Recent versions of git can be slow to fetch repositories with a
large number of refs (or when they already have a large
number of refs). For example, GitHub makes pull-requests
available as refs, which can lead to a large number of
available refs. This slowness goes away when submodule
recursion is turned off:

  $ git ls-remote git://github.com/rails/rails.git | wc -l
  3034

  [this takes ~10 seconds of CPU time to complete]
  git fetch --recurse-submodules=no \
    git://github.com/rails/rails.git "refs/*:refs/*"

  [this still isn't done after 10 _minutes_ of pegging the CPU]
  git fetch \
    git://github.com/rails/rails.git "refs/*:refs/*"

You can produce a quicker and simpler test case like this:

  doit() {
    head=`git rev-parse HEAD`
    for i in `seq 1 $1`; do
      echo $head refs/heads/ref$i
    done >.git/packed-refs
    echo "==> $1"
    rm -rf dest
    git init -q --bare dest &&
      (cd dest && time git.compile fetch -q .. refs/*:refs/*)
  }

  rm -rf repo
  git init -q repo && cd repo &&
  >file && git add file && git commit -q -m one

  doit 100
  doit 200
  doit 400
  doit 800
  doit 1600
  doit 3200

Which yields timings like:

  # refs  seconds of CPU
     100            0.06
     200            0.24
     400            0.95
     800            3.39
    1600           13.66
    3200           54.09

Notice that although the number of refs doubles in each
trial, the CPU time spent quadruples.

The problem is that the submodule recursion code works
something like:

  - for each ref we fetch
    - for each commit in git rev-list $new_sha1 --not --all
      - add modified submodules to list
  - fetch any newly referenced submodules

But that means if we fetch N refs, we start N revision
walks. Worse, because we use "--all", the number of refs we
must process that constitute "--all" keeps growing, too. And
you end up doing O(N^2) ref resolutions.

Instead, this patch structures the code like this:

  - for each sha1 we already have
    - add $old_sha1 to list $old
  - for each ref we fetch
    - add $new_sha1 to list $new
  - for each commit in git rev-list $new --not $old
    - add modified submodules to list
  - fetch any newly referenced submodules

This yields timings like:

  # refs  seconds of CPU
  100               0.00
  200               0.04
  400               0.04
  800               0.10
  1600              0.21
  3200              0.39

Note that the amount of effort doubles as the number of refs
doubles. Similarly, the fetch of rails.git takes about as
much time as it does with --recurse-submodules=no.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commands like "git status", "git diff" and "git fetch" would fail when the
.gitmodules file contained merge conflicts because the config parser would
call die() when hitting the conflict markers:

    "fatal: bad config file line <n> in <path>/.gitmodules"

While this behavior was on the safe side, it is really unhelpful to the
user to have commands like status and diff fail, as these are needed to
find out what's going on. And the error message is only mildly helpful,
as it points to the right file but doesn't mention that it is unmerged.
Users of git gui were not shown any conflicts at all when this happened.

Improve the situation by checking if the index records .gitmodules as
unmerged. When that is the case we can't make any assumptions about the
configuration to be found there after the merge conflict is resolved by
the user, so assume that all recursion is disabled unless .git/config or
the global config say otherwise.

As soon as the merge conflict is resolved and the .gitmodules file has
been staged subsequent commands again honor any configuration done there.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fix warnings from 'make check'.

 - These files don't include 'builtin.h' causing sparse to complain that
   cmd_* isn't declared:

   builtin/clone.c:364, builtin/fetch-pack.c:797,
   builtin/fmt-merge-msg.c:34, builtin/hash-object.c:78,
   builtin/merge-index.c:69, builtin/merge-recursive.c:22
   builtin/merge-tree.c:341, builtin/mktag.c:156, builtin/notes.c:426
   builtin/notes.c:822, builtin/pack-redundant.c:596,
   builtin/pack-refs.c:10, builtin/patch-id.c:60, builtin/patch-id.c:149,
   builtin/remote.c:1512, builtin/remote-ext.c:240,
   builtin/remote-fd.c:53, builtin/reset.c:236, builtin/send-pack.c:384,
   builtin/unpack-file.c:25, builtin/var.c:75

