clone: forbid --bare --separate-git-dir <dir>

The --separate-git-dir option was introduced to make it simple to put
the git directory somewhere outside the worktree, for example when
cloning a repository for use as a submodule.

It was not intended for use when creating a bare repository. In that
case there is no worktree and it is more natural to directly clone the
repository and create a .git file as separate steps:

        git clone --bare /path/to/repo.git bar.git
        printf 'gitdir: bar.git\n' >foo.git

Forbid the combination, making the command easier to explain.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-clean: Display more accurate delete messages

(1) Only print out the names of the files and directories that got
    actually deleted. Also do not mention that we are not removing
    directories when the user did not ask us to do so with '-d'.
(2) Show ignore message for skipped untracked git repositories.

Consider the following repo layout:

  test.git/
    |-- tracked_dir/
    |     |-- some_tracked_file
    |     |-- some_untracked_file
    |-- tracked_file
    |-- untracked_file
    |-- untracked_foo/
    |     |-- bar/
    |     |     |-- bar.txt
    |     |-- emptydir/
    |     |-- frotz.git/
    |           |-- frotz.tx
    |-- untracked_some.git/
          |-- some.txt

Suppose the user issues 'git clean -fd' from the test.git directory.

When -d option is used and untracked directory 'foo' contains a
subdirectory 'frotz.git' that is managed by a different git repository
therefore it will not be removed.

  $ git clean -fd
  Removing tracked_dir/some_untracked_file
  Removing untracked_file
  Removing untracked_foo/
  Removing untracked_some.git/

The message displayed to the user is slightly misleading. The foo/
directory has not been removed because of foo/frotz.git still exists.
On the other hand the subdirectories 'bar' and 'emptydir' have been
deleted but they're not mentioned anywhere. Also, untracked_some.git
has not been removed either.

This behaviour is the result of the way the deletion of untracked
directories are reported. In the current implementation they are
deleted recursively but only the name of the top most directory is
printed out. The calling function does not know about any
subdirectories that could not be removed during the recursion.

Improve the way the deleted directories are reported back to
the user:
  (1) Create a recursive delete function 'remove_dirs' in builtin/clean.c
      to run in both dry_run and delete modes with the delete logic as
      follows:
        (a) Check if the current directory to be deleted is an untracked
            git repository. If it is and --force --force option is not set
            do not touch this directory, print ignore message, set dir_gone
            flag to false for the caller and return.
        (b) Otherwise for each item in current directory:
              (i)   If current directory cannot be accessed, print warning,
                    set dir_gone flag to false and return.
              (ii)  If the item is a subdirectory recurse into it,
                    check for the returned value of the dir_gone flag.
                    If the subdirectory is gone, add the name of the deleted
                    directory to a list of successfully removed items 'dels'.
                    Else set the dir_gone flag as the current directory
                    cannot be removed because we have at least one subdirectory
                    hanging around.
              (iii) If it is a file try to remove it. If success add the
                    file name to the 'dels' list, else print error and set
                    dir_gone flag to false.
        (c) After we finished deleting all items in the current directory and
            the dir_gone flag is still true, remove the directory itself.
            If failed set the dir_gone flag to false.

        (d) If the current directory cannot be deleted because the dir_gone flag
            has been set to false, print out all the successfully deleted items
            for this directory from the 'dels' list.
        (e) We're done with the current directory, return.

  (2) Modify the cmd_clean() function to:
        (a) call the recursive delete function 'remove_dirs()' for each
            topmost directory it wants to remove
        (b) check for the returned value of dir_gone flag. If it's true
            print the name of the directory as being removed.

Consider the output of the improved version:

  $ git clean -fd
  Removing tracked_dir/some_untracked_file
  Removing untracked_file
  Skipping repository untracked_foo/frotz.git
  Removing untracked_foo/bar
  Removing untracked_foo/emptydir
  Skipping repository untracked_some.git/

Now it displays only the file and directory names that got actually
deleted and shows the name of the untracked git repositories it ignored.

Reported-by: Soren Brinkmann <soren.brinkmann@xilinx.com>

Signed-off-by: Zoltan Klinger <zoltan.klinger@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rebase --preserve-merges: keep all merge commits including empty ones

Since 90e1818f9a  (git-rebase: add keep_empty flag, 2012-04-20)
'git rebase --preserve-merges' fails to preserve empty merge commits
unless --keep-empty is also specified.  Merge commits should be
preserved in order to preserve the structure of the rebased graph,
even if the merge commit does not introduce changes to the parent.

