builtin/notes: fix premature failure when trying to add the empty blob

This fixes a small buglet when trying to explicitly add the empty blob
as a note object using the -c or -C option to git notes add/append.
Instead of failing with a nonsensical error message indicating that the
empty blob does not exist, we should rather behave as if an empty notes
message was given (e.g. using -m "" or -F /dev/null).

The next patch contains a test that verifies the fixed behavior.

Found-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t3301: verify that 'git notes' removes empty notes by default

Add test cases documenting the current behavior when trying to
add/append/edit empty notes. This is in preparation for adding
--allow-empty; to allow empty notes to be stored.

Improved-by: Eric Sunshine <sunshine@sunshineco.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/notes: improve naming

In preparation for some needed refactoring, rename struct msg_arg to
struct note_data, and rename its instances from "msg" to "d" (also
removing some unnecessary parentheses). The 'msg_arg' name was
inherited from tag.c, but is not really a good name for the contents
of a note.

Also rename write_note_data() to copy_obj_to_fd(), which more aptly
describes what it actually does: Copying the contents of a git object
(given by its SHA1) into a given file descriptor.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/notes: refactor note file path into struct note_data

Move the 'path' variable from create_note() and into the
note_data struct. Unify cleanup of note_data objects with
a free_note_data() function.

This might not make too much sense on its own, but it makes the
future refactoring of create_note() considerably cleaner.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/notes: simplify early exit code in add()

Remove the need for 'retval' and the unnecessary goto. Also reorganize
to only call free_note_data() is actually needed.

Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/notes: split create_note() to clarify add vs. remove logic

create_note() has a non-trivial interface, and comprises three loosely
related parts:

 1. launching the editor with the note contents, if needed
 2. appending to an existing note, if append_only was given
 3. adding or removing the resulting note, based on whether it's non-empty

Split it along those lines to make the logic clearer: The first part
goes into a new function - prepare_note_data(), with a simpler interface.
The second part is moved into append_edit(), which is the only user of
this code. Finally, the add vs. remove decision is moved into the callers
(add() and append_edit()), keeping the logic for writing the actual note
object in a separate function: write_note_data().

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/notes: add --allow-empty, to allow storing empty notes

Although the "git notes" man page advertises that we support binary-safe
notes addition (using the -C option), we currently do not support adding
the empty note (i.e. using the empty blob to annotate an object). Instead,
an empty note is always treated as an intent to remove the note
altogether.

Introduce the --allow-empty option to the add/append/edit subcommands,
to explicitly allow an empty note to be stored into the notes tree.

Also update the documentation, and add test cases for the new option.

Reported-by: James H. Fisher <jhf@trifork.com>
Improved-by: Kyle J. McKay <mackyle@gmail.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
notes: empty notes should be shown by 'git log'

If the user has gone through the trouble of explicitly adding an empty
note, then "git log" should not silently skip it (as if it didn't exist).

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t3301: modernize style

Make this test script appear somewhat less old-fashioned:

 - Use test helper functions:
    - write_script
    - test_commit
    - test_write_lines
    - test_line_count
    - test_config
    - test_unconfig
    - test_path_is_missing

 - Remove whitespace between redirection operators and their targets.

 - Move preparation of "expect" files into tests.

 - Rename "output" files to "actual".

 - More consistent quoting, especially around commands that might
   expand to nothing.

 - More visibility of important whitespace with ${indent}.

 - Combine pairs of tests that unnecessarily split setup and verification.

Improved-by: Eric Sunshine <sunshine@sunshineco.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Improved-by: Michael Blume <blume.mike@gmail.com>
Improved-by: Jeff King <peff@peff.net>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Windows: correct detection of EISDIR in mingw_open()

According to the Linux open(2) man page, open() must return EISDIR
if a directory was attempted to be opened for writing. Our emulation
in mingw_open() does not get this right: it checks only for O_CREAT.

Fix it to check for a write request.

This fixes a failure in reflog handling, which opens files with
O_APPEND|O_WRONLY, but without O_CREAT, and expects EISDIR when the
named file happens to be a directory.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
use labs() for variables of type long instead of abs()

Using abs() on long values can cause truncation, so use labs() instead.
Reported by Clang 3.5 (-Wabsolute-value, enabled by -Wall).

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
use labs() for variables of type long instead of abs()

Using abs() on long values can cause truncation, so use labs() instead.
Reported by Clang 3.5 (-Wabsolute-value, enabled by -Wall).

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
l10n: Update Catalan translation

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
create_default_files(): don't set u+x bit on $GIT_DIR/config

Since time immemorial, the test of whether to set "core.filemode"
has been done by trying to toggle the u+x bit on $GIT_DIR/config,
which we know always exists, and then testing whether the change
"took".  I find it somewhat odd to use the config file for this
test, but whatever.

The test code didn't set the u+x bit back to its original state
itself, instead relying on the subsequent call to git_config_set()
to re-write the config file with correct permissions.

But ever since

    daa22c6f8d config: preserve config file permissions on edits (2014-05-06)

git_config_set() copies the permissions from the old config file to
the new one.  This is a good change in and of itself, but it
invalidates the create_default_files()'s assumption, causing "git
init" to leave the executable bit set on $GIT_DIR/config.

Reset the permissions on $GIT_DIR/config when we are done with the
test in create_default_files().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'da/difftool'

Fix-up to a new feature in 'master'.

* da/difftool:
  difftool: honor --trust-exit-code for builtin tools
Merge branch 'ta/tutorial-modernize'

* ta/tutorial-modernize:
  gittutorial.txt: remove reference to ancient Git version
Merge branch 'jc/doc-commit-only'

* jc/doc-commit-only:
  Documentation/git-commit: clarify that --only/--include records the working tree contents
Merge git://github.com/git-l10n/git-po

* 'master' of git://github.com/git-l10n/git-po:
  l10n: Update Catalan translation
Merge branch 'jh/empty-notes' into next

A request to store an empty note via "git notes" meant to remove
note from the object but with --allow-empty we will store a (surprise!)
note that is empty.  In the longer run, we might want to deprecate
the somewhat unintuitive "emptying means deletion" behaviour.

* jh/empty-notes:
  t3301: modernize style
  notes: empty notes should be shown by 'git log'
  builtin/notes: add --allow-empty, to allow storing empty notes
  builtin/notes: split create_note() to clarify add vs. remove logic
  builtin/notes: simplify early exit code in add()
  builtin/notes: refactor note file path into struct note_data
  builtin/notes: improve naming
  t3301: verify that 'git notes' removes empty notes by default
  builtin/notes: fix premature failure when trying to add the empty blob
Merge branch 'rs/maint-config-use-labs' into next

* rs/maint-config-use-labs:
  use labs() for variables of type long instead of abs()