 - These files have symbols which should be marked static since they're
   only file scope:

   submodule.c:12, diff.c:631, replace_object.c:92, submodule.c:13,
   submodule.c:14, trace.c:78, transport.c:195, transport-helper.c:79,
   unpack-trees.c:19, url.c:3, url.c:18, url.c:104, url.c:117, url.c:123,
   url.c:129, url.c:136, thread-utils.c:21, thread-utils.c:48

 - These files redeclare symbols to be different types:

   builtin/index-pack.c:210, parse-options.c:564, parse-options.c:571,
   usage.c:49, usage.c:58, usage.c:63, usage.c:72

 - These files use a literal integer 0 when they really should use a NULL
   pointer:

   daemon.c:663, fast-import.c:2942, imap-send.c:1072, notes-merge.c:362

While we're in the area, clean up some unused #includes in builtin files
(mostly exec_cmd.h).
Signed-off-by: NStephen Boyd <bebarino@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Introduce two functions:

 - prepare_submodule_summary prepares the revision walker
   to list changes in a submodule.  That is, it:

   * finds merge bases between the commits pointed to this
     path from before ("left") and after ("right") the change;
   * checks whether this is a fast-forward or fast-backward;
   * prepares a revision walk to list commits in the symmetric
     difference between the commits at each endpoint.

   It returns nonzero on error.

 - print_submodule_summary runs the revision walk and saves
   the result to a strbuf in --left-right format.

The goal is just readability.  No functional change intended.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Acked-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When looking for submodules where new commits have been recorded in the
superproject ignore those cases where the submodules commits are already
present locally. This can happen e.g. when the submodule has been rewound
to an earlier state. Then there is no need to fetch the submodule again
as the commit recorded in the newly fetched superproject commit has
already been fetched earlier into the submodule.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Now the behavior of fetch and pull can be configured to the recently added
'on-demand' mode separately for each submodule too.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

To enable the user to change the default behavior of "git fetch" and "git
pull" regarding submodule recursion add the new "on-demand" value which
has just been added to the "--recurse-submodules" command line option.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Until now the --recurse-submodules option could only be used to either
fetch all populated submodules recursively or to disable recursion
completely. As fetch and pull now by default just fetch those submodules
for which new commits have been fetched in the superproject, a command
line option to enforce that behavior is needed to be able to override
configuration settings.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

To be able to access all commits of populated submodules referenced by the
superproject it is sufficient to only then let "git fetch" recurse into a
submodule when the new commits fetched in the superproject record new
commits for it. Having these commits present is extremely useful when
using the "--submodule" option to "git diff" (which is what "git gui" and
"gitk" do since 1.6.6), as all submodule commits needed for creating a
descriptive output can be accessed. Also merging submodule commits (added
in 1.7.3) depends on the submodule commits in question being present to
work. Last but not least this enables disconnected operation when using
submodules, as all commits necessary for a successful "git submodule
update -N" will have been fetched automatically. So we choose this mode as
the default for fetch and pull.

Before a new or changed ref from upstream is updated in update_local_ref()
"git rev-list <new-sha1> --not --branches --remotes" is used to determine
all newly fetched commits. These are then walked and diffed against their
parent(s) to see if a submodule has been changed. If that is the case, its
path is stored to be fetched after the superproject fetch is completed.

Using the "--recurse-submodules" or the "--no-recurse-submodules" option
disables the examination of the fetched refs because the result will be
ignored anyway.

There is currently no infrastructure for storing deleted and new
submodules in the .git directory of the superproject. That's why fetch and
pull for now only fetch submodules that are already checked out and are
not renamed.

In t7403 the "--no-recurse-submodules" argument had to be added to "git
pull" to avoid failure because of the moved upstream submodule repo.

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Thanks-to: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

... while fixing a miscounting.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The new boolean "fetchRecurseSubmodules" config option controls the
behavior for "git fetch" and "git pull". It specifies if these commands
should recurse into submodules and fetch new commits there too and can be
set separately for each submodule.

In the .gitmodules file "submodule.<name>.fetchRecurseSubmodules" entries
are read before looking for them in .git/config. Thus settings found in
.git/config will override those from .gitmodules, thereby allowing the
user to ignore settings given by the remote side while also letting
upstream set reasonable defaults for those users who don't have special
needs.

