The logic in 83ae209b (checkout branch: prime cache-tree fully,
2009-04-20) is bogus; checkout can switch branches with a dirty
index and in such a case the tree won't match HEAD.

Add t2014-switch to catch this breakage.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMike Ralphson <mike@abacus.co.uk>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When switching to another branch, the earlier code relied on incremental
invalidation of cache-tree entries to degrade it.  While it is not wrong
per-se, we know that the resulting index must fully match the branch we
are switching to unless the -m (merge) option is used.

We should simply fully re-prime the cache-tree using the new tree object
in such a case.  And for safety, invalidate the cache-tree as a whole in
other cases.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The interface to build cache-tree belongs there.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Most of the time when we give branch name in the message, we quote it
inside a pair of single-quotes.  git-checkout uses double-quotes; this
patch corrects the inconsistency.
Signed-off-by: NJari Aalto <jari.aalto@cante.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

While 'git checkout <submodule>' should not update the submodule's
working directory, it should update the index.  This is in line with
how submodules are handled in the rest of Git.

While at it, test 'git reset [<commit>] <submodule>', too.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMiklos Vajna <vmiklos@frugalware.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This allows a common calling sequence

	strbuf_branchname(&ref, name);
	strbuf_splice(&ref, 0, 0, "refs/heads/", 11);
	if (check_ref_format(ref.buf))
		die(...);

to be refactored into

	if (strbuf_check_branch_ref(&ref, name))
		die(...);
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The function takes a user-supplied string that is supposed to be a branch
name, and puts it in a strbuf after expanding possible shorthand notation.

A handful of open coded sequence to do this in the existing code have been
changed to use this helper function.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These allow you to say "git checkout @{-2}" to switch to the branch two
"branch switching" ago by pretending as if you typed the name of that
branch.  As it is likely that we will be introducing more short-hands to
write the name of a branch without writing it explicitly, rename the
functions from "nth_last_branch" to more generic "branch_name", to prepare
for different semantics.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Code that calls diff_setup(), including via init_revisions(), should later call
diff_setup_done(), possibly via setup_revisions(). Failure to do so could cause
errors, especially in the future when we add responsibilities to
diff_setup_done(). This instance causes no known errors with the present code.
But it resulted in an error with an experimental patch.
Signed-off-by: NKeith Cascio <keith@cs.ucla.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

By having flags represented as bits in the new member variable 'flags',
it will be easier to use parse_options when dir_struct is involved.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Have '-' mean the same as '@{-1}', i.e., the last branch we were on.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Have the lookup only look at "interesting" checkouts, meaning those
that tell you "Already on ..." don't count even though they also cause
a reflog entry.

Let interpret_nth_last_branch() return the number of characters
parsed, so that git-checkout can verify that the branch spec was
@{-N}, not @{-1}^2 or something like that.  (The latter will be added
later.)
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Implement a shortcut @{-N} for the N-th last branch checked out, that
works by parsing the reflog for the message added by previous
git-checkout invocations.  We expand the @{-N} to the branch name, so
that you end up on an attached HEAD on that branch.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

A function that runs a hook is used in several Git commands.
builtin-commit.c has the one that is most general for cases without
piping. The one in builtin-gc.c prints some useful warnings.
This patch moves a merged version of these variants into libgit and
lets the other builtins use this libified run_hook().

The run_hook() function used in receive-pack.c feeds the standard
input of the pre-receive or post-receive hooks. This function is
renamed to run_receive_hook() because the libified run_hook() cannot
handle this.
Mentored-by: NDaniel Barkalow <barkalow@iabervon.org>
Mentored-by: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NStephan Beyer <s-beyer@gmx.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In the case of

	git init
	echo exit >.git/hooks/post-checkout
	chmod +x .git/hooks/post-checkout
	touch foo
	git add foo
	rm foo
	git checkout -- foo

git-checkout resulted in a Segmentation fault, because there is no new
branch set for the post-checkout hook.

This patch makes use of the null SHA as it is set for the old branch.

While at it, I removed the xstrdup() around the sha1_to_hex(...) calls
in builtin-checkout.c/post_checkout_hook() because sha1_to_hex()
uses four buffers for the hex-dumped SHA and we only need two.
(Duplicating one buffer is only needed if we need more than four.)
Signed-off-by: NStephan Beyer <s-beyer@gmx.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Both versions have the same functionality. This removes any
redundancy.

