not chdir in main process
t5613: whitespace/style cleanups
t5613: use test_must_fail
t5613: drop test_valid_repo function
t5613: drop reachable_via function
"git clone" of a local repository can be done at the filesystem
level, but the codepath did not check errors while copying and
adjusting the file that lists alternate object stores.
* jk/clone-copy-alternates-fix:
clone: detect errors in normalize_path_copy
When we auto-follow tags in a fetch, we look at all of the
tags advertised by the remote and fetch ones where we don't
already have the tag, but we do have the object it peels to.
This involves a lot of calls to has_sha1_file(), some of
which we can reasonably expect to fail. Since 45e8a74
(has_sha1_file: re-check pack directory before giving up,
2013-08-30), this may cause many calls to
reprepare_packed_git(), which is potentially expensive.
This has gone unnoticed for several years because it
requires a fairly unique setup to matter:
1. You need to have a lot of packs on the client side to
make reprepare_packed_git() expensive (the most
expensive part is finding duplicates in an unsorted
list, which is currently quadratic).
2. You need a large number of tag refs on the server side
that are candidates for auto-following (i.e., that the
client doesn't have). Each one triggers a re-read of
the pack directory.
3. Under normal circumstances, the client would
auto-follow those tags and after one large fetch, (2)
would no longer be true. But if those tags point to
history which is disconnected from what the client
otherwise fetches, then it will never auto-follow, and
those candidates will impact it on every fetch.
So when all three are true, each fetch pays an extra
O(nr_tags * nr_packs^2) cost, mostly in string comparisons
on the pack names. This was exacerbated by 47bf4b0
(prepare_packed_git_one: refactor duplicate-pack check,
2014-06-30) which uses a slightly more expensive string
check, under the assumption that the duplicate check doesn't
happen very often (and it shouldn't; the real problem here
is how often we are calling reprepare_packed_git()).
This patch teaches fetch to use HAS_SHA1_QUICK to sacrifice
accuracy for speed, in cases where we might be racy with a
simultaneous repack. This is similar to the fix in 0eeb077
(index-pack: avoid excessive re-reading of pack directory,
2015-06-09). As with that case, it's OK for has_sha1_file()
occasionally say "no I don't have it" when we do, because
the worst case is not a corruption, but simply that we may
fail to auto-follow a tag that points to it.
Here are results from the included perf script, which sets
up a situation similar to the one described above:
Test HEAD^ HEAD
----------------------------------------------------------
5550.4: fetch 11.21(10.42+0.78) 0.08(0.04+0.02) -99.3%
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The --fork-point option looks in the reflog to try to find
where a derived branch forked from a base branch. However,
if the reflog for the base branch is totally empty (as it
commonly is right after cloning, which does not write a
reflog entry), then our for_each_reflog call will not find
any entries, and we will come up with no merge base, even
though there may be one with the current tip of the base.
We can fix this by just adding the current tip to
our list of collected entries.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The <tree-ish> parameter is actually optional (see man page).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is a common mistake to say "git blame --reverse OLD path",
expecting that the command line is dwimmed as if asking how lines
in path in an old revision OLD have survived up to the current
commit.
* jc/blame-reverse:
blame: dwim "blame --reverse OLD" as "blame --reverse OLD.."
blame: improve diagnosis for "--reverse NEW"
The existing "git fetch --depth=<n>" option was hard to use
correctly when making the history of an existing shallow clone
deeper. A new option, "--deepen=<n>", has been added to make this
easier to use. "git clone" also learned "--shallow-since=<date>"
and "--shallow-exclude=<tag>" options to make it easier to specify
"I am interested only in the recent N months worth of history" and
"Give me only the history since that version".
* nd/shallow-deepen: (27 commits)
fetch, upload-pack: --deepen=N extends shallow boundary by N commits
upload-pack: add get_reachable_list()
upload-pack: split check_unreachable() in two, prep for get_reachable_list()
t5500, t5539: tests for shallow depth excluding a ref
clone: define shallow clone boundary with --shallow-exclude
fetch: define shallow boundary with --shallow-exclude
upload-pack: support define shallow boundary by excluding revisions
refs: add expand_ref()
t5500, t5539: tests for shallow depth since a specific date
clone: define shallow clone boundary based on time with --shallow-since
fetch: define shallow boundary with --shallow-since
upload-pack: add deepen-since to cut shallow repos based on time
shallow.c: implement a generic shallow boundary finder based on rev-list
fetch-pack: use a separate flag for fetch in deepening mode
fetch-pack.c: mark strings for translating
fetch-pack: use a common function for verbose printing
fetch-pack: use skip_prefix() instead of starts_with()
upload-pack: move rev-list code out of check_non_tip()
upload-pack: make check_non_tip() clean things up on error
upload-pack: tighten number parsing at "deepen" lines
...