This configuration can be overridden by the command line option
"--[no-]recurse-submodules" of "git fetch" and "git pull".
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This new boolean option can be used to override the default for "git
fetch" and "git pull", which is to not recurse into populated submodules
and fetch all new commits there too.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Until now you had to call "git submodule update" (without -N|--no-fetch
option) or something like "git submodule foreach git fetch" to fetch
new commits in populated submodules from their remote.

This could lead to "(commits not present)" messages in the output of
"git diff --submodule" (which is used by "git gui" and "gitk") after
fetching or pulling new commits in the superproject and is an obstacle for
implementing recursive checkout of submodules. Also "git submodule
update" cannot fetch changes when disconnected, so it was very easy to
forget to fetch the submodule changes before disconnecting only to
discover later that they are needed.

This patch adds the "--recurse-submodules" option to recursively fetch
each populated submodule from the url configured in the .git/config of the
submodule at the end of each "git fetch" or during "git pull" in the
superproject. The submodule paths are taken from the index.

The hidden option "--submodule-prefix" is added to "git fetch" to be able
to print out the full paths of nested submodules.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When you have a lot of submodules checked out, the time penalty to check
for dirty submodules can easily imply a multiplication of the total time
by the factor 20. This makes the difference between almost instantaneous
(< 2 seconds) and unbearably slow (> 50 seconds) here, since the disk
caches are constantly overloaded.

To this end, the submodule.*.ignore config option was introduced, but it
is per-submodule.

This commit introduces a global config setting to set a default
(porcelain) value for the --ignore-submodules option, keeping the
default at 'none'. It can be overridden by the submodule.*.ignore
setting and by the --ignore-submodules option.

Incidentally, this commit fixes an issue with the overriding logic:
multiple --ignore-submodules options would not clear the previously
set flags.

While at it, fix a typo in the documentation for submodule.*.ignore.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The .gitmodules file is parsed for "submodule.<name>.ignore" entries
before looking for them in .git/config. Thus settings found in .git/config
will override those from .gitmodules, thereby allowing the local developer
to ignore settings given by the remote side while also letting upstream
set defaults for those users who don't have special needs.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The new "ignore" config option controls the default behavior for "git
status" and the diff family. It specifies under what circumstances they
consider submodules as modified and can be set separately for each
submodule.

The command line option "--ignore-submodules=" has been extended to accept
the new parameter "none" for both status and diff.

Users that chose submodules to get rid of long work tree scanning times
might want to set the "dirty" option for those submodules. This brings
back the pre 1.7.0 behavior, where submodule work trees were never
scanned for modifications. By using "--ignore-submodules=none" on the
command line the status and diff commands can be told to do a full scan.

This option can be set to the following values (which have the same name
and meaning as for the "--ignore-submodules" option of status and diff):

"all": All changes to the submodule will be ignored.

"dirty": Only differences of the commit recorded in the superproject and
	the submodules HEAD will be considered modifications, all changes
	to the work tree of the submodule will be ignored. When using this
	value, the submodule will not be scanned for work tree changes at
	all, leading to a performance benefit on large submodules.

"untracked": Only untracked files in the submodules work tree are ignored,
	a changed HEAD and/or modified files in the submodule will mark it
	as modified.

"none" (which is the default): Either untracked or modified files in a
	submodules work tree or a difference between the subdmodules HEAD
	and the commit recorded in the superproject will make it show up
	as changed. This value is added as a new parameter for the
	"--ignore-submodules" option of the diff family and "git status"
	so the user can override the settings in the configuration.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This implements a simple merge strategy for submodule hashes. We check
whether one side of the merge candidates is already contained in the
other and then merge automatically.

If both sides contain changes we search for a merge in the submodule.
In case a single one exists we check that out and suggest it as the
merge resolution. A list of candidates is returned when we find multiple
merges that contain both sides of the changes.