This also adds makes two extensions to match_pathspec:

- If pathspec is NULL, return 1. This reflects the behavior of git
  commands, for which no paths usually means "match all paths".

- If seen is NULL, do not use it.
Signed-off-by: NClemens Buchacher <drizzd@aon.at>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git checkout -b newbranch $commit^{tree}" mistakenly created a new branch
rooted at the current HEAD, because in that case, the two structure fields
used to see if the command was invoked without any argument (hence it
needs to default to checking out the HEAD) were populated incorrectly.

Upon seeing a command line argument that we took as a rev, we should store
that string in new.name, even if that does not name a commit.  This will
correctly trigger the existing safety logic.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Acked-by: NDaniel Barkalow <barkalow@iabervon.org>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

I think it's unnecessary to warn that the checkout has been forced due to an
unborn current branch if -f has been explicitly passed.  For one project, I am
using git-new-workdir to create workdirs from a bare repository whose HEAD is
set to an unborn branch, and this warning started to irritate me.
Signed-off-by: NMatt McCutchen <matt@mattmccutchen.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier commit 55218834 (checkout: do not lose staged removal, 2008-09-07)
tightened the rule to prevent switching branches from losing local
changes, so that staged removal of paths can be protected, while
attempting to keep a loophole to still allow a special case of switching
out of an un-checked-out state.

However, the loophole was made a bit too tight, and did not allow
switching from one branch (in an un-checked-out state) to check out
another branch.

The change to builtin-checkout.c in this commit loosens it to allow this,
by not insisting the original commit and the new commit to be the same.

It also introduces a new function, is_index_unborn (and an associated
macro, is_cache_unborn), to check if the repository is truly in an
un-checked-out state more reliably, by making sure that $GIT_INDEX_FILE
did not exist when populating the in-core index structure.  A few places
the earlier commit 55218834 added the check for the initial checkout
condition are updated to use this function.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When using alternates, it is possible for HEAD to end up pointing to
an invalid commit. git checkout should be able to recover from that
situation without crashing.
Signed-off-by: NAlexandre Julliard <julliard@winehq.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The code to complain when -b is not given but an explicit --track/--no-track
override was given from the command line was unchanged on one branch and
reworked on the other branch.  The merge result incorrectly kept it.

Spotted by Matt McCutchen.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Many call sites use strbuf_init(&foo, 0) to initialize local
strbuf variable "foo" which has not been accessed since its
declaration. These can be replaced with a static initialization
using the STRBUF_INIT macro which is just as readable, saves a
function call, and takes up fewer lines.
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Signed-off-by: NDmitry Potapov <dpotapov@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Signed-off-by: NJonas Fonseca <fonseca@diku.dk>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

If you fail to update refs to change branches in checkout, your index
and working tree are left already updated. We don't have an easy way
to undo this, but at least we can check things that would make the
creation of a new branch fail. These checks were in the shell version,
and were lost in the C conversion.

The messages are from the shell version, and should probably be made nicer.

[jc: added test to t7201]
Signed-off-by: NDaniel Barkalow <barkalow@iabervon.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The logic to checkout a different commit implements the safety to never
lose user's local changes.  For example, switching from a commit to
another commit, when you have changed a path that is different between
them, need to merge your changes to the version from the switched-to
commit, which you may not necessarily be able to resolve easily.  By
default, "git checkout" refused to switch branches, to give you a chance
to stash your local changes (or use "-m" to merge, accepting the risks of
getting conflicts).

This safety, however, had one deliberate hole since early June 2005.  When
your local change was to remove a path (and optionally to stage that
removal), the command checked out the path from the switched-to commit
nevertheless.

This was to allow an initial checkout to happen smoothly (e.g. an initial
checkout is done by starting with an empty index and switching from the
commit at the HEAD to the same commit).  We can tighten the rule slightly
to allow this special case to pass, without losing sight of removal
explicitly done by the user, by noticing if the index is truly empty when
the operation begins.

For historical background, see:

    http://thread.gmane.org/gmane.comp.version-control.git/4641/focus=4646

This case is marked as *0* in the message, which both Linus and I said "it
feels somewhat wrong but otherwise we cannot start from an empty index".
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The shell version of git checkout would print:

  Previous HEAD position was 1234abcd... commit subject line

when leaving a detached HEAD for another commit. Ths C
version attempted to implement this, but got the condition
wrong such that the behavior never triggered.

