In preparation for implementing narrow/partial clone, the object
walking machinery has been taught a way to tell it to "filter" some
objects from enumeration.
* jh/object-filtering:
rev-list: support --no-filter argument
list-objects-filter-options: support --no-filter
list-objects-filter-options: fix 'keword' typo in comment
pack-objects: add list-objects filtering
rev-list: add list-objects filtering support
list-objects: filter objects in traverse_commit_list
oidset: add iterator methods to oidset
oidmap: add oidmap iterator methods
dir: allow exclusions from blob in addition to file
Git shows a message to tell the user that it is waiting for the
user to finish editing when spawning an editor, in case the editor
opens to a hidden window or somewhere obscure and the user gets
lost.
* ls/editor-waiting-message:
launch_editor(): indicate that Git waits for user input
refactor "dumb" terminal determination
Ancient part of codebase still shows dots after an abbreviated
object name just to show that it is not a full object name, but
these ellipses are confusing to people who newly discovered Git
who are used to seeing abbreviated object names and find them
confusing with the range syntax.
* ar/unconfuse-three-dots:
t2020: test variations that matter
t4013: test new output from diff --abbrev --raw
diff: diff_aligned_abbrev: remove ellipsis after abbreviated SHA-1 value
t4013: prepare for upcoming "diff --raw --abbrev" output format change
checkout: describe_detached_head: remove ellipsis after committish
print_sha1_ellipsis: introduce helper
Documentation: user-manual: limit usage of ellipsis
Documentation: revisions: fix typo: "three dot" ---> "three-dot" (in line with "two-dot").
The way "git worktree add" determines what branch to create from
where and checkout in the new worktree has been updated a bit.
* tg/worktree-create-tracking:
add worktree.guessRemote config option
worktree: add --guess-remote flag to add subcommand
worktree: make add <path> <branch> dwim
worktree: add --[no-]track option to the add subcommand
worktree: add can be created from any commit-ish
checkout: factor out functions to new lib file
The code internal to the recursive merge strategy was not fully
prepared to see a path that is renamed to try overwriting another
path that is only different in case on case insensitive systems.
This does not matter in the current code, but will start to matter
once the rename detection logic starts taking hints from nearby
paths moving to some directory and moves a new path along with them.
Historically, the diff machinery for rename detection had a
hardcoded limit of 32k paths; this is being lifted to allow users
trade cycles with a (possibly) easier to read result.
* en/rename-progress:
diffcore-rename: make diff-tree -l0 mean -l<large>
sequencer: show rename progress during cherry picks
diff: remove silent clamp of renameLimit
progress: fix progress meters when dealing with lots of work
sequencer: warn when internal merge may be suboptimal due to renameLimit
"git send-email" tries to see if the sendmail program is available
in /usr/lib and /usr/sbin; extend the list of locations to be
checked to also include directories on $PATH.
* fk/sendmail-from-path:
git-send-email: honor $PATH for sendmail binary
The tagnames "git log --decorate" uses to annotate the commits can
now be limited to subset of available refs with the two additional
options, --decorate-refs[-exclude]=<pattern>.
* ra/decorate-limit-refs:
log: add option to choose which refs to decorate
An infrastructure to define what hash function is used in Git is
introduced, and an effort to plumb that throughout various
codepaths has been started.
* bc/hash-algo:
repository: fix a sparse 'using integer as NULL pointer' warning
Switch empty tree and blob lookups to use hash abstraction
Integrate hash algorithm support with repo setup
Add structure representing hash algorithm
setup: expose enumerated repo info
launch_editor(): indicate that Git waits for user input
When a graphical GIT_EDITOR is spawned by a Git command that opens
and waits for user input (e.g. "git rebase -i"), then the editor window
might be obscured by other windows. The user might be left staring at
the original Git terminal window without even realizing that s/he needs
to interact with another window before Git can proceed. To this user Git
appears hanging.
Print a message that Git is waiting for editor input in the original
terminal and get rid of it when the editor returns, if the terminal
supports erasing the last line. Also, make sure that our message is
terminated with a whitespace so that any message the editor may show
upon starting up will be kept separate from our message.
Power users might not want to see this message or their editor might
already print such a message (e.g. emacsclient). Allow these users to
suppress the message by disabling the "advice.waitingForEditor" config.
The standard advise() function is not used here as it would always add
a newline which would make deleting the message harder.
Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
setup.c: fix comment about order of .git directory discovery
Since gitfiles were introduced in b44ebb19e (Add platform-independent
.git "symlink", 2008-02-20) the order of checks during .git directory
discovery is: gitfile, gitdir, bare repo. However, that commit did
only partially update the in-code comment describing this order,
missing the last line which still puts gitdir before gitfile.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff-tree: read the index so attribute checks work in bare repositories
A regression was introduced in 557a5998d (submodule: remove
gitmodules_config, 2017-08-03) to how attribute processing was handled
in bare repositories when running the diff-tree command.
By default the attribute system will first try to read ".gitattribute"
files from the working tree and then falls back to reading them from the
index if there isn't a copy checked out in the worktree. Prior to 557a5998d the index was read as a side effect of the call to
'gitmodules_config()' which ensured that the index was already populated
before entering the attribute subsystem.
Since the call to 'gitmodules_config()' was removed the index is no
longer being read so when the attribute system tries to read from the
in-memory index it doesn't find any ".gitattribute" entries effectively
ignoring any configured attributes.
Fix this by explicitly reading the index during the setup of diff-tree.
Reported-by: Ben Boeckel <ben.boeckel@kitware.com> Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some users might want to have the --guess-remote option introduced in
the previous commit on by default, so they don't have to type it out
every time they create a new worktree.
Add a config option worktree.guessRemote that allows users to configure
the default behaviour for themselves.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
worktree: add --guess-remote flag to add subcommand
Currently 'git worktree add <path>' creates a new branch named after the
basename of the <path>, that matches the HEAD of whichever worktree we
were on when calling "git worktree add <path>".
It's sometimes useful to have 'git worktree add <path> behave more like
the dwim machinery in 'git checkout <new-branch>', i.e. check if the new
branch name, derived from the basename of the <path>, uniquely matches
the branch name of a remote-tracking branch, and if so check out that
branch and set the upstream to the remote-tracking branch.
Add a new --guess-remote option that enables exactly that behaviour.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
trace: improve performance while category is disabled
Move just enough code from trace.c into trace.h header so all code
necessary to determine that trace is disabled could be inlined to
calling functions. Then perform the check if the trace key is
enabled sooner in call chain.
Signed-off-by: Gennady Kupava <gkupava@bloomberg.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The ssh-variant 'simple' introduced earlier broke existing
installations by not passing --port/-4/-6 and not diagnosing an
attempt to pass these as an error. Instead, default to
automatically detect how compatible the GIT_SSH/GIT_SSH_COMMAND is
to OpenSSH convention and then error out an invocation to make it
easier to diagnose connection errors.
* jn/ssh-wrappers:
connect: correct style of C-style comment
ssh: 'simple' variant does not support --port
ssh: 'simple' variant does not support -4/-6
ssh: 'auto' variant to select between 'ssh' and 'simple'
connect: split ssh option computation to its own function
connect: split ssh command line options into separate function
connect: split git:// setup into a separate function
connect: move no_fork fallback to git_tcp_connect
ssh test: make copy_ssh_wrapper_as clean up after itself
A new mechanism to upgrade the wire protocol in place is proposed
and demonstrated that it works with the older versions of Git
without harming them.
* bw/protocol-v1:
Documentation: document Extra Parameters
ssh: introduce a 'simple' ssh variant
i5700: add interop test for protocol transition
http: tell server that the client understands v1
connect: tell server that the client understands v1
connect: teach client to recognize v1 server response
upload-pack, receive-pack: introduce protocol version 1
daemon: recognize hidden request arguments
protocol: introduce protocol extension mechanisms
pkt-line: add packet_write function
connect: in ref advertisement, shallows are last
Internaly we use 0{40} as a placeholder object name to signal the
codepath that there is no such object (e.g. the fast-forward check
while "git fetch" stores a new remote-tracking ref says "we know
there is no 'old' thing pointed at by the ref, as we are creating
it anew" by passing 0{40} for the 'old' side), and expect that a
codepath to locate an in-core object to return NULL as a sign that
the object does not exist. A look-up for an object that does not
exist however is quite costly with a repository with large number
of packfiles. This access pattern has been optimized.
* jk/fewer-pack-rescan:
sha1_file: fast-path null sha1 as a missing object
everything_local: use "quick" object existence check
p5551: add a script to test fetch pack-dir rescans
t/perf/lib-pack: use fast-import checkpoint to create packs
p5550: factor out nonsense-pack creation
"git config --expiry-date gc.reflogexpire" can read "2.weeks" from
the configuration and report it as a timestamp, just like "--int"
would read "1k" and report 1024, to help consumption by scripts.
