Teach 'git merge' the --abort option, which verifies the existence of
MERGE_HEAD and then invokes 'git reset --merge' to abort the current
in-progress merge and attempt to reconstruct the pre-merge state.

The reason for adding this option is to provide a user interface for
aborting an in-progress merge that is consistent with the interface
for aborting a rebase ('git rebase --abort'), aborting the application
of a patch series ('git am --abort'), and aborting an in-progress notes
merge ('git notes merge --abort').

The patch includes documentation and testcases that explain and verify
the various scenarios in which 'git merge --abort' can run. The
testcases also document the cases in which 'git merge --abort' is
unable to correctly restore the pre-merge state (look for the '###'
comments towards the bottom of t/t7609-merge-abort.sh).

This patch has been improved by the following contributions:
- Jonathan Nieder: Move test documentation into test_description

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Reorder the initial part of builtin/merge.c:cmd_merge() so that command-line
options are parsed _before_ we load the index and check for MERGE_HEAD
(and exits if it exists). This does not change the behaviour of 'git merge',
but is needed in preparation for the implementation of 'git merge --abort'
(which requires MERGE_HEAD to be present).

This patch has been improved by the following contributions:
- Junio C Hamano: fixup minor style issues

Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Script may use 'git notes get-ref' to easily retrieve the current notes ref.
Suggested-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Notes trees may exist at different fanout levels internally. This
implementation detail should not be visible to the user, and it should
certainly not affect the merging of notes tree.

This patch adds testcases verifying the correctness of 'git notes merge'
when merging notes trees at different fanout levels.

This patch has been improved by the following contributions:
- Junio C Hamano: Portability: Don't string-compare 'wc -l' output

Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This new strategy is similar to "concatenate", but in addition to
concatenating the two note candidates, this strategy sorts the resulting
lines, and removes duplicate lines from the result. This is equivalent to
applying the "cat | sort | uniq" shell pipeline to the two note candidates.

This strategy is useful if the notes follow a line-based format where one
wants to avoid duplicate lines in the merge result.

Note that if either of the note candidates contain duplicate lines _prior_
to the merge, these will also be removed by this merge strategy.

The patch also contains tests and documentation for the new strategy.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When manually resolving a notes merge, if the merging ref has moved since
the merge started, we should fail to complete the merge, and alert the user
to what's going on.

This situation may arise if you start a 'git notes merge' which results in
conflicts, and you then update the current notes ref (using for example
'git notes add/copy/amend/edit/remove/prune', 'git update-ref', etc.),
before you get around to resolving the notes conflicts and calling
'git notes merge --commit'.

We detect this situation by comparing the first parent of the partial merge
commit (which was created when the merge started) to the current value of the
merging notes ref (pointed to by the .git/NOTES_MERGE_REF symref).

If we don't fail in this situation, the notes merge commit would overwrite
the updated notes ref, thus losing the changes that happened in the meantime.

The patch includes a testcase verifying that we fail correctly in this
situation.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This brings notes merge in line with regular merge's behaviour.

This patch has been improved by the following contributions:
- Ævar Arnfjörð Bjarmason: Don't use C99 comments.

Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When the notes merge conflicts in .git/NOTES_MERGE_WORKTREE have been
resolved, we need to record a new notes commit on the appropriate notes
ref with the resolved notes.

This patch implements 'git notes merge --commit' which the user should
run after resolving conflicts in the notes merge worktree. This command
finalizes the notes merge by recombining the partial notes tree from
part 1 with the now-resolved conflicts in the notes merge worktree in a
merge commit, and updating the appropriate ref to this merge commit.

In order to correctly finalize the merge, we need to keep track of three
things:

- The partial merge result from part 1, containing the auto-merged notes.
  This is now stored into a ref called .git/NOTES_MERGE_PARTIAL.
- The unmerged notes. These are already stored in
  .git/NOTES_MERGE_WORKTREE, thanks to part 1.
- The notes ref to be updated by the finalized merge result. This is now
  stored in a symref called .git/NOTES_MERGE_REF.