Teach rebase not to drop merge commits only because they are empty.

A special case which is not handled by this change is for a merge commit
whose parents are now the same commit because all the previous different
parents have been dropped as a result of this rebase or some previous
operation.

Signed-off-by: Phil Hord <hordp@cisco.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
attr: fix off-by-one directory component length calculation

94bc671 (Add directory pattern matching to attributes - 2012-12-08)
uses find_basename() to calculate the length of directory part in
prepare_attr_stack. This function expects the directory without the
trailing slash (as "origin" field in match_attr struct is without the
trailing slash). find_basename() includes the trailing slash and
confuses push/pop algorithm.

Consider path = "abc/def" and the push down code:

	while (1) {
		len = strlen(attr_stack->origin);
		if (dirlen <= len)
			break;
		cp = memchr(path + len + 1, '/', dirlen - len - 1);
		if (!cp)
			cp = path + dirlen;

dirlen is 4, not 3, without this patch. So when attr_stack->origin is
"abc", it'll miss the exit condition because 4 <= 3 is wrong. It'll
then try to push "abc/" down the attr stack (because "cp" would be
NULL). So we have both "abc" and "abc/" in the stack.

Next time when "abc/ghi" is checked, "abc/" is popped out because of
the off-by-one dirlen, only to be pushed back in again by the above
code. This repeats for all files in the same directory. Which means
at least one failed open syscall per file, or more if .gitattributes
exists.

This is the perf result with 10 runs on git.git:

Test                                     94bc671^          94bc671                   HEAD
----------------------------------------------------------------------------------------------------------
7810.1: grep worktree, cheap regex       0.02(0.01+0.04)   0.05(0.03+0.05) +150.0%   0.02(0.01+0.04) +0.0%
7810.2: grep worktree, expensive regex   0.25(0.94+0.01)   0.26(0.94+0.02) +4.0%     0.25(0.93+0.02) +0.0%
7810.3: grep --cached, cheap regex       0.11(0.10+0.00)   0.12(0.10+0.02) +9.1%     0.10(0.10+0.00) -9.1%
7810.4: grep --cached, expensive regex   0.61(0.60+0.01)   0.62(0.61+0.01) +1.6%     0.61(0.60+0.00) +0.0%

Reported-by: Ross Lagerwall <rosslagerwall@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset $pathspec: no need to discard index

Since 34110cd (Make 'unpack_trees()' have a separate source and
destination index, 2008-03-06), the index no longer gets clobbered by
do_diff_cache() and we can remove the code for discarding and
re-reading it.

There are two paths to update_index_refresh() from cmd_reset(), but on
both paths, either read_cache() or read_cache_unmerged() will have
been called, so the call to read_cache() in this method is redundant
(although practically free).

This speeds up "git reset -- ." a little on the linux-2.6 repo (best
of five, warm cache):

        Before      After
real    0m0.093s    0m0.080s
user    0m0.040s    0m0.020s
sys     0m0.050s    0m0.050s

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset $pathspec: exit with code 0 if successful

"git reset $pathspec" currently exits with a non-zero exit code if the
worktree is dirty after resetting, which is inconsistent with reset
without pathspec, and it makes it harder to know whether the command
really failed. Change it to exit with code 0 regardless of whether the
worktree is dirty so that non-zero indicates an error.

This makes the 4 "disambiguation" test cases in t7102 clearer since
they all used to "fail", 3 of which "failed" due to changes in the
work tree. Now only the ambiguous one fails.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: pass pathspec around instead of (prefix, argv) pair

We use the path arguments in two places in reset.c: in
interactive_reset() and read_from_tree(). Both of these call
get_pathspec(), so we pass the (prefix, argv) pair to both
functions. Move the call to get_pathspec() out of these methods, for
two reasons: 1) One argument is simpler than two. 2) It lets us use
the (arguably clearer) "if (pathspec)" in place of "if (i < argc)".

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset: don't allow "git reset -- $pathspec" in bare repo

Running e.g. "git reset ." in a bare repo results in an index file
being created from the HEAD commit. The differences compared to the
index are then printed as usual, but since there is no worktree, it
will appear as if all files are deleted. For example, in a bare clone
of git.git:

  Unstaged changes after reset:
  D       .gitattributes
  D       .gitignore
  D       .mailmap
  ...