This patch simplifies the conditions for showing the message
to the ones used by the shell version: any time we are
leaving a detached HEAD and the new and old commits are not
the same (this suppresses it for the "git checkout -b new"
case recommended when you enter the detached state).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This new option does essentially the same thing as -m option when checking
unmerged paths out of the index, but it uses the specified style instead
of configured merge.conflictstyle.

Setting "merge.conflictstyle" to "diff3" is usually less useful than using
the default "merge" style, because the latter allows a conflict that
results by both sides changing the same region in a very similar way to
get simplified substancially by reducing the common lines.  However, when
one side removed a group of lines (perhaps a function was moved to some
other file) while the other side modified it, the default "merge" style
does not give any clue as to why the hunk is left conflicting.  You would
need the original to understand what is going on.

The recommended use would be not to set merge.conflictstyle variable so
that you would usually use the default "merge" style conflict, and when
the result in a path in a particular merge is too hard to understand, use
"git checkout --conflict=diff3 $path" to check it out with the original to
review what is going on.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This makes it possible to avoid passing the labels of branches as
arguments to merge_recursive(), merge_trees() and
merge_recursive_generic().

It also takes care of subtree merge, output buffering, verbosity, and
rename limits - these were global variables till now in
merge-recursive.c.

A new function, named init_merge_options(), is introduced as well, it
clears the struct merge_info, then initializes with default values,
finally updates the default values based on the config and environment
variables.
Signed-off-by: NMiklos Vajna <vmiklos@frugalware.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This teaches git-checkout to recreate a merge out of unmerged
index entries while resolving conflicts.

With this patch, checking out an unmerged path from the index
now have the following possibilities:

 * Without any option, an attempt to checkout an unmerged path
   will atomically fail (i.e. no other cleanly-merged paths are
   checked out either);

 * With "-f", other cleanly-merged paths are checked out, and
   unmerged paths are ignored;

 * With "--ours" or "--theirs, the contents from the specified
   stage is checked out;

 * With "-m" (we should add "--merge" as synonym), the 3-way merge
   is recreated from the staged object names and checked out.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This lets you to check out 'our' (or 'their') version of an
unmerged path out of the index while resolving conflicts.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier we made "git checkout $pathspec" to atomically refuse
the operation of $pathspec matched any path with unmerged
stages.  This patch allows:

    $ git checkout -f a b c

to ignore, instead of error out on, such unmerged paths.  The
fix to prevent checkout of an unmerged path from random stages
is still there.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

During a conflicted merge when you have unmerged stages for a
path F in the index, if you said:

    $ git checkout F

we rewrote F as many times as we have stages for it, and the
last one (typically "theirs") was left in the work tree, without
resolving the conflict.

This fixes it by noticing that a specified pathspec pattern
matches an unmerged path, and by erroring out.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The code handles additionally "refs/remotes/<something>/name",
"remotes/<something>/name", and "refs/<namespace>/name".
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

What does the user most likely want with this command?

	$ git checkout --track origin/next

Exactly.  A branch called 'next', that tracks origin's branch 'next'.
Make it so.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The patch is twofold: it moves the option consistency checks just under
the parse_options call so that it doesn't get in the way of the tree
reference vs. pathspecs desambiguation.

The other part rewrites the way to understand arguments so that when
git-checkout fails it does with an understandable message. Compared to the
previous behavior we now have:

  - a better error message when doing:

        git checkout <blob reference> --

    now complains about the reference not pointing to a tree, instead of
    things like:

        error: pathspec <blob reference> did not match any file(s) known to git.
        error: pathspec '--' did not match any file(s) known to git.

  - a better error message when doing:

        git checkout <path> --

    It now complains about <path> not being a reference instead of the
    completely obscure:

        error: pathspec '--' did not match any file(s) known to git.

  - an error when -- wasn't used, and the first argument is ambiguous
    (i.e. can be interpreted as both ref and as path).
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This fixes an issue when you use:

    $ git checkout -- <path1> [<paths>...]

and that <path1> can also be understood as a reference. git-checkout
mistakenly understands this as the same as:

    $ git checkout <path1> -- [<paths>...]

because parse-options was eating the '--' and the argument parser thought
he was parsing:

    $ git checkout <path1> [<paths>...]

Where there indeed is an ambiguity
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>