In addition to "git notes merge --commit", which uses the above details
to create the finalized notes merge commit, this patch also implements
"git notes merge --reset", which aborts the ongoing notes merge by simply
removing the files/directory described above.

FTR, "git notes merge --commit" reuses "git notes merge --reset" to remove
the information described above (.git/NOTES_MERGE_*) after the notes merge
have been successfully finalized.

The patch also contains documentation and testcases for the two new options.

This patch has been improved by the following contributions:
- Ævar Arnfjörð Bjarmason: Fix nonsense sentence in --commit description
- Sverre Rabbelier: Rename --reset to --abort

Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Thanks-to: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Conflicts (that are to be resolved manually) are written into a special-
purpose working tree, located at .git/NOTES_MERGE_WORKTREE. Within this
directory, conflicting notes entries are stored (with conflict markers
produced by ll_merge()) using the SHA1 of the annotated object. The
.git/NOTES_MERGE_WORKTREE directory will only contain the _conflicting_
note entries. The non-conflicting note entries (aka. the partial merge
result) are stored in 'local_tree', and the SHA1 of the resulting commit
is written to 'result_sha1'. The return value from notes_merge() is -1.

The user is told to edit the files within the .git/NOTES_MERGE_WORKTREE
directory in order to resolve the conflicts.

The patch also contains documentation and testcases for the correct setup
of .git/NOTES_MERGE_WORKTREE.

The next part will recombine the partial notes merge result with the
resolved conflicts in .git/NOTES_MERGE_WORKTREE to produce the complete
merge result.

This patch has been improved by the following contributions:
- Jonathan Nieder: Use trace_printf(...) instead of OUTPUT(o, 5, ...)

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This patch has been improved by the following contributions:
- Stephen Boyd: Use "automatically resolves" instead of "auto-resolves"
- Stephen Boyd: Remove unbalanced '('

Thanks-to: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The new -s/--strategy command-line option to 'git notes merge' allow the user
to choose how notes merge conflicts should be resolved. There are four valid
strategies to choose from:

1. "manual" (the default): This will let the user manually resolve conflicts.
   This option currently fails with an error message. It will be implemented
   properly in future patches.

2. "ours": This automatically chooses the local version of a conflict, and
   discards the remote version.

3. "theirs": This automatically chooses the remote version of a conflict, and
   discards the local version.

4. "union": This automatically resolves the conflict by appending the remote
   version to the local version.

The strategies are implemented using the combine_notes_* functions from the
notes.h API.

The patch also includes testcases verifying the correct implementation of
these strategies.

This patch has been improved by the following contributions:
- Jonathan Nieder: Future-proof by always checking add_note() return value
- Stephen Boyd: Use test_commit
- Stephen Boyd: Use correct option name

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Thanks-to: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This continuation of the 'git notes merge' implementation teaches notes-merge
to properly do real merges between notes trees: Two diffs are performed, one
from $base to $remote, and another from $base to $local. The paths in each
diff are normalized to SHA1 object names. The two diffs are then consolidated
into a single list of change pairs to be evaluated. Each change pair consist
of:

  - The annotated object's SHA1
  - The $base SHA1 (i.e. the common ancestor notes for this object)
  - The $local SHA1 (i.e. the current notes for this object)
  - The $remote SHA1 (i.e. the to-be-merged notes for this object)

From the pair ($base -> $local, $base -> $remote), we can determine the merge
result using regular 3-way rules. If conflicts are encountered in this
process, we fail loudly and exit (conflict handling to be added in a future
patch), If we can complete the merge without conflicts, the resulting
notes tree is committed, and the current notes ref updated.

The patch includes added testcases verifying that we can successfully do real
conflict-less merges.

This patch has been improved by the following contributions:
- Jonathan Nieder: Future-proof by always checking add_note() return value
- Stephen Boyd: Use test_commit
- Jonathan Nieder: Use trace_printf(...) instead of OUTPUT(o, 5, ...)
- Junio C Hamano: fixup minor style issues

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Thanks-to: Stephen Boyd <bebarino@gmail.com>
Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Create new function create_notes_commit() which is slightly more general than
commit_notes() (accepts multiple commit parents and does not auto-update the
notes ref). This function will be used by the notes-merge functionality in
future patches.