"git branch --set-upstream" has been deprecated and (sort of)
removed, as "--set-upstream-to" is the preferred one these days.
The documentation still had "--set-upstream" listed on its
synopsys section, which has been corrected.
* tz/branch-doc-remove-set-upstream:
branch doc: remove --set-upstream from synopsis
* cc/perf-run-config:
perf: store subsection results in "test-results/$GIT_PERF_SUBSECTION/"
perf/run: show name of rev being built
perf/run: add run_subsection()
perf/run: update get_var_from_env_or_config() for subsections
perf/run: add get_subsections()
perf/run: add calls to get_var_from_env_or_config()
perf/run: add GIT_PERF_DIRS_OR_REVS
perf/run: add get_var_from_env_or_config()
perf/run: add '--config' option to the 'run' script
"git checkout --recursive" may overwrite and rewind the history of
the branch that happens to be checked out in submodule
repositories, which might not be desirable. Detach the HEAD but
still allow the recursive checkout to succeed in such a case.
* sb/submodule-recursive-checkout-detach-head:
Documentation/checkout: clarify submodule HEADs to be detached
recursive submodules: detach HEAD from new state
Merge branch 'sb/test-cherry-pick-submodule-getting-in-a-way' into maint
The three-way merge performed by "git cherry-pick" was confused
when a new submodule was added in the meantime, which has been
fixed (or "papered over").
* sb/test-cherry-pick-submodule-getting-in-a-way:
merge-recursive: handle addition of submodule on our side of history
t/3512: demonstrate unrelated submodule/file conflict as cherry-pick failure
Merge branch 'pw/sequencer-recover-from-unlockable-index' into maint
The sequencer machinery (used by "git cherry-pick A..B", and "git
rebase -i", among other things) would have lost a commit if stopped
due to an unlockable index file, which has been fixed.
* pw/sequencer-recover-from-unlockable-index:
sequencer: reschedule pick if index can't be locked
When "git rebase" prepared an mailbox of changes and fed it to "git
am" to replay them, it was confused when a stray "From " happened
to be in the log message of one of the replayed changes. This has
been corrected.
* ew/rebase-mboxrd:
rebase: use mboxrd format to avoid split errors
Merge branch 'mh/avoid-rewriting-packed-refs' into maint
Recent update to the refs infrastructure implementation started
rewriting packed-refs file more often than before; this has been
optimized again for most trivial cases.
* mh/avoid-rewriting-packed-refs:
files-backend: don't rewrite the `packed-refs` file unnecessarily
t1409: check that `packed-refs` is not rewritten unnecessarily
Because our test suite is not about validating the working of the
shell, it is pointless to test variations of how a literal string
'yes' is quoted when assigned to an environment variable.
Instead, test various ways to spell 'yes' (we use strcasecmp() so
uppercased and capitalized variant should work just like 'yes'
spelled in all lowercase) and make sure we take them as 'yes'. That
is more relevant in testing Git.
Use newly-introduced finely-grained control to teach the diff-family to
honor the new environment GIT_PRINT_SHA1_ELLIPSIS and remove the
ellipses when it is not set.
Mentored-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Ann T Ropea <bedhanger@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
t4013: prepare for upcoming "diff --raw --abbrev" output format change
Most of the t4013 tests go through a list of sample command lines,
and each of them is executed and its output compared with an
expected one stored in t4013/ directory. Allow these lines to begin
with a colon followed by magic word(s) so that test conditions can
easily be tweaked.
The expected use that will happen in later steps of this is to run
tests expecting the traditional output and run the same test without
the GIT_PRINT_SHA1_ELLIPSIS=yes environment exported for (perhaps
some of) them, which will have to expect different output. Since
all of the existing tests are meant to run with the environment,
use the magic word "noellipses" to cause the variable not to be set
and exported.
As this step does not add any new test with the magic word, all
tests still run with the environment variable, expecting the
traditional output, but it will change soon.
Based-on-patch-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Ann T Ropea <bedhanger@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The hashmap API is just complicated enough that even at least one
long-time Git contributor has to look up how to use it every time he
finds a new use case. When that happens, it is really useful if the
provided example code is correct...