"git pack-objects" in a repository with many packfiles used to
spend a lot of time looking for/at objects in them; the accesses to
the packfiles are now optimized by checking the most-recently-used
packfile first.
* jk/pack-objects-optim-mru:
pack-objects: use mru list when iterating over packs
pack-objects: break delta cycles before delta-search phase
sha1_file: make packed_object_info public
provide an initializer for "struct object_info"
We call "qsort(array, nelem, sizeof(array[0]), fn)", and most of
the time third parameter is redundant. A new QSORT() macro lets us
omit it.
* rs/qsort:
show-branch: use QSORT
use QSORT, part 2
coccicheck: use --all-includes by default
remove unnecessary check before QSORT
use QSORT
add QSORT
When a client pushes objects to us, index-pack checks the
objects themselves and then installs them into place. If we
then reject the push due to a pre-receive hook, we cannot
just delete the packfile; other processes may be depending
on it. We have to do a normal reachability check at this
point via `git gc`.
But such objects may hang around for weeks due to the
gc.pruneExpire grace period. And worse, during that time
they may be exploded from the pack into inefficient loose
objects.
Instead, this patch teaches receive-pack to put the new
objects into a "quarantine" temporary directory. We make
these objects available to the connectivity check and to the
pre-receive hook, and then install them into place only if
it is successful (and otherwise remove them as tempfiles).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On a case-insensitive filesystem, we should realize that
"a/objects" and "A/objects" are the same path. We already
use fspathcmp() to check against the main object directory,
but until recently we couldn't use it for comparing against
other alternates (because their paths were not
NUL-terminated strings). But now we can, so let's do so.
Note that we also need to adjust count-objects to load the
config, so that it can see the setting of core.ignorecase
(this is required by the test, but is also a general bugfix
for users of count-objects).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There's no way to get the list of alternates that git
computes internally; our tests only infer it based on which
objects are available. In addition to testing, knowing this
list may be helpful for somebody debugging their alternates
setup.
Let's add it to the "count-objects -v" output. We could give
it a separate flag, but there's not really any need.
"count-objects -v" is already a debugging catch-all for the
object database, its output is easily extensible to new data
items, and printing the alternates is not expensive (we
already had to find them to count the objects).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The alternate_object_database struct uses a single buffer
both for storing the path to the alternate, and as a scratch
buffer for forming object names. This is efficient (since
otherwise we'd end up storing the path twice), but it makes
life hard for callers who just want to know the path to the
alternate. They have to remember to stop reading after
"alt->name - alt->base" bytes, and to subtract one for the
trailing '/'.
It would be much simpler if they could simply access a
NUL-terminated path string. We could encapsulate this in a
function which puts a NUL in the scratch buffer and returns
the string, but that opens up questions about the lifetime
of the result. The first time another caller uses the
alternate, the scratch buffer may get other data tacked onto
it.
Let's instead just store the root path separately from the
scratch buffer. There aren't enough alternates being stored
for the duplicated data to matter for performance, and this
keeps things simple and safe for the callers.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pathspecs can be a bit tricky when trying to apply them to submodules.
The main challenge is that the pathspecs will be with respect to the
superproject and not with respect to paths in the submodule. The
approach this patch takes is to pass in the identical pathspec from the
superproject to the submodule in addition to the submodule-prefix, which
is the path from the root of the superproject to the submodule, and then
we can compare an entry in the submodule prepended with the
submodule-prefix to the pathspec in order to determine if there is a
match.
This patch also permits the pathspec logic to perform a prefix match against
submodules since a pathspec could refer to a file inside of a submodule.
Due to limitations in the wildmatch logic, a prefix match is only done
literally. If any wildcard character is encountered we'll simply punt
and produce a false positive match. More accurate matching will be done
once inside the submodule. This is due to the superproject not knowing
what files could exist in the submodule.
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pass through some known-safe options when recursing into submodules.
(--cached, -v, -t, -z, --debug, --eol)
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow ls-files to recognize submodules in order to retrieve a list of
files from a repository's submodules. This is done by forking off a
process to recursively call ls-files on all submodules. Use top-level
--super-prefix option to pass a path to the submodule which it can
use to prepend to output or pathspec matching logic.
