When a user checks out the upstream branch of HEAD, the upstream branch
not being a local branch, and then runs "git status", like this:
git clone $URL client
cd client
git checkout @{u}
git status
no status is printed, but instead an error message:
fatal: HEAD does not point to a branch
(This error message when running "git branch" persists even after
checking out other things - it only stops after checking out a branch.)
This is because "git status" reads the reflog when determining the "HEAD
detached" message, and thus attempts to DWIM "@{u}", but that doesn't
work because HEAD no longer points to a branch.
Therefore, when calculating the status of a worktree, tolerate dangling
marks. This is done by adding an additional parameter to
dwim_ref() and repo_dwim_ref().
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the codebase, there are many options which use OPTION_CALLBACK in a
plain ol' struct definition. However, we have the OPT_CALLBACK and
OPT_CALLBACK_F macros which are meant to abstract these plain struct
definitions away. These macros are useful as they semantically signal to
developers that these are just normal callback option with nothing fancy
happening.
Replace plain struct definitions of OPTION_CALLBACK with OPT_CALLBACK or
OPT_CALLBACK_F where applicable. The heavy lifting was done using the
following (disgusting) shell script:
#!/bin/sh
do_replacement () {
tr '\n' '\r' |
sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\s*0,\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK(\1,\2,\3,\4,\5,\6)/g' |
sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK_F(\1,\2,\3,\4,\5,\6,\7)/g' |
tr '\r' '\n'
}
for f in $(git ls-files \*.c)
do
do_replacement <"$f" >"$f.tmp"
mv "$f.tmp" "$f"
done
The result was manually inspected and then reformatted to match the
style of the surrounding code. Finally, using
`git grep OPTION_CALLBACK \*.c`, leftover results which were not handled
by the script were manually transformed.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pass the commit, and if we have it, the ref to the filters when we
perform a checkout. This should only be the case when we invoke git
reset --hard; the metadata will be unused otherwise.
Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 2f328c3d ("reset $sha1 $pathspec: require $sha1 only to be
treeish", 2013-01-14), we allowed "git reset $object -- $path" to reset
individual paths that match the pathspec to take the blob from a tree
object, not necessarily a commit, while the form to reset the tip of the
current branch to some other commit still must be given a commit.
Like resetting with paths, "git reset --patch" does not update HEAD, and
need not require a commit. The path-filtered form, "git reset --patch
$object -- $pathspec", has accepted a tree-ish since 2f328c3d.
"git reset --patch" is documented as accepting a <tree-ish> since
bf44142f ("reset: update documentation to require only tree-ish with
paths", 2013-01-16). Documentation changes are not required.
Loosen the restriction that requires a commit for the unfiltered "git
reset --patch $object".
Signed-off-by: Nika Layzell <nika@thelayzells.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Decisions taken for simplicity:
1) For now, `--pathspec-from-file` is declared incompatible with
`--patch`, even when <file> is not `stdin`. Such use case it not
really expected. Also, it is harder to support in `git commit`, so
I decided to make it incompatible in all places.
2) It is not allowed to pass pathspec in both args and file.
Co-authored-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git add` shows an example of good writing, follow it.
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While at there, clean up the_repo usage in builtin/merge-tree.c a tiny
bit.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After a successful switch, if a merge, cherry-pick or revert is ongoing,
it is canceled. This behavior has been with us from the very early
beginning, soon after git-merge was created but never actually
documented [1]. It may be a good idea to be transparent and tell the
user if some operation is canceled.
I consider this a better way of telling the user than just adding a
sentence or two in git-checkout.txt, which will be mostly ignored
anyway.
PS. Originally I wanted to print more details like
warning: cancelling an in-progress merge from <SHA-1>
which may allow some level of undo if the user wants to. But that seems
a lot more work. Perhaps it can be improved later if people still want
that.
[1] ... and I will try not to argue whether it is a sensible behavior.
There is some more discussion here if people are interested:
CACsJy8Axa5WsLSjiscjnxVK6jQHkfs-gH959=YtUvQkWriAk5w@mail.gmail.com
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a post-index-change hook that is invoked after the index is written in
do_write_locked_index().