While at it, "fix a memory leak", avoid statements before variable
declarations, fix a const -> no-const cast, several %l specifiers (which
want to be %ld), avoid using an undefined constant, call scanf()
correctly, use FLEX_ALLOC_STR() where appropriate, and adjust the style
here and there.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/git-clone: improve description for submodule recursing
There have been a few complaints on the mailing list that git-clone doesn't
respect the `submodule.recurse` setting, which every other command (that
potentially knows how to deal with submodules) respects. In case of clone
this is not beneficial to respect as the user may not want to obtain all
submodules (assuming a pathspec of '.').
Improve the documentation such that the pathspec is mentioned in the
synopsis to alleviate the confusion around the submodule recursion flag
in git-clone.
While at it clarify that the option can be given multiple times for complex
pathspecs.
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach rev-list to support --no-filter to override a
previous --filter=<filter_spec> argument. This is
to be consistent with commands that use OPT_PARSE
macros.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach opt_parse_list_objects_filter() to take --no-filter
option and to free the contents of struct filter_options.
This command line argument will be automatically inherited
by commands using OPT_PARSE_LIST_OBJECTS_FILTER(); this
includes pack-objects.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
list-objects-filter-options: fix 'keword' typo in comment
Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: only match across submodule boundaries when requested
Commit 74ed43711fd (grep: enable recurse-submodules to work on <tree>
objects, 2016-12-16) taught 'tree_entry_interesting()' to be able to
match across submodule boundaries in the presence of wildcards. This is
done by performing literal matching up to the first wildcard and then
punting to the submodule itself to perform more accurate pattern
matching. Instead of introducing a new flag to request this behavior,
commit 74ed43711fd overloaded the already existing 'recursive' flag in
'struct pathspec' to request this behavior.
This leads to a bug where whenever any other caller has the 'recursive'
flag set as well as a pathspec with wildcards that all submodules will
be indicated as matches. One simple example of this is:
Fix this by introducing the new flag 'recurse_submodules' in 'struct
pathspec' and using this flag to determine if matches should be allowed
to cross submodule boundaries.
This fixes https://github.com/git-for-windows/git/issues/1371.
Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert author's name and e-mail address from the UTF-8 (or any other)
encoding in load_last_commit function the same way commit message is
converted.
Amending commits in git-gui without such conversion breaks UTF-8
strings. For example, "\305\201ukasz" (as written by git cat-file) becomes
"\303\205\302\201ukasz" in an amended commit.
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 63af4a8446 ("strbuf: make stripspace() part of strbuf",
2015-10-16), stripspace() was moved to strbuf and renamed to
strbuf_stripspace(). A "temporary" alias was added for the old name until
all topic branches had time to switch over. They have had time, so remove
the old alias.
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 180a9f2268 (provide a facility for "delayed" progress
reporting, 2007-04-20), the progress code has allowed
callers to skip showing progress if they have reached a
percentage-threshold of the total work before the delay
period passes.
But since 8aade107dd (progress: simplify "delayed" progress
API, 2017-08-19), that parameter is not available to outside
callers (we always passed zero after that commit, though
that was corrected in the previous commit to "100%").
Let's drop the threshold code, which never triggers in
any meaningful way.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
progress: set default delay threshold to 100%, not 0%
Commit 8aade107dd (progress: simplify "delayed" progress
API, 2017-08-19) dropped the parameter by which callers
could say "show my progress only if I haven't passed M%
progress after N seconds". The intent was to just show
nothing for 2 seconds, and then always progress after that.
But we flipped the logic in the wrapper: it sets M=0,
meaning that we'd almost _never_ show progress after 2
seconds, since we'd generally have made some progress. This
should have been 100%, not 0%.
We were fooled by existing calls like:
start_progress_delay("foo", 0, 0, 2);
which behaved this way. The trick is that the first "0"
there is "how many items total", and there zero means "we
don't know". And without knowing that, we cannot compute a
completed percent at all, and we ignored the threshold
parameter entirely! Modeling our wrapper after that broke
callers which pass a non-zero value for "total".
We can switch to the intended behavior by using "100" in the
wrapper call.
Reported-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_file: use strbuf_add() instead of strbuf_addf()
Replace use of strbuf_addf() with strbuf_add() when enumerating
loose objects in for_each_file_in_obj_subdir(). Since we already
check the length and hex-values of the string before consuming
the path, we can prevent extra computation by using the lower-
level method.
One consumer of for_each_file_in_obj_subdir() is the abbreviation
code. OID abbreviations use a cached list of loose objects (per
object subdirectory) to make repeated queries fast, but there is
significant cache load time when there are many loose objects.
