t3030-merge-recursive: test known breakage with empty work tree

Sometimes when working with a large repository it can be useful to try
out a merge and only check out conflicting files to disk (for example as
a speed optimization on a server).  Until v1.7.7-rc1~28^2~20
(merge-recursive: When we detect we can skip an update, actually skip
it, 2011-08-11), it was possible to do so with the following idiom:

	# Prepare a temporary index and empty work tree.
	GIT_INDEX_FILE="$PWD/tmp-$$-index" &&
	export GIT_INDEX_FILE &&
	GIT_WORK_TREE="$PWD/tmp-$$-work" &&
	export GIT_WORK_TREE &&
	mkdir "$GIT_WORK_TREE" &&

	# Convince the index that our side is on disk.
	git read-tree -i -m $ours &&
	git update-index --ignore-missing --refresh &&

	# Merge their side into our side.
	bases=$(git merge-base --all $ours $theirs) &&
	git merge-recursive $bases -- $ours $theirs &&
	tree=$(git write-tree)

Nowadays, that still works and the exit status is the same, but
merge-recursive produces a diagnostic if "our" side renamed a file:

	error: addinfo_cache failed for path 'dst'

Add a test to document this regression.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
read-cache.c: refactor --ignore-missing implementation

Move lstat ENOENT handling from refresh_index to refresh_cache_ent and
activate it with a new CE_MATCH_IGNORE_MISSING option.  This will allow
other call paths into refresh_cache_ent to use the feature.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
read-cache.c: extend make_cache_entry refresh flag with options

Convert the make_cache_entry boolean 'refresh' argument to a more
general 'refresh_options' argument.  Pass the value through to the
underlying refresh_cache_ent call.  Add option CE_MATCH_REFRESH to
enable stat refresh.  Update call sites to use the new signature.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-recursive.c: tolerate missing files while refreshing index

Teach add_cacheinfo to tell make_cache_entry to skip refreshing stat
information when a file is missing from the work tree.  We do not want
the index to be stat-dirty after the merge but also do not want to fail
when a file happens to be missing.

This fixes the 'merge-recursive w/ empty work tree - ours has rename'
case in t3030-merge-recursive.

Suggested-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/blame.c: eliminate same_suspect()

Since the origin pointers are "interned" and reference-counted, comparing
the pointers rather than the content is enough.  The only uninterned
origins are cached values kept in commit->util, but same_suspect is not
called on them.

Signed-off-by: David Kastrup <dak@gnu.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin/blame.c::prepare_lines: fix allocation size of sb->lineno

If we are calling xrealloc on every single line, the least we can do
is get the right allocation size.

Signed-off-by: David Kastrup <dak@gnu.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
blame.c: prepare_lines should not call xrealloc for every line

Making a single preparation run for counting the lines will avoid memory
fragmentation.  Also, fix the allocated memory size which was wrong
when sizeof(int *) != sizeof(int), and would have been too small
for sizeof(int *) < sizeof(int), admittedly unlikely.

Signed-off-by: David Kastrup <dak@gnu.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
.gitignore: test-hashmap is a generated file

Prevent the "test-hashmap" program from being accidentally tracked
with "git add" or cluttering "git status" output.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-hashmap.c: drop unnecessary #includes

Per Documentation/CodingGuidelines most C files in git start with
a #include of git-compat-util.h or another header file that includes
it, such as cache.h or builtin.h.  This file doesn't need anything
beyond "git-compat-util.h", so use that.

Remove a #include of the system header <stdio.h> since it is already
included by "git-compat-util.h".

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule: make 'checkout' update_module mode more explicit

This avoids the current awkwardness of having either '' or 'checkout'
for checkout-mode updates, which makes testing for checkout-mode
updates (or non-checkout-mode updates) easier.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule: document module_clone arguments in comments

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule: explicit local branch creation in module_clone

The previous code only checked out branches in cmd_add.  This commit
moves the branch-checkout logic into module_clone, where it can be
shared by cmd_add and cmd_update.  I also update the initial checkout
command to use 'reset' to preserve branches setup during module_clone.

With this change, folks cloning submodules for the first time via:

  $ git submodule update ...

will get a local branch instead of a detached HEAD, unless they are
using the default checkout-mode updates.  This is a change from the
previous situation where cmd_update always used checkout-mode logic
(regardless of the requested update mode) for updates that triggered
an initial clone, which always resulted in a detached HEAD.

This commit does not change the logic for updates after the initial
clone, which will continue to create detached HEADs for checkout-mode
updates, and integrate remote work with the local HEAD (detached or
not) in other modes.