This happens because the check for is_bare_repository() happens after
we branch off into read_from_tree() to reset with paths. Fix by moving
the branching point after the check.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: extract function for parsing arguments

Declutter cmd_reset() a bit by moving out the argument parsing to its
own function.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: remove unnecessary variable 'i'

Throughout most of parse_args(), the variable 'i' remains at 0. Many
references are still made to the variable even when it could only have
the value 0. This made at least me, who has relatively little
experience with C programming styles, think that parts of the function
was meant to be part of a loop. To avoid such confusion, remove the
variable and also the 'argc' parameter and check for NULL trailing
argv instead.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: extract function for updating {ORIG_,}HEAD

By extracting the code for updating the HEAD and ORIG_HEAD symbolic
references to a separate function, we declutter cmd_reset() a bit and
we make it clear that e.g. the four variables {,sha1_}{,old_}orig are
only used by this code.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: share call to die_if_unmerged_cache()

Use a single condition to guard the call to die_if_unmerged_cache for
both --soft and --keep. This avoids the small distraction of the
precondition check from the logic following it.

Also change an instance of

  if (e)
    err = err || f();

to the almost as short, but clearer

  if (e && !err)
    err = f();

(which is equivalent since we only care whether exit code is 0)

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset --keep: only write index file once

"git reset --keep" calls reset_index_file() twice, first doing a
two-way merge to the target revision, updating the index and worktree,
and then resetting the index. After each call, we write the index
file.

In the unlikely event that the second call to reset_index_file()
fails, the index will have been merged to the target revision, but
HEAD will not be updated, leaving the user with a dirty index.

By moving the locking, writing and committing out of
reset_index_file() and into the caller, we can avoid writing the index
twice, thereby making the sure we don't end up in the half-way reset
state. As a bonus, we speed up "git reset --keep" a little on the
linux-2.6 repo (best of five, warm cache):

        Before      After
real    0m0.315s    0m0.296s
user    0m0.290s    0m0.280s
sys     0m0.020s    0m0.010s

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset: avoid redundant error message

If writing or committing the new index file fails, we print "Could not
write new index file." followed by "Could not reset index file to
revision $rev.". The first message seems to imply the second, so print
only the first message.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: replace switch by if-else

The switch statement towards the end of reset.c is missing case arms
for KEEP and MERGE for no obvious reason, and soon the only non-empty
case arm will be the one for HARD. So let's proactively replace it by
if-else, which will let us move one if statement out without leaving
funny-looking left-overs.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: move update_index_refresh() call out of read_from_tree()

The final part of cmd_reset() essentially looks like:

  if (pathspec) {
    ...
    read_from_tree(...);
  } else {
    ...
    reset_index(...);
    update_index_refresh(...);
    ...
  }

where read_from_tree() internally also calls
update_index_refresh(). Move the call to update_index_refresh() out of
read_from_tree for symmetry with the 'else' block, making
read_from_tree() and reset_index() closer in functionality.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: move lock, write and commit out of update_index_refresh()

In preparation for the/a following patch, move the locking, writing
and committing of the index file out of update_index_refresh(). The
code duplication caused will soon be taken care of. What remains of
update_index_refresh() is just one line, but it is still called from
two places, so let's leave it for now.

In the process, we expose and fix the minor UI bug that makes us print
"Could not refresh index" when we fail to write the index file when
invoked with a pathspec. Copy the error message from the pathspec-less
codepath ("Could not write new index file.").

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset [--mixed]: only write index file once

When doing a mixed reset without paths, the index is locked, read,
reset, and written back as part of the actual reset operation (in
reset_index()). Then, when showing the list of worktree modifications,
we lock the index again, refresh it, and write it.

Change this so we only write the index once, making "git reset" a
little faster. It does mean that the index lock will be held a little
longer, but the difference is small compared to the time spent
refreshing the index.

There is one minor functional difference: We used to say "Could not
write new index file." if the first write failed, and "Could not
refresh index" if the second write failed. Now, we will only use the
first message.

This speeds up "git reset" a little on the linux-2.6 repo (best of
five, warm cache):

        Before      After
real    0m0.239s    0m0.214s
user    0m0.160s    0m0.130s
sys     0m0.070s    0m0.080s

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: finish entire cmd_reset() whether or not pathspec is given

By not returning from inside the "if (pathspec)" block, we can let the
pathspec-aware and pathspec-less code share a bit more, making it
easier to make future changes that should affect both cases. This also
highlights the similarity between read_from_tree() and reset_index().

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset.c: inline update_index_refresh()

Now that there is only one caller left to the single-line method
update_index_refresh(), inline it.

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>