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sometimes we are *actually* interested in those changes... For
example when an interactive rebase wants to continue with a staged
submodule update.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function used by "git pull" to stop the user when the working
tree has changes is useful in other places.
Let's move it into a more prominent (and into an actually reusable)
spot: wt-status.[ch].
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When converting the pull command to a builtin, the
require_clean_work_tree() function was renamed and the pull-specific
parts hard-coded.
This makes it impossible to reuse the code, so let's modify the code to
make it more similar to the original shell script again.
Note: when the hint "Please commit or stash them" was introduced first,
Git did not have the convention of continuing error messages in lower
case, but now we do have that convention, therefore we reintroduce this
hint down-cased, obeying said convention.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In cmd_pull(), when verifying that there are no changes preventing a
rebasing pull, we diligently pass the prefix parameter to the
die_on_unclean_work_tree() function which in turn diligently passes it
to the has_unstaged_changes() and has_uncommitted_changes() functions.
The casual reader might now be curious (as this developer was) whether
that means that calling `git pull --rebase` in a subdirectory will
ignore unstaged changes in other parts of the working directory. And be
puzzled that `git pull --rebase` (correctly) complains about those
changes outside of the current directory.
The puzzle is easily resolved: while we take pains to pass around the
prefix and even pass it to init_revisions(), the fact that no paths are
passed to init_revisions() ensures that the prefix is simply ignored.
That, combined with the fact that we will *always* want a *full* working
directory check before running a rebasing pull, is reason enough to
simply do away with the actual prefix parameter and to pass NULL
instead, as if we were running this from the top-level working directory
anyway.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up with help from coccinelle tool continues.
* rs/cocci:
coccicheck: make transformation for strbuf_addf(sb, "...") more precise
use strbuf_add_unique_abbrev() for adding short hashes, part 2
use strbuf_addstr() instead of strbuf_addf() with "%s", part 2
gitignore: ignore output files of coccicheck make target
Almost everybody uses DEFAULT_ABBREV to refer to the default
setting for the abbreviation, but "git blame" peeked into
underlying variable bypassing the macro for no good reason.
* jc/blame-abbrev:
blame: use DEFAULT_ABBREV macro
"git log rev^..rev" is an often-used revision range specification
to show what was done on a side branch merged at rev. This has
gained a short-hand "rev^-1". In general "rev^-$n" is the same as
"^rev^$n rev", i.e. what has happened on other branches while the
history leading to nth parent was looking the other way.
* vn/revision-shorthand-for-side-branch-log:
revision: new rev^-n shorthand for rev^n..rev
When given an abbreviated object name that is not (or more
realistically, "no longer") unique, we gave a fatal error
"ambiguous argument". This error is now accompanied by hints that
lists the objects that begins with the given prefix. During the
course of development of this new feature, numerous minor bugs were
uncovered and corrected, the most notable one of which is that we
gave "short SHA1 xxxx is ambiguous." twice without good reason.
* jk/ambiguous-short-object-names:
get_short_sha1: make default disambiguation configurable
get_short_sha1: list ambiguous objects on error
for_each_abbrev: drop duplicate objects
sha1_array: let callbacks interrupt iteration
get_short_sha1: mark ambiguity error for translation
get_short_sha1: NUL-terminate hex prefix
get_short_sha1: refactor init of disambiguation code
get_short_sha1: parse tags when looking for treeish
get_sha1: propagate flags to child functions
get_sha1: avoid repeating ourselves via ONLY_TO_DIE
get_sha1: detect buggy calls with multiple disambiguators
When we are copying the alternates from the source
repository, if we find a relative path that is too deep for
the source (e.g., "../../../objects" from "/repo.git/objects"),
then normalize_path_copy will report an error and leave
trash in the buffer, which we will add to our new alternates
file. Instead, let's detect the error, print a warning, and
skip copying that alternate.
There's no need to die. The relative path is probably just
broken cruft in the source repo. If it turns out to have
been important for accessing some objects, we rely on other
parts of the clone to detect that, just as they would with a
missing object in the source repo itself (though note that
clones with "-s" are inherently local, which may do fewer
object-quality checks in the first place).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git init" tried to record core.worktree in the repository's
'config' file when GIT_WORK_TREE environment variable was set and
it was different from where GIT_DIR appears as ".git" at its top,
but the logic was faulty when .git is a "gitdir:" file that points
at the real place, causing trouble in working trees that are
managed by "git worktree". This has been corrected.