Most repositories do not have many loose objects before repacking,
but in the GVFS case the repos can grow to have millions of loose
objects. Profiling 'git log' performance in GitForWindows on a
GVFS-enabled repo with ~2.5 million loose objects revealed 12% of
the CPU time was spent in strbuf_addf().
Add a new performance test to p4211-line-log.sh that is more
sensitive to this cache-loading. By limiting to 1000 commits, we
more closely resemble user wait time when reading history into a
pager.
For a copy of the Linux repo with two ~512 MB packfiles and ~572K
loose objects, running 'git log --oneline --parents --raw -1000'
had the following performance:
HEAD~1 HEAD
----------------------------------------
7.70(7.15+0.54) 7.44(7.09+0.29) -3.4%
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a helper print_sha1_ellipsis() that pays attention to the
GIT_PRINT_SHA1_ELLIPSIS environment variable, and prepare the tests to
unconditionally set it for the test pieces that will be broken once the code
stops showing the extra dots by default.
The removal of these dots is merely a plan at this step and has not happened
yet but soon will.
Document GIT_PRINT_SHA1_ELLIPSIS.
Signed-off-by: Ann T Ropea <bedhanger@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: user-manual: limit usage of ellipsis
There is no need to use full 40-hex to identify the object names like
the examples hint at by omitting the tail part of an object name as if
that has to be spelled out but the example omits them only for brevity.
Give examples using abbreviated object names without ellipses just like
how people do in real life.
Signed-off-by: Ann T Ropea <bedhanger@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diffcore-rename: make diff-tree -l0 mean -l<large>
In the documentation of diff-tree, it is stated that the -l option
"prevents rename/copy detection from running if the number of
rename/copy targets exceeds the specified number". The documentation
does not mention any special handling for the number 0, but the
implementation before commit 9f7e4bfa3b ("diff: remove silent clamp of
renameLimit", 2017-11-13) treated 0 as a special value indicating that
the rename limit is to be a very large number instead.
The commit 9f7e4bfa3b changed that behavior, treating 0 as 0. Revert
this behavior to what it was previously. This allows existing scripts
and tools that use "-l0" to continue working. The alternative (to have
"-l0" suppress rename detection) is probably much less useful, since
users can just refrain from specifying -M and/or -C to have the same
effect.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git grep -W", "git diff -W" and their friends learned a heuristic
to extend a pre-context beyond the line that matches the "function
pattern" (aka "diff.*.xfuncname") to include a comment block, if
exists, that immediately precedes it.
* rs/include-comments-before-the-function-header:
grep: show non-empty lines before functions with -W
grep: update boundary variable for pre-context
t7810: improve check of -W with user-defined function lines
xdiff: show non-empty lines before functions with -W
xdiff: factor out is_func_rec()
t4051: add test for comments preceding function lines
"git branch --list" learned to show its output through the pager by
default when the output is going to a terminal, which is controlled
by the pager.branch configuration variable. This is similar to a
recent change to "git tag --list".
* ma/branch-list-paginate:
branch: change default of `pager.branch` to "on"
branch: respect `pager.branch` in list-mode only
t7006: add tests for how git branch paginates
"git branch" and "git checkout -b" are now forbidden from creating
a branch whose name is "HEAD".
* jc/branch-name-sanity:
builtin/branch: remove redundant check for HEAD
branch: correctly reject refs/heads/{-dash,HEAD}
branch: split validate_new_branchname() into two
branch: streamline "attr_only" handling in validate_new_branchname()
repository: fix a sparse 'using integer as NULL pointer' warning
Commit 78a6766802 ("Integrate hash algorithm support with repo setup",
2017-11-12) added a 'const struct git_hash_algo *hash_algo' field to the
repository structure, without modifying the initializer of the 'the_repo'
variable. This does not actually introduce a bug, since the '0' initializer
for the 'ignore_env:1' bit-field is interpreted as a NULL pointer (hence
the warning), and the final field (now with no initializer) receives a
default '0'.
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Doc/checkout: checking out using @{-N} can lead to detached state
@{-N} is a syntax for the N-th last "checkout" and not the N-th
last "branch". Therefore, in some cases using `git checkout @{-$N}`
DOES lead to a "detached HEAD" state. This can also be ensured by
the commit message of 75d6e552a (Documentation: @{-N} can refer to
a commit, 2014-01-19) which clearly specifies how @{-N} can be used
to refer not only to a branch but also to a commit.
Correct the misleading sentence which states that @{-N} doesn't
detach HEAD.
Signed-off-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>