This is useful for a workflow in which the developers can publish topic
branches in submodules and a separate maintainer merges them. In case
the developers always wait until their branch gets merged before tracking
them in the superproject all merges of branches that contain submodule
changes will be resolved automatically. If developers choose to track
their feature branch the maintainer might get a conflict but git will
search the submodule for a merge and suggest it/them as a resolution.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In some use cases it is not desirable that "git status" considers
submodules that only contain untracked content as dirty. This may happen
e.g. when the submodule is not under the developers control and not all
build generated files have been added to .gitignore by the upstream
developers. Using the "untracked" parameter for the "--ignore-submodules"
option disables checking for untracked content and lets git diff report
them as changed only when they have new commits or modified content.

Sometimes it is not wanted to have submodules show up as changed when they
just contain changes to their work tree (this was the behavior before
1.7.0). An example for that are scripts which just want to check for
submodule commits while ignoring any changes to the work tree. Also users
having large submodules known not to change might want to use this option,
as the - sometimes substantial - time it takes to scan the submodule work
tree(s) is saved when using the "dirty" parameter.

And if you want to ignore any changes to submodules, you can now do that
by using this option without parameters or with "all" (when the config
option status.submodulesummary is set, using "all" will also suppress the
output of the submodule summary).

A new function handle_ignore_submodules_arg() is introduced to parse this
option new to "git status" in a single location, as "git diff" already
knew it.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The simple test for an existing .git directory gives an incorrect result
if .git is a file that records "gitdir: overthere". So for submodules that
use a .git file, "git status" and the diff family - when the "--submodule"
option is given - did assume the submodule was not populated at all when
a .git file was used, thus generating wrong output or no output at all.

This is fixed by using read_gitfile_gently() to get the correct location
of the .git directory. While at it, is_submodule_modified() was cleaned up
to use the "dir" member of "struct child_process" instead of setting the
GIT_WORK_TREE and GIT_DIR environment variables.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since 1.7.0 submodules are considered dirty when they contain untracked
files. But when git status is called with the "-uno" option, the user
asked to ignore untracked files, so they must be ignored in submodules
too. To achieve this, the new flag DIFF_OPT_IGNORE_UNTRACKED_IN_SUBMODULES
is introduced.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When encountering a dirty submodule while doing "git diff --submodule"
print an extra line for new untracked content and another for modified
but already tracked content. And if the HEAD of the submodule is equal
to the ref diffed against in the superproject, drop the output which
would just show the same SHA1s and no commit message headlines.

To achieve that, the dirty_submodule bitfield is expanded to two bits.
The output of "git status" inside the submodule is parsed to set the
according bits.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Rather than only clearing GIT_INDEX_FILE, take the list of environment
variables to clear from local_repo_env, appending the settings for
GIT_DIR and GIT_WORK_TREE.
Signed-off-by: NGiuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The strbuf used in add_submodule_odb() was never released. So for every
submodule - populated or not - we leaked its object directory name when
using "git diff*" with the --submodule option.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Even when the environment was given for the top-level process, checking
in the submodule work tree should use the index file associated with the
work tree of the submodule.  Do not export it to the environment.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since commit 8e08b4 git diff does append "-dirty" to the work tree side
if the working directory of a submodule contains new or modified files.
Lets do the same when the --submodule option is used.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Until now a submodule only then showed up as modified in the supermodule
when the last commit in the submodule differed from the one in the index
or the diffed against commit of the superproject. A dirty work tree
containing new untracked or modified files in a submodule was
undetectable when looking at it from the superproject.

Now git status and git diff (against the work tree) in the superproject
will also display submodules as modified when they contain untracked or
modified files, even if the compared ref matches the HEAD of the
submodule.
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NNanako Shiraishi <nanako3@lavabit.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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

i686-apple-darwin9-gcc-4.0.1 (GCC) 4.0.1 (Apple Inc. build 5493) compiler
(and probably others) mistakenly thinks variable 'right' is used
before assigned.  Work around it by giving it a fake initialization.
Signed-off-by: NDavid Aguilar <davvid@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When you use the option --submodule=log you can see the submodule
summaries inlined in the diff, instead of not-quite-helpful SHA-1 pairs.

The format imitates what "git submodule summary" shows.

To do that, <path>/.git/objects/ is added to the alternate object
databases (if that directory exists).

This option was requested by Jens Lehmann at the GitTogether in Berlin.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>