This hook is meant primarily for notification, and cannot affect
the outcome of git commands that trigger the index write.
The hook is passed a flag to indicate whether the working directory was
updated or not and a flag indicating if a skip-worktree bit could have
changed. These flags enable the hook to optimize its response to the
index change notification.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
By default, index compat macros are off from now on, because they
could hide the_index dependency.
Only those in builtin can use it.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This case is more interesting than other boring "remove the_repo"
commits because while we need access to the object database, we cannot
simply use r->index because unpack-trees.c can operate on a temporary
index, not $GIT_DIR/index. Ideally we should be able to pass an object
database to lookup_tree() but that ship has sailed.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
refresh_index() is done after a reset command as an optimization. Because
it can be an expensive call, warn the user if it takes more than 2 seconds
and tell them how to avoid it using the --quiet command line option or
reset.quiet config setting.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a reset.quiet config setting that sets the default value of the --quiet
flag when running the reset command. This enables users to change the
default behavior to take advantage of the performance advantages of
avoiding the scan for unstaged changes after reset. Defaults to false.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When git reset is run with the --quiet flag, don't bother finding any
additional unstaged changes as they won't be output anyway. This speeds up
the git reset command by avoiding having to lstat() every file looking for
changes that aren't going to be reported anyway.
The savings can be significant. In a repo on Windows with 200K files
"git reset" drops from 7.16 seconds to 0.32 seconds for a savings of 96%.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff and textconv code has so widespread use that it's hard to simply
update their api and all call sites at once because it would result in
a big patch. For now reduce the_index references to two places:
diff_setup() and fill_textconv().
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It has been observed that the time spent loading an index with a large
number of entries is partly dominated by malloc() calls. This change
is in preparation for using memory pools to reduce the number of
malloc() calls made to allocate cahce entries when loading an index.
Add an API to allocate and discard cache entries, abstracting the
details of managing the memory backing the cache entries. This commit
does actually change how memory is managed - this will be done in a
later commit in the series.
This change makes the distinction between cache entries that are
associated with an index and cache entries that are not associated with
an index. A main use of cache entries is with an index, and we can
optimize the memory management around this. We still have other cases
where a cache entry is not persisted with an index, and so we need to
handle the "transient" use case as well.
To keep the congnitive overhead of managing the cache entries, there
will only be a single discard function. This means there must be enough
information kept with the cache entry so that we know how to discard
them.
A summary of the main functions in the API is:
make_cache_entry: create cache entry for use in an index. Uses specified
parameters to populate cache_entry fields.
make_empty_cache_entry: Create an empty cache entry for use in an index.
Returns cache entry with empty fields.
make_transient_cache_entry: create cache entry that is not used in an
index. Uses specified parameters to populate
cache_entry fields.
make_empty_transient_cache_entry: create cache entry that is not used in
an index. Returns cache entry with
empty fields.
discard_cache_entry: A single function that knows how to discard a cache
entry regardless of how it was allocated.
Signed-off-by: Jameson Miller <jamill@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a repository argument to allow callers of lookup_commit_reference
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.
As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Migrate all git_path_* functions that are defined in path.c to take a
repository argument. Unlike other patches in this series, do not use the
#define trick, as we rewrite the whole function, which is rather small.
This doesn't migrate all the functions, as other builtins have their own
local path functions defined using GIT_PATH_FUNC. So keep that macro
around to serve the other locations.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the last use of EMPTY_TREE_SHA1_BIN to use a direct copy from
the_hash_algo->empty_tree to avoid a dependency on a given hash
algorithm.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert find_unique_abbrev and find_unique_abbrev_r to each take a
pointer to struct object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset --hard currently uses its own logic for printing the first line of
the commit message in its output. Instead of just using the first line,
use the pretty machinery to create the output.
In addition to the easier to follow code, this makes the output more
consistent with other commands that print the title of the commit, such
as 'git commit --oneline' or 'git checkout', which both use
'pp_commit_easy()' with the CMIT_FMT_ONELINE modifier.