Also rewrite builtin/notes.c:commit_notes() to reuse this new function.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This initial implementation of 'git notes merge' only handles the trivial
merge cases (i.e. where the merge is either a no-op, or a fast-forward).

The patch includes testcases for these trivial merge cases.

Future patches will extend the functionality of 'git notes merge'.

This patch has been improved by the following contributions:
- Stephen Boyd: Simplify argc logic
- Stephen Boyd: Use test_commit
- Ævar Arnfjörð Bjarmason: Don't use C99 comments.
- Jonathan Nieder: Add constants for common verbosity values
- Jonathan Nieder: Use trace_printf(...) instead of OUTPUT(o, 5, ...)
- Jonathan Nieder: Remove extraneous show() function
- Jonathan Nieder: Clarify handling of empty/missing notes ref in notes_merge()
- Junio C Hamano: fixup minor style issues

Thanks-to: Stephen Boyd <bebarino@gmail.com>
Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

expand_notes_ref() is a new function that performs the DWIM transformation
of "foo" -> "refs/notes/foo" where notes refs are expected.

This is done in preparation for future patches which will also need this
DWIM functionality.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When using combine_notes_concatenate() to concatenate notes, it currently
ensures exactly one newline character between the given notes. However,
when using builtin/notes.c:create_note() to concatenate notes (e.g. by
'git notes append'), it adds a newline character to the trailing newline
of the preceding notes object, thus resulting in _two_ newlines (aka. a
blank line) separating contents of the two notes.

This patch brings combine_notes_concatenate() into consistency with
builtin/notes.c:create_note(), by ensuring exactly _two_ newline characters
between concatenated notes.

The patch also changes a few notes-related selftests accordingly.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The rest of the file uses tabs for indenting. Fix the one function
that doesn't.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The combine_notes_fn functions uses a non-zero return value to indicate
failure. However, this return value was converted to a call to die()
in note_tree_insert().

Instead, propagate this return value out to add_note(), and return it
from there to enable the caller to handle errors appropriately.

Existing add_note() callers are updated to die() upon failure, thus
preserving the current behaviour. The only exceptions are copy_note()
and notes_cache_put() where we are able to propagate the add_note()
return value instead.

This patch has been improved by the following contributions:
- Jonathan Nieder: Future-proof by always checking add_note() return value
- Jonathan Nieder: Improve clarity of final if-condition in note_tree_insert()

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Allow combine_notes functions to request that a note be removed, by setting
the resulting note SHA1 to null_sha1 (0000000...).

For consistency, also teach note_tree_insert() to skip insertion of an empty
note (a note with entry->val_sha1 equal to null_sha1) when there is no note
to combine it with.

In general, an empty note (null_sha1) is treated identically to no note at
all, but when adding an empty note where there already exists a non-empty
note, we allow the combine_notes function to potentially record a new/changed
note. Document this behaviour, and clearly specify how combine_notes functions
are expected to handle null_sha1 in input.

Before this patch, storing null_sha1s in the notes tree were silently allowed,
causing an invalid notes tree (referring to blobs with null_sha1) to be
produced by write_notes_tree().
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This patch introduces no functional change. It consists solely of reordering
functions in notes.c to avoid use-before-declaration errors after applying
the next commit in this series.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

For consistency with other git commands, let the prune subcommand of
git notes accept the long options --dry-run and --verbose for the
respective short ones -n and -v.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These options take an optional argument, but this optional argument was
not documented.

Original patch by Matthieu Moy, but documentation for -B mostly copied
from the explanations of Junio C Hamano.