* nd/init-core-worktree-in-multi-worktree-world:
init: kill git_link variable
init: do not set unnecessary core.worktree
init: kill set_git_dir_init()
init: call set_git_dir_init() from within init_db()
init: correct re-initialization from a linked worktree
The code that sets custom abbreviation length, in response to
command line argument, often does something like this:
if (skip_prefix(arg, "--abbrev=", &arg))
abbrev = atoi(arg);
else if (!strcmp("--abbrev", &arg))
abbrev = DEFAULT_ABBREV;
/* make the value sane */
if (abbrev < 0 || 40 < abbrev)
abbrev = ... some sane value ...
However, it is pointless to sanity-check and tweak the value
obtained from DEFAULT_ABBREV. We are going to allow it to be
initially set to -1 to signal that the default abbreviation length
must be auto sized upon the first request to abbreviate, based on
the number of objects in the repository, and when that happens,
rejecting or tweaking a negative value to a "saner" one will
negatively interfere with the auto sizing. The codepaths for
git rev-parse --short <object>
git diff --raw --abbrev
do exactly that; allow them to pass possibly negative abbrevs
intact, that will come from DEFAULT_ABBREV in the future.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We'll be introducing a new way to decide the default abbreviation
length by initialising DEFAULT_ABBREV to -1 to signal the first call
to "find unique abbreviation" codepath to compute a reasonable value
based on the number of objects we have to avoid collisions.
We have long relied on DEFAULT_ABBREV being a positive concrete
value that is used as the abbreviation length when no extra
configuration or command line option has overridden it. Some
codepaths wants to use such a positive concrete default value
even before making their first request to actually trigger the
computation for the auto sized default.
Introduce FALLBACK_DEFAULT_ABBREV and use it to the code that
attempts to align the report from "git fetch". For now, this
macro is also used to initialize the default_abbrev variable,
but the auto-sizing code will use -1 and then use the value of
FALLBACK_DEFAULT_ABBREV as the starting point of auto-sizing.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Shorten the code by using QSORT instead of calling qsort(3) directly,
as the former determines the element size automatically and checks if
there are at least two elements to sort already.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert two more qsort(3) calls to QSORT to reduce code size and for
better safety and consistency.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git worktree", even though it used the default_abbrev setting that
ought to be affected by core.abbrev configuration variable, ignored
the variable setting. The command has been taught to read the
default set of configuration variables to correct this.
* jc/worktree-config:
worktree: honor configuration variables
Add a semantic patch for removing checks similar to the one that QSORT
already does internally and apply it to the code base.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT. The resulting code is
shorter and supports empty arrays with NULL pointers.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This does not make any practical difference in today's code, but
everybody else accesses the default abbreviation length via the
DEFAULT_ABBREV macro. Make sure this oddball codepath does not
stray from the convention.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace uses of strbuf_addf() for adding strings with more lightweight
strbuf_addstr() calls. This is shorter and makes the intent clearer.
bc57b9c0cc already converted three cases,
this patch covers two more.
A semantic patch for Coccinelle is included for easier checking for
new cases that might be introduced in the future.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git log rev^..rev" is commonly used to show all work done on and merged
from a side branch. This patch introduces a shorthand "rev^-" for this
and additionally allows "rev^-$n" to mean "reachable from rev, excluding
what is reachable from the nth parent of rev". For example, for a
two-parent merge, you can use rev^-2 to get the set of commits which were
made to the main branch while the topic branch was prepared.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The command accesses default_abbrev (defined in environment.c and is
updated via core.abbrev configuration), but never makes any call to
git_config(). The output from "worktree list" ignores the abbrev
setting for this reason.
Make a call to git_config() to read the default set of configuration
variables at the beginning of the command.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git clone --recurse-submodules" lost the progress eye-candy in
recent update, which has been corrected.
* jk/clone-recursive-progress:
clone: pass --progress decision to recursive submodules
"git add --chmod=+x <pathspec>" added recently only toggled the
executable bit for paths that are either new or modified. This has
been corrected to flip the executable bit for all paths that match
the given pathspec.
* tg/add-chmod+x-fix:
t3700-add: do not check working tree file mode without POSIXPERM
t3700-add: create subdirectory gently
add: modify already added files when --chmod is given
read-cache: introduce chmod_index_entry
update-index: add test for chmod flags