It is a slight change of the output if the second line of the commit
message is not a blank line, i.e. if the commit message is
foo
bar
previously we would print "HEAD is now at 000000 foo", while after
this change we print "HEAD is now at 000000 foo bar", same as 'git log
--oneline' shows "000000 foo bar".
So this does make the output more consistent with other commands, and
'reset' is a porcelain command, so nobody should be parsing the output
in scripts.
The current behaviour dates back to 0e5a7faa3a ("Make "git reset" a
builtin.", 2007-09-11), so I assume (without digging into the old
codebase too much) that the logic was implemented because there was
no convenience function such as 'pp_commit_easy' that would do this
already.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create header for pretty.c to make formatting interface more structured.
This is a middle point, this file would be merged further with other
files which contain formatting stuff.
Signed-off-by: Olga Telezhnaia <olyatelezhnaya@gmail.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the `DIFF_OPT_SET` macro and instead set the flags directly.
This conversion is done using the following semantic patch:
@@
expression E;
identifier fld;
@@
- DIFF_OPT_SET(&E, fld)
+ E.flags.fld = 1
@@
type T;
T *ptr;
identifier fld;
@@
- DIFF_OPT_SET(ptr, fld)
+ ptr->flags.fld = 1
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of explicitly setting the 'DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG'
flag, use the 'DIFF_OPT_SET' macro.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert update_ref, refs_update_ref, and write_pseudoref to use struct
object_id. Update the existing callers as well. Remove update_ref_oid,
as it is no longer needed.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert delete_ref and refs_delete_ref to take a pointer to struct
object_id. Update the documentation accordingly, including referring to
null_oid in lowercase, as it is not a #define constant.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We read the tree objects with fill_tree_descriptor(), but
never actually free the resulting buffers, causing a memory
leak. This isn't a huge deal because we call this code at
most twice per program invocation. But it does potentially
double our heap usage if you have large root trees. Let's
free the trees before returning.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Depending on whether we're in --keep mode, git-reset may
feed one or two trees to unpack_trees(). We start a counter
at "1" and then increment it to "2" only for the two-tree
case. But that means we must always subtract one to find the
correct array slot to fill with each descriptor.
Instead, let's start at "0" and just increment our counter
after adding each tree. This skips the extra subtraction,
and will make things much easier when we start to actually
free our tree buffers.
While we're at it, let's make the first allocation use the
slot at "desc + nr", too, even though we know "nr" is 0 at
that point. It makes the two fill_tree_descriptor() calls
consistent (always "desc + nr", followed by always
incrementing "nr").
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that it's safe to declare a "struct lock_file" on the
stack, we can do so (and avoid an intentional leak). These
leaks were found by running t0000 and t0001 under valgrind
(though certainly other similar leaks exist and just don't
happen to be exercised by those tests).
Initializing the lock_file's inner tempfile with NULL is not
strictly necessary in these cases, but it's a good practice
to model. It means that if we were to call a function like
rollback_lock_file() on a lock that was never taken in the
first place, it becomes a quiet noop (rather than undefined
behavior).
Likewise, it's always safe to rollback_lock_file() on a file
that has already been committed or deleted, since that
operation is a noop on an inactive lockfile (and that's why
the case in config.c can drop the "if (lock)" check as we
move away from using a pointer).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All callers of fill_tree_descriptor() have been converted to object_id
already, so convert that function as well. As a nice side-effect we get
rid of NULL checks in tree-diff.c, as fill_tree_descriptor() already
does them for us.
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the submodule-config subsystem can lazily read the gitmodules
file we no longer need to explicitly pre-read the gitmodules by calling
'gitmodules_config()' so let's remove it.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit aee9c7d65 (Submodules: Add the new "ignore" config option for
diff and status) introduced the ignore configuration option for
submodules so that configured submodules could be omitted from the
status and diff commands. Because this flag is respected in the diff
machinery it has the unintended consequence of potentially prohibiting
users from adding or resetting a submodule, even when a path to the
submodule is explicitly given.
Ensure that submodules can be added or set, even if they are configured
to be ignored, by setting the `DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG` diff
flag.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
Any command that understands '--recurse-submodules' can have its
default changed to true, by setting the new 'submodule.recurse'
option.