While we're there, fix a typo in a comment in diffcore.h.
Signed-off-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Users reading git-apply documentation may also be interested in git-am,
especially after receiving an email created with git-format-patch.  The
documentation for git-am already references git-apply.  Add the reverse.
Signed-off-by: NBrad King <brad.king@kitware.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The test would not fail if the filtering failed to do anything, since
in

  test -z "$(git diff HEAD directorymoved:newsubdir)"'

'directorymoved:newsubdir' is not valid, so git-diff fails without
printing anything on stdout.  But then the exit status of git-diff is
lost, whereas test -z "" succeeds.

Use 'git diff --exit-code' instead, which does the right thing and has
the added bonus of showing the differences if there are any.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

check-ref-format --branch requires access to the repository
to resolve refs like @{-1}.

Noticed by Nguyễn Thái Ngọc Duy.

Cc: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The code for each subcommand should be easier to read and manipulate
this way.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* sv/maint-diff-q-clear-fix:
  Fix DIFF_QUEUE_CLEAR refactoring

* rr/svn-fe:
  contrib/svn-fe: Add the svn-fe target to .gitignore
  contrib/svn-fe: Fix IncludePath

* pt/git-gui:
  git-gui: fix size and position of window panes on startup
  git-gui: mc cannot be used before msgcat has been loaded
  git-gui: use textconv filter for diff and blame
  git-gui: Avoid using the <<Copy>> binding as a menu accelerator on win32
  git-gui: fix shortcut creation on cygwin
  git-gui: fix PATH environment for mingw development environment
  git-gui: fix usage of _gitworktree when creating shortcut for windows
  git-gui: fix "Explore Working Copy" for Windows again
  git-gui: fix usage of themed widgets variable
  git-gui: Handle failure of core.worktree to identify the working directory.
  git-gui: check whether systems nice command works or disable it

Add the svn-fe target to .gitignroe.
Signed-off-by: NRamkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Include the path "../../vcs-svn" while compiling it in the Makefile
and change svn-fe.c to include svndump.h.
Signed-off-by: NRamkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* ab/tap:
  test-lib: Remove 3 year old no-op --no-python option
  test-lib: Ignore --quiet under a TAP harness

The --no-python option was added to test-lib.sh by Johannes Schindelin
in early 2006 in abb7c7b3. It was later turned into a no-op by Junio C
Hamano in 7cdbff14 the same year.

Over three years is long enough before removing this old wart which
was retained for backwards compatibility. Our tests have been using
NO_PYTHON and "test_have_prereq PYTHON" for a long time now.
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Running the tests with --quiet under a TAP harness will always fail,
since a TAP harness always needs actual test output to go along with
the plan that's being emitted.

Change the test-lib.sh to ignore the --quiet option under
HARNESS_ACTIVE to work around this. Then users that have --quiet in
their GIT_TEST_OPTS can run tests under prove(1) without everything
breaking.
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* git://repo.or.cz/git-gui:
  git-gui: fix size and position of window panes on startup
  git-gui: mc cannot be used before msgcat has been loaded
  git-gui: use textconv filter for diff and blame
  git-gui: Avoid using the <<Copy>> binding as a menu accelerator on win32
  git-gui: fix shortcut creation on cygwin
  git-gui: fix PATH environment for mingw development environment
  git-gui: fix usage of _gitworktree when creating shortcut for windows
  git-gui: fix "Explore Working Copy" for Windows again
  git-gui: fix usage of themed widgets variable
  git-gui: Handle failure of core.worktree to identify the working directory.
  git-gui: check whether systems nice command works or disable it

When calling rev-parse --parseopt, as in the (now fixed) documented
example

  eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"

the outermost quoting is required, as otherwise all runs of arbitrary
whitespace inside the resulting 'set -- ...' call would be collapsed
into a single space.

This was exposed as a result of our new use of cat <<\EOF since
47e9cd28 (parseopt: wrap rev-parse --parseopt usage for eval
consumption, 2010-06-12), but has always been a problem when handling
arguments containing e.g. newlines.

Point this out in the documentation, and in particular correct the
example that did not have the quotes.
Noticed-by: NJoshua Jensen <jjensen@workspacewhiz.com>
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>