The motivation for the change is that developers doing local work
inside the submodule are likely to select a non-checkout-mode for
updates so their local work is integrated with upstream work.
Developers who are not doing local submodule work stick with
checkout-mode updates so any apparently local work is blown away
during updates.  For example, if upstream rolls back the remote branch
or gitlinked commit to an earlier version, the checkout-mode developer
wants their old submodule checkout to be rolled back as well, instead
of getting a no-op merge/rebase with the rolled-back reference.

By using the update mode to distinguish submodule developers from
black-box submodule consumers, we can setup local branches for the
developers who will want local branches, and stick with detached HEADs
for the developers that don't care.

Testing
=======

In t7406, just-cloned checkouts now update to the gitlinked hash with
'reset', to preserve the local branch for situations where we're not
on a detached HEAD.

I also added explicit tests to t7406 for HEAD attachement after
cloning updates, showing that it depends on their update mode:

* Checkout-mode updates get detached HEADs
* Everyone else gets a local branch, matching the configured
  submodule.<name>.branch and defaulting to master.

The 'initial-setup' tag makes it easy to reset the superproject to a
known state, as several earlier tests commit to submodules and commit
the changed gitlinks to the superproject, but don't push the new
submodule commits to the upstream subprojects.  This makes it
impossible to checkout the current super master, because it references
submodule commits that don't exist in the upstream subprojects.  For a
specific example, see the tests that currently generate the
'two_new_submodule_commits' commits.

Documentation
=============

I updated the docs to describe the 'submodule update' modes in detail.
The old documentation did not distinguish between cloning and
non-cloning updates and lacked clarity on which operations would lead
to detached HEADs, and which would not.  The new documentation
addresses these issues while updating the docs to reflect the changes
introduced by this commit's explicit local branch creation in
module_clone.

I also add '--checkout' to the usage summary and group the update-mode
options into a single set.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: describe 'submodule update --remote' use case

Make it clear that there is no implicit floating going on; --remote
lets you explicitly integrate the upstream branch in your current
HEAD (just like running 'git pull' in the submodule).  The only
distinction with the current 'git pull' is the config location and
setting used for the upstream branch, which is hopefully clear now.

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: convert some match_pathspec_depth() to ce_path_match()

This helps reduce the number of match_pathspec_depth() call sites and
show how match_pathspec_depth() is used.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: convert some match_pathspec_depth() to dir_path_match()

This helps reduce the number of match_pathspec_depth() call sites and
show how m_p_d() is used. And it usage is:

 - match against an index entry (ce_path_match or match_pathspec_depth
   in ls-files)

 - match against a dir_entry from read_directory (dir_path_match and
   match_pathspec_depth in clean.c, which will be converted later)

 - resolve-undo (rerere.c and ls-files.c)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: rename match_pathspec_depth() to match_pathspec()

A long time ago, for some reason I was not happy with
match_pathspec(). I created a better version, match_pathspec_depth()
that was suppose to replace match_pathspec()
eventually. match_pathspec() has finally been gone since 6 months
ago. Use the shorter name for match_pathspec_depth().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
dir.c: prepare match_pathspec_item for taking more flags

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
match_pathspec: match pathspec "foo/" against directory "foo"

Currently we do support matching pathspec "foo/" against directory
"foo". That is because match_pathspec() has no way to tell "foo" is a
directory and matching "foo/" against _file_ "foo" is wrong.

The callers can now tell match_pathspec if "foo" is a directory, we
could make an exception for this case. Code is not executed though
because no callers pass the flag yet.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
pathspec: pass directory indicator to match_pathspec_item()

This patch activates the DO_MATCH_DIRECTORY code in m_p_i(), which
makes "git diff HEAD submodule/" and "git diff HEAD submodule" produce
the same output. Previously only the version without trailing slash
returns the difference (if any).

That's the effect of new ce_path_match(). dir_path_match() is not
executed by the new tests. And it should not introduce regressions.

Previously if path "dir/" is passed in with pathspec "dir/", they
obviously match. With new dir_path_match(), the path becomes
_directory_ "dir" vs pathspec "dir/", which is not executed by the old
code path in m_p_i(). The new code path is executed and produces the
same result.

The other case is pathspec "dir" and path "dir/" is now turned to
"dir" (with DO_MATCH_DIRECTORY). Still the same result before or after
the patch.

So why change? Because of the next patch about clean.c.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
clean: replace match_pathspec() with dir_path_match()

This instance was left out when many match_pathspec() call sites that
take input from dir_entry were converted to dir_path_match() because
it passed a path with the trailing slash stripped out to match_pathspec()
while the others did not. Stripping for all call sites back then would
be a regression because match_pathspec() did not know how to match
pathspec foo/ against _directory_ foo (the stripped version of path
"foo/").

match_pathspec() knows how to do it now. And dir_path_match() strips
the trailing slash also. Use the new function, because the stripping
code is removed in the next patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>