This patch includes read-tree/checkout/reset for working tree
manipulating commands. Later patches will cover other commands.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The callback function is essentially duplicated 3 times. Remove all
of them and offer a new callback function, that lives in submodule.c
By putting the callback function there, we no longer need the function
'set_config_update_recurse_submodules', nor duplicate the global variable
in each builtin as well as submodule.c
In the three builtins we have different 2 ways how to load the .gitmodules
and config file, which are slightly different. git-checkout has to load
the submodule config all the time due to 23b4c7bcc5 (checkout: Use
submodule.*.ignore settings from .git/config and .gitmodules, 2010-08-28)
git-reset and git-read-tree do not respect these diff settings, so loading
the submodule configuration is optional. Also put that into submodule.c
for code deduplication.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The command line option for '--recurse-submodules' is implemented
using an OPTION_CALLBACK, which takes both the callback (that sets
the file static global variable) as well as passes the same file
static global variable to the option parsing machinery to assign it.
This is fixed in this commit by passing NULL as the variable. The
callback sets it instead
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since (ae8d08242 pathspec: pass directory indicator to
match_pathspec_item()) the path matching logic has been able to cope
with submodules without needing to strip off a trailing slash if a path
refers to a submodule.
Since stripping the slash is no longer necessary, remove the
PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP flag.
Signed-off-by: Brandon Williams <bmwill@google.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>
This is needed to convert parse_tree_indirect.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
git-reset is yet another working tree manipulator, which should
be taught about submodules.
When a user uses git-reset and requests to recurse into submodules,
this will reset the submodules to the object name as recorded in the
superproject, detaching the HEADs.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the current branch is renamed with 'git branch -m/-M' or deleted
with 'git update-ref -m<msg> -d', the event is recorded in HEAD's log
with an empty message. In preparation for adding a more meaningful
message to HEAD's log in these cases, update delete_ref() to take a
message argument and pass it along to ref_transaction_delete().
Modify all callers to pass NULL for the new message argument; no
change in behavior is intended.
Note that this is relevant for HEAD's log but not for the deleted
ref's log, which is currently deleted along with the ref. Even if it
were not, an entry for the deletion wouldn't be present in the deleted
ref's log. files_transaction_commit() writes to the log if
REF_NEEDS_COMMIT or REF_LOG_ONLY are set, but lock_ref_for_update()
doesn't set REF_NEEDS_COMMIT for the deleted ref because REF_DELETING
is set. In contrast, the update for HEAD has REF_LOG_ONLY set by
split_head_update(), resulting in the deletion being logged.
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Callers of the hold_locked_index() function pass 0 when they want to
prepare to write a new version of the index file without wishing to
die or emit an error message when the request fails (e.g. somebody
else already held the lock), and pass 1 when they want the call to
die upon failure.
This option is called LOCK_DIE_ON_ERROR by the underlying lockfile
API, and the hold_locked_index() function translates the paramter to
LOCK_DIE_ON_ERROR when calling the hold_lock_file_for_update().
Replace these hardcoded '1' with LOCK_DIE_ON_ERROR and stop
translating. Callers other than the ones that are replaced with
this change pass '0' to the function; no behaviour change is
intended with this patch.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
Among the callers of hold_locked_index() that passes 0:
- diff.c::refresh_index_quietly() at the end of "git diff" is an
opportunistic update; it leaks the lockfile structure but it is
just before the program exits and nobody should care.
- builtin/describe.c::cmd_describe(),
builtin/commit.c::cmd_status(),
sequencer.c::read_and_refresh_cache() are all opportunistic
updates and they are OK.
- builtin/update-index.c::cmd_update_index() takes a lock upfront
but we may end up not needing to update the index (i.e. the
entries may be fully up-to-date), in which case we do not need to
issue an error upon failure to acquire the lock. We do diagnose
and die if we indeed need to update, so it is OK.
- wt-status.c::require_clean_work_tree() IS BUGGY. It asks
silence, does not check the returned value. Compare with
callsites like cmd_describe() and cmd_status() to notice that it
is wrong to call update_index_if_able() unconditionally.
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>